Test Chapters 13&14 (questions)

it is recommended not to shuffle questions while studying

What are 3 factors that affect the rate of evaporation?

temperature, surface area, type of molecule

How does temperature affect the rate of evaporation?

hotter=faster , cooler=slower

increasing temp = higher kinetic energy —> allows particles to escape

How does temperature affect the vapor pressure of a liquid?

increasing temp = more particles released = more collisions = more pressure

How does surface area affect the rate of evaporation?

greater area=faster , less area=slower

more area, more molecules are exposed to the air

How do the type of molecules affect the rate of evaporation?

nonpolar=faster , polar=slower

polar opposites attract, harder to break apart

Why did our water not boil at exactly 100°F?

in our location, we did not have exactly 101.3 kPa of pressure/not at sea level

What type of molecule has a higher boiling point but lower vapor pressure? Why?

Polar molecules

they have a positive and negative charge that creates a stronger attraction —> harder for molecules to break apart (boil&vaporize)

Why does water take so long to boil?

The water molecule is bent and polar = higher boiling point

What happens to a water’s temperature when it starts to boil?

it stays the same

Why does the temperature stay the same when water is boiling?

heat makes particles more exited —> they escape and turn into vapor

temp doesn’t rise because the heat energy is used for that phase change, not temp increase

Why does it take longer to cook food in water at high altitudes?

higher up = less atmospheric pressure

water boils at a lower temperature and food must be cooked longer

How does a pressure cooker work?

they do not allow vapor to escape

Why does food take less time to cook in a pressure cooker?

water boils at a higher temperature —> quicker cook time

What is the relationship between the Kelvin temperature of a substance and the average kinetic energy of its particles?

K temp gets hotter = particles speed up —> rise in kinetic energy

How are the pressure, temperature, and volume of a gas related?

the Combined Gas Law

pressure (P), volume (V), temperature (T)

As intermolecular forces of attraction strengthen, does the vapor pressure increase or decrease?

decrease

higher forces of attraction = harder for molecules to break apart and vaporize

Why is atmospheric pressure much lower on the top of a moutain than it is at sea level?

• gravity pulls air molecules towards earth’s surface

• you experience less air from the atmosphere pressing down on you

• thinner air (density decreases w altitude)

Why are gases easier to compress compared to a liquid and solid?

their molecules are far apart and there are weaker intermolecular forces

what factor influences the rate of diffusion?

molar mass

higher molar mass=diffuse slower

lower molar mass=diffuse faster