Science Quiz - Chapter 13 lesson 2 - Water Chemistry

Why do some substances dissolve in water and others don't?

Like dissolves like, water is polar, non-polar substances do not dissolve well in water.

Solution can exist in all 3 ____________.

states of matter.

Water is the universal _______________.

solvent

water is a ____________ compound.

covalent

cohesion

Water is good at sticking to other molecules (like itself)

adhesion

Water is good at sticking to other objects or substances (like the penny)

water is _______ molecule

polar

since water is polar it has one slightly ______________ charged end and one slightly _______________ charged end.

positive, negative (order doesn't matter).

Like dissolves like, so water can dissolve both ________ and ___________- subsatnces.

polar, ionic

1 teaspoon = ___ mL

5 mL

water has a high ______________.

specific heat

specific heat

how much energy it takes for the water to evaporate.

Water is naturally found in ________________________, this is one of the reasons why its so speical.

in all three phases (solid, liquid, gas).

Having positive and negative ends allows polar molecules to have special properties including the ability to ________________________ ________________________.

easily bond with other polar molecules.

Surface tension:

water molecules stick tightly together at the surface of a liquid/property allowing liquid to resist external force.

cohesion contributes to _______________________.

surface tension

Ice floats in water. Why?

because water becomes less dense when forzen.

soap is an example of this. it breaks surface tension.

Surfactants

Surfactants

are designed to break the surface tension.

why does alcohol evaporate quicker than water?

the attraction between the alcohol molecules is less than those of the water. In other words the water molecules don't want to let go of each other as much as the alcohol molecules do.

how does water dissolve salt if salt is ionic not polar?

salt is made up of both negatively and positively charged ions. Because of this the polar water molecules are attracted to the salt molecules (opposites attract) and pull the salt apart.

why does water dissolve sugar(sucrose)?

because sucrose is polar.

How is solubility measured?

by the number of
grams of a substance that dissolves in 100 mL of water at a particular temperature.

does temperature effect dissolving?

Yes.

Can liquids dissolve in liquids? If so how?

Yes. Alcohol can dissolve in water. Think, water is polar alcohol is too (though not very polar). Like dissolves like.

Can gas dissolve in a liquid? If so, how?

Yes. Bubbles of gas are not dissolving in the water. In soda tiny molecules of carbon dioxide (CO2) dissolves into water because it has a slight negative charge near the oxygen and a slight positive charge near the carbon. CO2 has a weaker attraction to water than sugar or salt, that's why if left uncapped soda can become flat.

How does the temperature of the gas affect its solubility? (Warmer vs. Cooler)

When soda is heated the CO2,(a gas), molecules move faster loosening the bonds between the water and CO2 causing the gas to escape faster.
The opposite happens if it is colder (concentration of carbon dioxide is greater when the soda is colder)

Can the action of dissolving cause the temperature of the solution to increase? If so, how?

Yes. When creating bonds energy is released as much as when breaking them. (bonds are created and destroyed when dissolving occurs).