States of Matter
What are the three basic states of matter?
Solid, liquid, and gas.
According to Boyle’s Law, what happens to pressure when volume decreases?
Pressure increases because gas particles collide with the container walls more frequently.
P1V1 = P2V2
What type of mixture has a uniform composition throughout?
A homogeneous mixture. Its components are evenly distributed.
What type of reaction releases heat energy?
An exothermic reaction. Heat is transferred from the system to the surroundings.
What pH value is considered neutral?
A pH of 7. Neutral solutions have equal concentrations of H⁺ and OH⁻ ions.
What is the phase change from liquid to gas called?
Vaporization. During this process, particles gain enough energy to enter the gas phase.
Which gas law explains why a balloon expands when heated?
Charles’s Law. As temperature increases, gas particles move faster and spread farther apart.
What term describes a substance that dissolves in water?
Soluble. A soluble substance can dissolve to form a solution.
What law states that energy cannot be created or destroyed?
The Law of Conservation of Energy. Energy can only be transferred or converted into another form.
What ion do acids produce in water?
Hydrogen ions (H⁺). In water, they are commonly present as hydronium ions (H₃O⁺).
Which intermolecular force is strongest: dispersion forces, dipole-dipole forces, or hydrogen bonding?
Hydrogen bonding. It occurs when hydrogen is bonded to highly electronegative atoms like oxygen, nitrogen, or fluorine.
Why must Kelvin be used in gas law calculations?
Kelvin is an absolute temperature scale based on molecular kinetic energy.
What is the formula for molarity?
Molarity equals moles of solute divided by liters of solution.
M = mol/L
Which has more thermal energy: a cup of hot tea or a bathtub of warm water?
A bathtub of warm water because it contains much more matter.
What are the products of a neutralization reaction?
Salt and water. Neutralization occurs when acids react with bases.
Why do gases expand to fill their containers?
Gas particles move freely in constant random motion and have very weak attractive forces between them.
A gas has a volume of 2.0 L at 300 K. What will its volume be at 600 K if pressure stays constant?
4.0 L. According to Charles’s Law, doubling the temperature doubles the volume.
What happens to concentration when more water is added to a solution?
The concentration decreases because the same amount of solute is spread through a larger volume.
What happens to temperature during a phase change?
The temperature remains constant because energy is used to break intermolecular forces.
What is the conjugate base of HCl?
Cl⁻. It forms when HCl donates a proton.
Why does ice float on liquid water?
Ice is less dense than liquid water because hydrogen bonds create an open crystal structure
A gas occupies 3.0 L at 1.0 atm. What volume will it occupy at 3.0 atm if temperature remains constant?
1.0 L. Boyle’s Law shows that pressure and volume are inversely related
A solution contains 10 g of salt and 50 g of water. What is the percent by mass of salt?
16.7%. Percent by mass is calculated by dividing solute mass by total solution mass and multiplying by 100.
Why does sweating cool the body?
Evaporation absorbs heat energy from the skin, lowering body temperature.
What color does blue litmus paper turn in an acidic solution?
Red. Litmus paper is an indicator used to identify acids and bases.