Chem test 2

Question 1

where do the most common and most important chemical reactions take place in?

Answer 1

Water

Question 2

Define solution

Answer 2

homogeneous mixture of two or more substances

Question 3

define solvent

Answer 3

major component of the mixture (water)

Question 4

define solute

Answer 4

minority component of the mixture

Question 5

how many carbons in an alcohol does it take to become insoluble in water?

Answer 5

5 carbons

Question 6

What does the solubility of one substance in another depend on?

Answer 6

intermolecular forces (like dissolves like)
- between the solvent and solute
-between the solvent particles
-between the solute particles

More polar substances dissolve better in water because water is polar

Question 7

define saturated

Answer 7

the point where the max amount of solutes have dissolved. if you add more they won’t dissolve

Question 8

define unsaturated

Answer 8

a solution in which the solvent holds less than the max solute. if you add more they will dissolve

Question 9

define supersaturated

Answer 9

a solution in which the solvent holds more than the max amount of solute dissolved (usually unstable)

this happens if you heat a saturated mixture and add more solute. when it is cooled it will stay dissolved and be supersaturated

Question 10

How to find the molecular weight of something

Answer 10

add the mass of each atom in your compound

Question 11

How to calculate for mols

Answer 11

Mass of sample (g) / molecular weight (g/mol)

Question 12

How many moles are in a 10g sample of water? molecular weight is 18.02

Answer 12

10g/18.02g/mol = 0.555mol

Question 13

Density equals

Answer 13

mass over volume

Question 14

how to describe the amount of solute in a solution by molarity:

Answer 14

mol/L

Question 15

how to describe the amount of solute in a solution by weight percent:

Answer 15

mass/mass X 100%

Question 16

how to describe the amount of solute in a solution by volume percent:

Answer 16

volume/volume X 100%

Question 17

a solution concentration expressed in moles of solute/kg of solvent will be presented as _____
This type is independent of ______ but can change depending on the ________ of the solvent

Answer 17

weight/weight

independent of temperature but can change depending on the density of the solvent

Question 18

What is the process to solve for a molality weight weight problem?

Answer 18

g (solute) -> moles (solute) -> molality (solution)

Question 19

When is the weight percent useful?

Answer 19

When the solute is a solid

Question 20

define weight percent

Answer 20

solution concentration expressed as a percentage of the solute mass in the mass of solution

Question 21

define volume percent

Answer 21

solution concentration expressed as a percentage of the solute volume in the volume of the solution

Question 22

When is the volume percent useful?

Answer 22

when the solute is a liquid

Question 23

how much ethanol is in a 10mL sample of 85% aqueous ethanol?

Answer 23

(85mL/100mL) X 10mL

Question 24

how much NaCl is in a 25g sample of 0.900% saline solution?

Answer 24

(0.900g NaCl/100G) X 25g