Cumulative Exam Semester II Review

Which statement is true at STP? (The atomic mass of Mg is 24.31 u.)

(3 mc013-3.jpg 24.31) g of Mg produce (3 mc013-4.jpg 22.4) L of H2 gas.

A 150 mL sample of hydrochloric acid (HCl) completely reacted with 60.0 mL of a 0.100 M NaOH solution. The equation for the reaction is given below. HCl + NaOH mc011-1.jpg NaCl + H2O What was the original concentration of the HCl solution?

0.040 M

The molar mass of KCl is 74.55 g/mol. If 8.45 g KCl are dissolved in 0.750 L of solution, what is the molarity of the solution?

0.151 M

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

The molar mass of water (H2O) is 18.0 g/mol. A sample of water has a mass of 18.0 g. How many moles of water are contained in this sample?

1.00

The chemical equation below shows the formation of aluminum oxide (Al2O3) from aluminum (Al) and oxygen (O2). 4Al + 3O2 mc029-1.jpg 2Al2O3 The 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

The pH of lemon juice at 298 K is found to be 2.32. What is the concentration of mc014-1.jpg ions in the solution?

4.79 x 10-3M

The chemical equation below shows the decomposition of ammonium nitrate (NH4NO3). NH4NO3 mc018-1.jpg N2O + 2H2O 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

Which statement best describes the process that the diagrams show? The diagrams show the particles of a substance.

A solid gains kinetic energy to become a liquid and then becomes a gas.

Which diagram is a bomb calorimeter?

B

An ice cube is dropped into a glass of milk at 20°C. Which statement explains the transfer of kinetic energy (KE)?

Because milk has higher KE than ice, KE is transferred from the milk to the molecules of ice.

Which law is described by saying that when the pressure of a gas in a sealed container is cut in half, the gas will double in volume at a steady temperature?

Boyle's law

Which statement best explains the change that occurs when gas particles move more slowly?

The temperature decreases because the average kinetic energy decreases.

The gases listed are at standard temperature and pressure: · 1 mol of CO2 gas · 1 mol of N2 gas · 2 mol of O2 gas Which statement is correct?

The volumes of 1 mol of CO2 and 1 mol of N2 gases are the same.

Shana solves stoichiometry problems using the equation for the synthesis of water. mc029-1.jpg Which interpretation of the balanced equation would cause Shana to make a mistake?

Two grams of hydrogen react with one gram of oxygen to form two grams of water.

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

V - n/P

Brownian motion is not observed in a mixture that includes two phases. Which best identifies the mixture?

a suspension

When ammonium chloride is dissolved in water, the beaker gets cold. Which type of reaction does this describe?

endothermic

In the diagram below, particles of the substance are moving from the liquid phase to the gas phase at the same rate as they move from the gas phase to the liquid phase.

equilibrium.

The diagrams show gases that are stored in two separate but similar containers. If both gases are at the same temperature, which one has the greater pressure?

gas 2 because it has more particles that are colliding

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

pressure

Which defines the average kinetic energy of a system's particles?

temperature

The overall change in enthalpy of a reaction depends only on

the reactants and the products.

According to Hess's law, if a series of intermediate reactions are combined, the enthalpy change of the overall reaction is

the sum of the enthalpy changes of the intermediate reactions.

Why is citric acid added to food?

to add tartness