Solutions Unit - Incomplete

Question 0

What is matter?
What are pure substances?
What are mixtures?

Answer 0

Matter is any solid, liquid, or gas that has mass and volume
Pure substances are a type of matter that has definite fixed composition
Mixtures are combinations of matter that can be separated by physical means and do not have definite proportions

Question 1

Classify matter

Answer 1

All matter is made up of mixtures and pure substances. pure substances are elements and compounds. mixtures are heterogeneous and homogenous

Question 2

What are heterogeneous mixtures?

What are solutions?

Answer 2

Heterogeneous mixtures have varying composition and the different components are usually visible
Solutions are homogeneous mixtures that have uniform composition and the different components are not visible
Solutions are composed of at least one substance dissolved in another

Question 3

What is solvent? What is solute?

Answer 3

Solvent is the dissolver and is usually present in the largest quantity
Solute is what is dissolved in the solvent

Question 4

What is the solvent in an aqueous solution?

Answer 4

Water

Question 5

Pros and cons of water dissolving a lot of solutes

Answer 5

The pros are that 75% of the earth and our bodies is water

The cons are that toxins dissolve in it easily

Question 6

What is the responsible care program?

Answer 6

Set up in Canada in 1985 to ensure that companies that deal with chemicals are using them in a safe and appropriate manner

Question 7

What is biomagnification (bioaccumulation)?

Answer 7

The increase in the concentration of toxins as you move up the food chain

Question 8

What is concentration? What does dilute mean? What does concentrated mean?

Answer 8

Concentration is the amount of solute relative to the amount of solvent
Dilute = low solute, high solvent
Concentrated = high solute, low solvent

Question 9

How can you express concentration?

Answer 9

ppm, ppb, ppt, % mass, % volume, mol/L, mmol/L, mg/dL,%

Question 10

What is molarity?

What are the formulas for molarity?

Answer 10

The number of moles of solute per liter of solvent
c=n/v Where c=concentration, v=volume in L, n= moles
n=m/M Where n=moles, m=mass in g, M=molar mass in g/mol

Question 11

What is a standard solution?

Answer 11

A solution of known concentration

Question 12

What are two ways to make a solution?

Answer 12

Dissolve a measured amount of pure solute in a certain volume of solvent
Dilute a standard solution

Question 13

How do you prepare a solution of known concentration from a solid solute?

Answer 13

1. Measure_G (mass) of_(solute)
2. Dissolve the solute in_mL of water (half of the volume)
3. Transfer the solution to a_mL Volumetric flask
4. Fill flask to_mL (final volume) and mixed by inverting

Question 14

What is dilution?

What is the formula used?

Answer 14

Decreasing the concentration of a solution by adding more solvent
ViCi=VfCf
Ni=Nf
*Vi always smaller than Vf
*Ci always bigger than Cf

Question 15

Is dissolving a physical or chemical change?

What happens to the bonds in a solute when being dissolved?

Answer 15

Physical

The bonds break and the ions or molecules of the solute become attracted to the solvent particles

Question 16

What are the three processes involved in dissolving?

Answer 16

1. bonds broken between molecules or ions of solute – always endothermic (requires energy)
2. bonds broken between molecules of solvent – always endothermic
3. bonds formed between molecules or ions of solute insolvent – always exothermic

Question 17

What are electrolytes? What are non-electrolytes?

Answer 17

Electrolytes are aqueous solutions that conduct electricity

Non-electrolytes are aqueous solutions that do not conduct electricity

Question 18

What is disassociation?

What are disassociation equations used for?

Answer 18

Occurs when ionic compounds break apart into their ions when they are dissolved in an aqueous solution
Disassociation equations are used to show what happens to a substance when put in water

Question 19

What are the four situations for disassociation equations?

Answer 19

1. insoluble ionic or molecular compounds – They do not dissolve, use the solubility table for ionic compounds
2. soluble ionic compounds – dissolve to form ions in solution, ionic bonds are broken, use solubility table, includes bases, balance the number of ions
3. soluble molecular compounds – dissolved for molecules in solution, intermolecular forces are broken
4. acids - molecular compounds but very polar, dissolve to form ions in solution, balance the number of ions