Chemistry, 28.11.2019 19:31, snowprincess99447

Asample of hydrogen gas was collected over water at 21°c and at a pressure equal to the atmospheric pressure of 748 mm hg. the volume of the sample was 512 ml. how many grams of h2 are in the sample? the vapor pressure of water at 21°c is 18.7 mmhg.

Answers: 2

Show answers

Answers

answered: katiewhitlock1014

The amount of hydrogen gas in the sample is 0.0408 g

Explanation:

We are given:

Vapor pressure of water = 18.7 mmHg

Total vapor pressure = 748 mmHg

Vapor pressure of hydrogen gas = Total vapor pressure - Vapor pressure of water = (748 - 18.7) mmHg = 729.3 mmHg

To calculate the amount of hydrogen gas collected, we use the equation given by ideal gas which follows:

PV=nRT

where,

P = pressure of the gas = 729.3 mmHg

V = Volume of the gas = 512 mL = 0.512 L ( 1 mL = 0.001 L)

T = Temperature of the gas = $21^oC=[21+273]K=294\ K$

R = Gas constant = $62.3637\text{ L.mmHg }mol^{-1}K^{-1}$

n = number of moles of hydrogen gas = ?

Putting values in above equation, we get:

$729.3mmHg\times 0.512L=n\times 62.3637\text{ L.mmHg }mol^{-1}K^{-1}\times 294K\\\\n=\frac{729.3\times 0.512}{62.3637\times 294}=0.0204mol$

To calculate the mass from given number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of hydrogen gas = 0.0204 moles

Molar mass of hydrogen gas = 2 g/mol

Putting values in above equation, we get:

$0.0204mol=\frac{\text{Mass of hydrogen gas}}{2g/mol}\\\\\text{Mass of hydrogen gas}=(0.0204mol\times 2g/mol)=0.0408g$

Hence, the amount of hydrogen gas in the sample is 0.0408 g

answered: Guest

answer : one can design an experiment using a liquid and an additive that can be added to the liquid and observe the chemical changes in the reaction species.

one would need a beaker which is filled with a known amount of the liquid in which thermometer is placed to measure the temperature changes; after addition of the additive to the liquid solution one can note down the temperature change and find whether the reaction is endothermic or exothermic in nature. by subtracting the initial temperature value with the final temperature one can find the temperature changes.

various combinations of liquid and additive can be used. liquid in this case can be a known quantity of water and additives can be epsom salt or without epsom salt the experiment can be conducted to notice the changes. water and ice, hydrogen peroxide and dry yeast, vinegar and baking soda,etc.

answered: Guest

every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. therefore, there must be the same number of atoms of each element on each side of a chemical equation.

Other questions on the subject: Chemistry

Chemistry, 21.06.2019 20:30, notkeandre9

9. write the chemical equation for the following word equations. include symbols for physical states in the equation. a. solid zinc sulfide + oxygen gas -> solid zinc oxide + sulfur dioxide gas b. aqueous hydrochloric acid + aqueous barium hydroxide -> aqueous barium chloride + water

Answers: 1

continue

Chemistry, 22.06.2019 17:00, princessakosua2

The msds for glacial acetic acid says that it is a flammable liquid that can severely burn any human tissue it comes in contact with. it reacts with bases, various metals, and strong oxidizing agents. its vapors can form explosive mixtures with air.

Answers: 1

continue

Chemistry, 23.06.2019 01:00, akluke6059

Which statement characterizes synthetic polymers? a. they come from animals and plants. b. they are found in nature. c. they are made in a lab. d. they are components of starch.

Answers: 1

continue

Chemistry, 23.06.2019 03:00, rhianna18

In november 1987, a massive iceberg broke loose from the antartic ice mass and floated free in the ocean. the chunk of ice was estimated to be 98 mi long, 25 mi wide, and 750 ft thick. a typical backyard swimming pool contains about 24,000 gallons of water. how many of these pools could you fill from the water in this iceberg? (assume the iceberg is a rectangular solid of the above dimensions and consists of water only). express answer in scientific notation.

Answers: 1

continue

Do you know the correct answer?

Asample of hydrogen gas was collected over water at 21°c and at a pressure equal to the atmospheric...