Chemistry Unit Test Review

A scientist is examining a mixture of nitrogen, hydrogen, and ammonia. The individual pressures that are exerted by nitrogen and hydrogen are 0.26 atm and 0.28 atm, respectively. If the total pressure is 0.90 atm, what is the partial pressure of ammonia?

0.36 atm

A tire at 21°C has a pressure of 0.82 atm. Its temperature decreases to -3.5°C. If there is no volume change in the tire, what is the pressure after the temperature change?

0.75 atm

Consider the reaction. How many grams of carbon should be burned in an excess of oxygen at STP to obtain 2.21 L of carbon dioxide?

1.18 g

The following balanced equation shows the formation of sulfur dioxide.S + O2 SO2How many moles of sulfur are needed to produce 15.0 mol of sulfur dioxide?

15.0 mol

The chemical equation below shows the formation of aluminum oxide (Al2O3) from aluminum (Al) and oxygen (O2).4Al + 3O2 2Al2O3The molar mass of O2 is 32.0 g/mol. What mass, in grams, of O2 must react to form 3.80 mol of Al2O3.

182 grams

Consider the balanced equation below. What is the mole ratio of PCl3 to PCl5?

1:1

Consider the equation below.Zn + H2SO4 ZnSO4 + H2The mole ratio of zinc to zinc sulfate is

1:1.

A chemist who is performing this reaction starts with 160.1 g of NH4NO3. The molar mass of NH4NO3 is 80.03 g/mol; the molar mass of water (H2O) is 18.01 g/mol. What mass, in grams, of H2O is produced?

72.06 grams

Consider the reaction below.2Al2O3 4Al + 3O2How many moles of oxygen are produced if 11.0 mol of Al are produced?

8.25 mol

Which proportionality shows the result of combining Avogadro's law with Boyle's law?

B

Which statement best explains the purpose of using a mole in the measurement of matter?

It allows chemists to deal with a large number of atoms.

Consider the substances below. • 1 mol of beryllium • 1 mol of salt • 1 mol of water • 1 mol of hydrogen Which statement is true about these substances?

They have different masses.

The mass and volume of each sample differ from the mass and volume of the other samples. Is it possible for each sample to contain 1 mol of each substance?

Yes, if each sample contains 6.02 x 1023 atoms.

A chemical equation can be used to solve stoichiometry problems provided that it

includes the coefficients that are needed for balancing the equation.

The ideal gas constant, R has several different values that could be used. Which quantity causes these differences?

pressure