How to mix two liquid substances? For example, some acid and water? It would seem that this task is from the series “twice two - four”. What could be easier: pour two liquids together, in some suitable container, and that's it! Or pour one liquid into a container where another is already located. Alas, this is the same simplicity, which, according to the apt popular expression, is worse than theft. Because things can end very sadly!
Instruction
There are two containers, one contains concentrated sulfuric acid, the other contains water. How to mix them correctly? Pour acid into water or, conversely, water into acid? The price of a wrong decision in theory can be a low score, but in practice - in best case, severe burn.
Why? And because concentrated sulfuric acid, firstly, is much denser than water, and secondly, it is extremely hygroscopic. In other words, it actively absorbs water. Thirdly, this absorption is accompanied by the release of a large amount of heat.
If water is poured into a container of concentrated sulfuric acid, the first portions of water will “spread” over the surface of the acid (since water is much less dense), and the acid will begin to greedily absorb it, releasing heat. And this heat will be so much that the water will literally “boil” and the spray will fly in all directions. Naturally, not passing the unlucky experimenter. It’s not very pleasant to get burned with “clean” boiling water, but if you consider that there will probably be more acid in the water splashes. The prospect is becoming quite gloomy!
That is why many generations of chemistry teachers forced their students to literally memorize the rule: “First water, then acid! Otherwise, a big disaster will happen! Concentrated sulfuric acid should be added to water, in small portions, with stirring. Then the above unpleasant situation will not happen.
A reasonable question: with sulfuric acid, it’s clear, but what about other acids? What is the right way to mix them with water? In what order? You need to know the density of the acid. If it is denser than water, for example, concentrated nitrogen, it should be poured into water in the same way as sulfuric, observing the above conditions (little by little, with stirring). Well, if the density of the acid differs very slightly from the density of water, as in the case of acetic acid, then it doesn't matter.
Attention, only TODAY!
All interesting
increased attention and caution, as well as compliance with special safety measures, is a necessary condition when working with acids. Persons who have reached the age of 18 are allowed to work with acids, while a prerequisite is the completion of a course ...
Sulfurous acid is an inorganic acid of medium strength. Due to instability, it is impossible to prepare its aqueous solution with a concentration of more than 6%, otherwise it will begin to decompose into sulfuric anhydride and water. Chemical properties sulfurous acidSulfurous…
Sulfuric acid is an odorless, colorless oily liquid. Refers to strong acids and dissolves in water in any ratio. It has a huge application in industry. Sulfuric acid is a fairly heavy liquid, its density is…
Sulfuric acid physical properties- heavy oily liquid. It is odorless and colorless, hygroscopic, soluble in water. A solution with an H2SO4 content of less than 70% is usually called dilute sulfuric acid, more than 70% - ...
Hydrochloric (hydrochloric, HCl) acid is a colorless, very caustic and poisonous liquid, a solution of hydrogen chloride in water. At a strong concentration (38% of the total mass at a temperature of 20 ° C environment) - “smoke”, fog and vapors ...
Sulfuric acid has the chemical formula H2SO4. It is a heavy oily liquid, colorless or with a yellowish tint, which is given to it by impurities of metal ions, such as iron. Sulfuric acid is very hygroscopic, absorbing water vapor easily.…
Sulfuric acid is one of the five strongest acids. The need to neutralize this acid arises, in particular, in the event of its leakage and if there is a threat of poisoning to it. Instruction 1 A sulfuric acid molecule consists of two atoms ...
Since ancient times, when explaining how to mix concentrated sulfuric acid with water, teachers made students memorize the rule: “First water, then acid!” The fact is that if you do the opposite, the first portions are lighter ...
Sulfuric acid, which has the chemical formula H2SO4, is a heavy, dense liquid with an oily consistency. It is very hygroscopic, easily mixed with water, and it is imperative to pour acid into water, in no case vice versa.…
In any car there is a source of current, this source is the battery. Since the battery is a reusable element, it can be recharged and the electrolyte in it can be changed. Previously, both acidic and ...
Ferrous sulfates are inorganic chemical substances, they are divided into varieties. There is ferrous sulfate (2) and ferric sulfate (3). There are many ways to obtain these sulfate salts. You will need Iron,…
What happens when an acid is combined with a salt? The answer to this question depends on which acid it is and which salt it is. A chemical reaction (that is, the transformation of substances, accompanied by a change in their composition) between an acid and a salt can ...
For safety and ease of use, it is recommended to buy the most dilute acid, but sometimes it has to be diluted even more at home. Be sure to wear body and face protection as concentrated acids cause severe chemical burns. To calculate the required amount of acid and water, you will need to know the molarity (M) of the acid and the molarity of the solution you need to get.
Steps
How to calculate the formula
- The formula will also use the value V 1. This is the volume of acid we will be adding to the water. We probably won't need the whole bottle of acid, though we don't know the exact amount yet.
-
Decide what the result should be. The required concentration and volume of acid is usually indicated in the text of the chemistry problem. For example, we need to dilute the acid to a value of 2M, and we need 0.5 liters of water. Let us denote the required concentration as C2, and the required volume - as V 2.
- If you are given other units, first convert them to molarity units (moles per liter) and liters.
- If you don't know what concentration or volume of acid you need, ask a teacher or someone well versed in chemistry.
-
Write a formula to calculate the concentration. Each time you dilute an acid, you will use the following formula: C 1 V 1 = C 2 V 2. This means that the original concentration of a solution times its volume equals the concentration of the diluted solution times its volume. We know this to be true because the concentration times the volume equals the total acid, and the total acid will remain the same.
- Using the data from the example, we write this formula as (6M)(V 1)=(2M)(0.5L).
-
Solve equation V 1. The value of V 1 will tell us how much concentrated acid we need to get the desired concentration and volume. Let's rewrite the formula as V 1 \u003d (C 2 V 2) / (C 1), then substitute the known numbers.
- In our example, we get V 1 =((2M)(0.5L))/(6M). This equals approximately 167 milliliters.
-
Calculate the required amount of water. Knowing V 1, that is, the amount of acid available, and V 2, that is, the amount of solution that you get, you can easily calculate how much water you need. V 2 - V 1 = required volume of water.
- In our case, we want to get 0.167 liters of acid per 0.5 liters of water. We need 0.5 liters - 0.167 liters \u003d 0.333 liters, that is, 333 milliliters.
-
Put on safety goggles, gloves and a gown. You will need special glasses that will cover your eyes and sides. Wear gloves and a gown or apron to avoid burning your skin and clothes.
Work in a well ventilated area. If possible, work under the included hood - this will prevent acid vapors from harming you and surrounding objects. If you don't have a hood, open all windows and doors or turn on a fan.
-
Find out where the source of running water is. If acid gets in your eyes or on your skin, you will need to rinse the affected area under cool, running water for 15 to 20 minutes. Do not start work until you find out where the nearest sink is.
- When rinsing your eyes, keep them open. Look up, down, to the sides so that the eyes are washed from all sides.
-
Know what to do if you spill acid. You can buy a special kit for collecting spilled acid, which will include everything you need, or purchase neutralizers and absorbents separately. The process described below is applicable to hydrochloric, sulfuric, nitric and phosphoric acids. Other acids may require different handling.
- Ventilate the room by opening windows and doors and turning on the exhaust hood and fan.
- Apply A little sodium carbonate (baking soda), sodium bicarbonate, or calcium carbonate on the outer edges of the puddle to prevent splashing of acid.
- Gradually fill the entire puddle towards the center until you have completely covered it with the neutralizing agent.
- Mix thoroughly with a plastic stick. Check the pH value of the puddle with litmus paper. Add more neutralizing agent if this value exceeds 6-8, and then wash the area with plenty of water.
Explore what you already have. Look for the acid concentration symbol on the packaging or in the task description. Usually this value is indicated as molarity, or molar concentration (briefly - M). For example, 6M acid contains 6 moles of acid molecules per liter. Let's call this initial concentration C1.
How to dilute acid
-
Cool the water with people. This should only be done if you will be working with high concentrations of acids, such as 18M sulfuric acid or 12M hydrochloric acid. Pour water into a container, place the container on ice for at least 20 minutes.
- Most often, water at room temperature is sufficient.
-
Pour distilled water into a large flask. For tasks that require extreme precision (for example, titrimetric analysis), use a volumetric flask. For all other purposes, a regular conical flask will do. The entire required volume of liquid must fit in the container, and there must also be room so that the liquid does not spill.
- If the capacity of the container is known, there is no need to accurately measure the amount of water.
Currently, the choice of batteries is huge - on sale you can find ready-to-use power sources, as well as dry-charged batteries, which require electrolyte preparation and filling before operation. Further maintenance of batteries is often carried out in services. For various reasons, it may be necessary to prepare the solution yourself. For this event to be successful, you should know how to make an electrolyte at home.
Electrolyte - an electrically conductive solution containing distilled water and sulfuric acid, caustic potassium or sodium, depending on the type of power source.
The concentration of sulfuric acid in the battery
This indicator of acidity directly depends on the required density of the electrolyte. Initially, the average concentration of this solution in a car battery is about 40%, depending on the temperature and climate in which the power source is used. During operation, the acid concentration drops to 10–20%, which affects the performance of the battery.
At the same time, it should be understood that the battery sulfur component is the purest liquid, which consists of 93% directly from acid, the remaining 7% are impurities. On the territory of Russia, the production of this chemical is strictly regulated - the products must comply with the requirements of GOST.
Differences in electrolytes for different types of batteries
Although the principle of the solution is the same for different power sources, you should be aware of some differences in composition. Depending on the composition, it is customary to isolate alkaline and acidic electrolytes.
Alkaline batteries
This type of power supply is characterized by the presence of nickel hydroxide, barium oxide and graphite. The electrolyte in this type of battery is a 20% solution of caustic potassium. Lithium monohydrate is traditionally used to extend battery life.
Alkaline power sources are distinguished by the absence of interaction between the potassium solution and the substances formed during battery operation, which contributes to the maximum reduction in consumption.
acid batteries
This type of food source is one of the most traditional, and therefore the solution in them is familiar to many - a mixture of distilled water and sulfuric solution. The electrolyte concentrate for lead-acid batteries is cheap and is characterized by the ability to conduct a large amount of current. The density of the liquid must correspond to climatic indicators.
Other types of batteries: is it possible to prepare an electrolyte for them yourself?
Separately, I would like to draw attention to modern lead-acid power supplies - gel and AGM. They can also be filled with a solution prepared by oneself, which is in a specific form - in the form of a gel or inside separators. To refuel gel batteries, you will need another chemical component - silica gel, which will thicken the acid solution.
Nickel-cadmium and iron-nickel batteries
Unlike lead sources food, cadmium and iron-nickel are filled with an alkaline solution, which is a mixture of distilled water and caustic potassium or sodium. Lithium hydroxide, which is part of this solution for certain temperature conditions, allows you to increase the service life of the battery.
Table 2. The composition and density of the electrolyte for cadmium- and iron-nickel and batteries.
How to prepare an electrolyte at home: safety precautions
Preparing a solution is working with acids and alkalis, so precautions are necessary for the most experienced people. Before starting the action, prepare protective equipment:
- latex gloves
- clothing and apron resistant to chemicals;
- protective glasses;
- ammonia, soda ash or boron solution to neutralize acid and alkali.
Equipment
To prepare the battery electrolyte, in addition to the power source itself, the following items will be required:
- container and stick resistant to acids and alkalis;
- distilled water;
- instruments for measuring the level, density and temperature of the solution;
- battery sulfuric liquid - for acid batteries, solid or liquid alkalis, lithium - for the corresponding types of batteries, silica gel - for gel batteries.
Process sequence: making an electrolyte for a lead-acid power source
Before starting work, read the information given in table 3. It will allow you to select the required volume of liquids. The batteries are filled from 2.6 to 3.7 liters acid solution. We recommend diluting approximately 4 liters of electrolyte.
Table 3. Proportions of water and sulfuric acid.
- Pour the desired volume of water into a container resistant to caustic substances.
- Water should be diluted with acid gradually.
- At the end of the infusion process, measure the density of the resulting electrolyte using a hydrometer.
- Let the composition stand for about 12 hours.
Table 4. Electrolyte density for different climates.
The concentration of the acid solution must be related to the minimum temperature at which the battery is operated. If the liquid turned out to be too concentrated, it must be diluted with distilled water.
Watch the video on how to measure the density of an electrolyte.
Attention! Do not pour water into acid! As a result of this chemical reaction boiling of the composition may occur, which will lead to its splashing and the possibility of getting acid burns!
Please note that heat is generated during mixing of the components. The cooled solution should be poured into the prepared battery.
How to dilute the electrolyte for an alkaline power source
The density and amount of electrolyte in such batteries is indicated in the operating instructions for the power source or on the manufacturer's website.
- Pour distilled water into a bowl.
- Add lye.
- Mix the solution, seal it tightly and let it brew for 6 hours.
- After the time has elapsed, drain the resulting light solution - the electrolyte is ready.
If a precipitate appears, it should be stirred. If by the end of settling it remains, drain the electrolyte so that the sediment does not get into the battery - this will lead to a decrease in its service life.
Attention! During work, the temperature of the alkaline solution should not exceed 25 degrees Celsius. If the liquid becomes excessively hot, cool it down.
After bringing the solution to room temperature and pouring it into the battery, the power source must be fully charged with a current that is 10% of the battery capacity (60Ah - 6A).
As you can see, preparing an electrolyte solution is not such a difficult task. The main thing is to clearly define necessary quantity ingredients and be mindful of safety. Have you tried diluting the electrolyte yourself? Share your experience with our readers in the comments.
1. Are the following statements about the right to a safe job in the school la-bo-ra-to-rii true?
A. When pro-ve-de-nii of experiments with the end-cen-tri-ro-van-ny-mi dis-tvo-ra-mi sour-lot and sch-lo-whose not-about-ho-di -mo all-gda on-de-vat re-zi-no-vye per-chat-ki.
B. Experiments with let-tu-chi-mi, poison-vi-you-mi-substances-mi are carried out only under draft.
1) only A is true
2) only B is true
3) both statements are true
2. Which of the gases that are in the at-mo-sphere in rezul-ta-te de-i-tel-no-sti man-lo-ve-ka, most- more tok-si-chen?
1) CO2 2) NO23) CH4 4) H2
3. What mixture can be poured-de-pour-fil-tro-wa-ni-eat?
1) sa-ha-ra and water
2) sand and water
3) water and ben-zi-on
4) sand and sa-ha-ra
4. Are the judgments about a safe o-ra-sche-nii with chi-mi-che-ski-mi things true?
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
5. Are the following statements about the right to work in the school la-bo-ra-to-rii true?
A. On any su-de, in some swarm things are stored, there must be these ket-ki with the name-no-i-mi or form -la-mi things.
B. Experiments with go-ryu-chi-mi and ed-ki-mi-studies-mi not-about-ho-di-mo-to be done in glasses - own or la-bo -ra-tor-nyh.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
6. Are the following judgments about the right-vi-lah without-dangerous work in the chi-mi-che-la-bo-ra-to-rii true?
B. Sulfuric acid should be dissolved in hot water.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
7. Are the following judgments about pure substances and mixtures and ways of their separation true?
A. Pure substances have a hundred-yang composition.
B. A mixture of boiled salt with river sand can be de-poured with the help of adding water and then fil-tro-va-nia and you-pa-ri-va-nia.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
8. Are the following statements about the exhaust gases of auto-mo-bi-ley true?
A. The most harmful component of exhaust gases is CO2, since it is a vapor gas.
B. Nitrogen oxides are formed by the interaction of auto-mo-bil-no-go top-li-va with nitrogen air -Ha.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
9. Are the following judgments about the right-vi-lah without-dangerous work in the chi-mi-che-la-bo-ra-to-rii and with pre-pa-ra-ta-mi be-that-howl chemistry?
A. In la-bo-ra-to-rii, are there sour-lo-you in ras-tvo-re define-de-la-yut taste.
B. When working with pre-pa-ra-ta-mi would-howl chemistry, containing alkali, not-about-ho-di-mo use-pol-zo -vat re-zi-no-vye per-chat-ki.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
10. Are the judgments about the ways of times-de-le-tion mixtures true?
A. A mixture of eta-no-la and water can be de-poured with the help of a de-li-tel-ny crow-ki.
B. The action of a magnet on a mixture of iron and aluminium-mi-ni-e-sawdust is a physical way -de-le-tion of substances.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
11. Are the following judgments about dealing with gases in the process of la-bo-ra-tor-ny experiments true?
A. Before setting fire to the water, it’s not-about-ho-di-mo to check for cleanliness.
B. By-lu-cha-e-my from ber-to-le-to-howl salt, chlorine cannot be determined by pa-hu.
1) Only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
12. Are the following judgments about pra-vi-lah without dangerous work in la-bo-ra-to-rii true?
a. glasses.
B. When you re-me-shi-va-nii liquid in the test tube, you can close the hole of the test tube with your hand.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
13. Are the following judgments about the process of filtering and about the use of chi-mi-che-sky re-ak true? -tsy che-lo-ve-com?
A. To speed up the process of filter-tro-va-niya, the beveled end of the v-ron-ki should be pressed against the wall-ke hi-mi-che-sko th hundred-ka-on.
B. In the os-no-ve you-smelting chu-gu-on and steel lie oxide-li-tel-no-re-sta-no-vi-tel-ny reactions.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
14. Sodium chloride can be poured out of its water with the help of
1) filtering
2) you-pa-ri-va-nia
3) mag-ni-ta
4) from-sta-and-va-nia
15. Are the judgments about the ways of times-de-le-ning mixtures true?
A. It is possible to purify sea water from the salts dissolved in it with the help of filtration.
b.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
16. Are the judgments about the right to use and store pre-pa-ra-tov by-it-howling chemistry true?
a. safe for children and animals.
B. Ras-tvo-ri-te-whether and mo-th-means-to-start-ka-et-stor-thread in places accessible to children.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
17. Are the judgments about the safe o-ra-sche-nii with chi-mi-che-ski-mi things true?
A. Once a mercury thermo-meter and mercury flowing out of it should be thrown into the trash can.
B. Kras-ka-mi, so-der-zha-schi-mi lead ions, do not re-ko-men-du-e-xia to cover children's toys-rush-ki and su-doo.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
18. Are the following judgments about right-vi-lah without dangerous work in chi-mi-che-sky la-bo-ra-to-rii true?
A. Methane forms explosive mixtures with air.
B. To dissolve sulfuric acid, it follows by adding water to it.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
19. Are the following statements about pure substances and mixtures correct?
A. Natural gas is a pure substance.
B. Diamond is a mixture of substances.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
20. Are the following statements about water correct?
A. Sea water has a greater density than river water, since it contains a significant but greater neck the composition of dissolved salts.
B. Water ob-la-da-et pa-my-tyu, in this way water can be used for pi-si in-for-ma-tion.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
21. Are the following judgments about the right to store and receive vi-ta-mi-nov true?
A. Vi-ta-min C can be required in an unlimited quantity.
B. Keep the thread and take the mother of the vi-ta-mi-us in those-che-not-limited-no-chen-no-go-pe-ri-o-yes time-me-no.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
22. Are the following statements about coal-acid gas true?
A. The number of coal-le-sour-lo-go gas in the at-mo-sphere is one hundred-yan-but growing blah-go-da-rya de-i-tel-no- sti che-lo-ve-ka.
B. Coal-le-sour gas is the most harmful component of exhaust gases.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
23. What are the p-me-si in drinking-thie-howl water the most-bo-leak-sich-us for a person-lo-ve-ka?
1) sodium and calcium chlorides
2) sul-fa-you calcium and magnesium
3) salts of lead and mercury
4) ras-tvo-ri-my car-bo-on-you
24. Are the following statements about the right to work in the school la-bo-ra-to-rii true?
A. Substances, na-ho-dya-schi-e-sya in la-bo-ra-to-ri, for-pro-s-ta-tasting, even if they in everyday life they are used for food (for example, sodium chloride).
B. When acid is applied to the skin, the affected area must be washed with a large amount of alkali solutions.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
25. Are the following statements about the right to a safe job in a school la-bo-ra-to-rii true?
A. In order to extinguish the flame of alcohol, it should be blown out.
B. When on-gre-va-nii pro-bi-ki with ra-tvo-rum, it should be ras-po-la-gat strictly ver-ti-cal-but.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
26. Are the following statements about the right to work in the school la-bo-ra-to-rii true?
A. All experiments conducted in la-bo-ra-to-rii should be for-pi-sa-na in la-bo-ra-tor-ny magazine.
B. When heating liquid and solid substances in test tubes and flasks, it is impossible to direct them from the holes to yourself and co-se-day .
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
27. Are the following judgments about the rights of the storage of vi-ta-mi-nov and the pre-knowledge of my means correct? ?
A. Storing vi-ta-mi-nov does not require strict compliance with the rules indicated in the instructions.
B. To remove greasy stains from the top-no-sti according to the su-dy, purpose-le-co-ob-raz-but use properties that have an alkaline environment.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
28. Are the judgments about a safe o-ra-sche-nii with chi-mi-che-ski-mi things true?
A. Once a mercury thermo-meter and mercury flowing out of it should be thrown into the trash can.
b. rush-ki and su-du.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
29. Are the following judgments about right-vi-lakh without-dangerous work in chi-mi-che-sky la-bo-ra-to-rii true?
A. In la-bo-ra-to-rii, you can’t know about things.
B. Water can be boiled in any glass-lyan-noy in a su-de.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
30. Are the judgments about a safe o-ra-sche-nii with chi-mi-che-ski-mi things true?
A. Once a mercury thermo-meter and mercury flowing out of it should be thrown into the trash can.
b. rush-ki and su-du.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
31. Are the following statements about ozone true?
A. Ozone in the stra-to-sphere-re-glob-scha-is part of the ultra-tra-fi-o-le-to-go from-lu-che-niya, protecting from this from -lu-che-niya live or-ga-niz-we.
B. Ozone is a completely harmless gas, therefore it is preferable to use it instead of chlorine to purify water.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
32. Are the judgments about eco-lo-gi-che-safety true?
А. nyh roads and auto-mo-bil-ny ma-gi-stra-lei.
B. Vegetable plants grown with the use of mi-non-real fertilizers, not before -become-la-yut danger-no-sti for or-ga-niz-ma che-lo-ve-ka.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
33. Are the judgments about the ways of times-de-le-tion of mixtures true?
a.
B. Raz-de-le-tion of a mixture of water and this-no-la is possible in a way of filtering.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
34. Are the following judgments about the right-vi-lah without-dangerous work-bo-you in the chi-mi-che-la-bo-ra-to-rii and storage of things in everyday life?
A. When pa-da-nii dissolves sour-lo-you on the skin, it should be washed with water and par-ra-bo-tat pi-tie-rum howling soda.
b. ko in ho-lo-dil-ni-ke.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
35. Are the following judgments about the ways of times-de-le-tion mixtures correct?
A. To separate a mixture of river sand and iron filings, you can use a magnet.
B. For the de-le-tion of the sediment from the race-creative-ra, you can use the filter-tro-val-boo-ma-gu.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
36. Are the following statements about water correct?
A. Water-to-wire-water contains an admixture of ra-tvo-ri-my salts - sulfates and hydro-ro-car-bo-na-tov.
B. Water ob-la-da-et pa-my-tyu, in this way, me-ha-ni-che-actions, for example, sound-co-le- ba-niya, change its properties.
1) only A is true
2) only B is true
3) both statements are true
4) both statements are not true
37. Are the following judgments about the right-vi-lah without a dangerous job in the chi-mi-che-la-bo-ra-to-rii true?
A. In a men-sur-ke, you can heat water.
B. Hot sodium can be extinguished with water.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
38. Are the following judgments about the ways of co-bi-ra-niya gases in la-bo-ra-to-rii correct?
A. Coal-le-sour gas can be collected in a vessel in a way that you-press-non-air-spirit-ha.
B. Oxygen can be collected in a vessel both in the way of expelling air, and in the way of displacing water.
1) Only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
39. Are the following judgments about the ways of co-be-ing coal-acid-lo-go gas in la-bo-ra-to-rii correct?
A. Coal-le-sour gas in la-bo-ra-to-rii in-lu-cha-yut raz-lo-same-ni-em car-bo-on-that calcium when heated -va-nii.
B. For la-bo-ra-tor-ny experiments, coal-le-sour gas is in-lu-cha-yut when heating-va-ni kar-bo-na-ta am-mo-niya .
1) Only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
40. Are the judgments about eco-lo-gi-che-sky safety of chi-mi-che-productions true?
a. .
B. From-go-dy re-ra-bot-ki lead ores do not pose a threat to the environment and human health lo-ve-ka.
1) only A is true
2) only B is true
3) both sentences are true
4) both judgments of non-faith
Loading...