Gases
What happens to the pressure of a gas if the volume decreases while temperature stays constant?
The pressure increases
According to the Bronsted-Lowry definition, what does a base do?
A base accepts a proton (H⁺)
What is the difference between a solute and a solvent?
A solute is the substance being dissolved, and a solvent is the substance doing the dissolving.
What is a chemical equilibrium?
When the forward and reverse reactions happen at the same rate.
What type of reaction absorbs heat from its surroundings?
Endothermic
What relationship exists between pressure and volume in Boyle’s Law?
They are inversely proportional.
What are the products of a neutralization reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH)?
Water (H₂O) and sodium chloride (NaCl).
What type of mixture has a uniform composition throughout?
A homogeneous mixture.
At equilibrium do reactions stop completely?
No, both reactions continue at equal rates.
What happens to the particles in a substance when thermal energy is added?
The particles move faster and spread farther apart.
A gas occupies 15 L at 1.2 atm. If the pressure changes to 3.0 atm, what will the new volume be?
6 L
When NH₃ accepts a proton to become NH₄⁺, what is NH₄⁺ called?
The conjugate acid of NH₃.
If more solute is added to a solution than can dissolve, what type of solution is formed?
A saturated solution.
According to Le Chatelier’s Principle, what happens if more reactant is added to a system at equilibrium?
The system shifts to the right to produce more products.
Which substance would heat up faster if the same amount of heat is added: a substance with high specific heat or low specific heat?
A substance with low specific heat.
A gas sample has a volume of 24 L at a pressure of 1.5 atm. If the volume is decreased to 8 L, what will the new pressure be? Show how Boyle’s Law explains this change.
4.5 atm. Since the volume became 3 times smaller, the pressure became 3 times larger because pressure and volume are inversely related.
A solution has a pH of 3. Is the hydrogen ion concentration high or low, and is the solution acidic or basic?
The hydrogen ion concentration is high, and the solution is acidic.
Why does sugar dissolve faster in hot water than in cold water?
Because higher temperatures increase particle movement, causing faster dissolving.
What does a large equilibrium constant (K) tell you about a reaction?
The reactions favor products.
Why does temperature stay constant during a phase change even when heat is still being added?
The added energy is used to change the state of matter instead of increasing temperature.
A scuba diver has an air bubble with a volume of 10 L at a pressure of 5 atm underwater. As the diver rises, the pressure decreases to 2 atm. What is the new volume of the bubble, and why could this be dangerous?
25 L. When pressure decreases, the gas expands. This can be dangerous because expanding gases can damage the lungs or cause pressure-related injuries if the diver rises too quickly.
During a titration, 25 mL of HCl is completely neutralized by 25 mL of 1.0 M NaOH. What is the molarity of the HCl solution?
1.0 M HCl
A student mixes sand and salt in water. Which process should be used first to separate the sand from the mixture, and why?
Filtration should be used first because the sand does not dissolve in water.
A reaction at equilibrium has heat added to it and shifts left. What can you conclude about the forward reactions? Explain.
The forward reaction is exothermic because adding heat causes the system to shift in the opposite direction to reduce the added heat.
A sample of water is heated from ice to steam. Describe the energy changes that happen during melting and boiling.
During melting and boiling, energy is absorbed to overcome intermolecular forces and change the state of matter.