Solutions and Solubility pt 1

Question 1

What is the law of conservation of matter?

Answer 1

Summarizes scientific observations about matter by stating that there is not detectable change in the total quantity of matter present when matter converts from one type to another (chemical change) or changes among solid, liquid, or gaseous states (physical change)

Question 2

What can be true according to the law of conservation of matter?

Answer 2

Matter is neither created nor destroyed (must have same number and type of atoms)

Question 3

When atoms gain or lose electrons to yield ions or combine with other atoms to form molecules, what is true of their symbols?

Answer 3

Symbols are modified or combined to generate chemical formulas that appropriately represent these species

Question 4

What does a chemical equation symbolize?

Answer 4

Acts as symbolism to represent both the identities and the relative quantities of substances undergoing a chemical (or physical) change

Question 5

What are reactants?

Answer 5

Substances undergoing reaction on the left side

Question 6

Where are reactants found in a chemical equation?

Answer 6

Left side

Question 7

What are products?

Answer 7

The substances generated by the reaction on the right

Question 8

Where are products found in a chemical equation?

Answer 8

Right side

Question 9

Plus signs do what in a chemical equation?

Answer 9

Separate individual react and product formulas

Question 10

The arrow does what in a chemical equation?

Answer 10

Separates the react and product (left and right) sides of the equation

Question 11

What is the purpose of coefficients in a chemical equation?

Answer 11

Numbers placed immediately to the left of each formula to act as the relative numbers of reactant and product species

Question 12

What is a balanced equation?

Answer 12

The equal numbers of atoms for each element involved in the reaction are represented on the reactant and product sides

Question 13

Formula subscripts do what to a chemical equation?

Answer 13

Formula subscripts define and maintain the identity of the substance, therefore they cannot be changed

Question 14

True or False: It is important for the charge to be balanced on both the reactant and product sides in a balanced equation

Answer 14

True

Question 15

Write a balanced equation for the decomposition of ammonium nitrate to form molecular nitrogen, molecular oxygen, and water.

Answer 15

2 NH4NO3 ⟶ 2 N2 + O2 + 4 H2O

Question 16

True or False: It is sometimes convenient to use fractions instead of integers as intermediate coefficients in the process of balancing a chemical equation.

Answer 16

True

Question 17

True or False: When balance is achieved, all the equation’s coefficients may then be multiplied by a whole number to convert the fractional coefficients to integers without upsetting the atom balance.

Answer 17

True

Question 18

True or False: It is common practice to use the smallest possible whole-number coefficients in a chemical equation

Answer 18

True

Question 19

What are common abbreviations for the physical states of reactants and products?

Answer 19

s for solids, l for liquids, g for gases, and aq for substances dissolved in water (aqueous solutions)

Question 20

What are solutions?

Answer 20

homogeneous mixtures of two or more substances

Question 21

What is a solvent?

Answer 21

one component of a solution is present at a significantly greater concentration

Question 22

What are the remaining components without the solvent called?

Answer 22

Solutes

Question 23

What are solutes

Answer 23

The other components of the solution present in relatively lesser concentrations

Question 24

True or False: Water is used so often as a solvent that the word solution has come to imply an aqueous solution to many people. However, almost any gas, liquid, or solid can act as a solvent.

Answer 24

True

Question 25

What are some defining traits of solutions?

Answer 25

They are homogeneous; that is, after a solution is mixed, it has the same composition at all points throughout (its composition is uniform). The components of a solution are dispersed on a molecular scale; that is, they consist of a mixture of separated molecules, atoms, and/or ions. The dissolved solute in a solution will not settle out or separate from the solvent.

Question 26

What occurs when ionic compounds dissolve in water?

Answer 26

the ions in the solid separate and disperse uniformly throughout the solution because water molecules surround and solvate the ions, reducing the strong electrostatic forces between them

Question 27

True or False: Water and other polar molecules are attracted to ions

Answer 27

True

Question 28

What is an ion-dipole attraction?

Answer 28

The electrostatic attraction between an ion and a molecule with a dipole

Question 29

What are electrolytes?

Answer 29

Substances that produce ions in solutions when they dissolve

Question 30

What are nonelectrolytes?

Answer 30

Substances that do not yield ions when dissolved

Question 31

How can substances be identified as strong, weak, or non-electrolytes?

Answer 31

by measuring the electrical conductance of an aqueous solution containing the substance

Question 32

True or False: Solutions may also conduct electricity if they contain dissolved ions, with conductivity increasing as ion concentration increases.

Answer 32

True

Question 33

True or False: Electrolytes (such as salts) conduct electricity when dissolved in water

Answer 33

True

Question 34

True or False: non-electrolytes (such as sugar and ethanol) do not conduct electricity when dissolved in water

Answer 34

True

Question 35

What is the definition of a balanced equation?

Answer 35

chemical equation with equal numbers of atoms for each element in the reactant and product

Question 36

What is the definition of a chemical equation?

Answer 36

symbolic representation of a chemical reaction

Question 37

What is the definition of a coefficient?

Answer 37

number placed in front of symbols or formulas in a chemical equation to indicate their relative amount

Question 38

What is the definition of a product?

Answer 38

substance formed by a chemical or physical change; shown on the right side of the arrow in a chemical equation

Question 39

What is the definition of a reactant?

Answer 39

substance undergoing a chemical or physical change; shown on the left side of the arrow in a chemical equation

Question 40

What does it mean to say an equation is balanced? Why is it important for an equation to be balanced?

Answer 40

To say you have a balanced equation means you have an equal number of total atoms on the reactant and product side of the reaction. This is important since the law of conservation has to be applied; no matter is lost throughout the reaction

Question 41

Why are most solid ionic compounds electrically nonconductive, whereas aqueous solutions of ionic compounds are good conductors? Would you expect a liquid (molten) ionic compound to be electrically conductive or nonconductive? Explain

Answer 41

Most solid ionic compounds have neutral charge, and so there are no electrolytes able to conduct charge. Aqueous solutions of ionic compounds are good conductors because they dissociate to form ions (atoms with charge), which are good electrolytes. One would expect a liquid (molten) ionic compound to conduct electricity because the ions are free to move more in a liquid state than a solid state, and thus, able to allow electricity to flow.

Question 42

What are the basic steps in balancing chemical equations?

Answer 42

1. Change coefficients not subscripts 2. Label the states of matter and other reaction conditions 3. Make sure quantities and charges are balanced

Question 43

What is a precipitation reaction?

Answer 43

Type of aqueous reaction/solution that discusses issues of solubility (if compounds are soluble or not)

Question 44

If a compound is soluble, what is it considered?

Answer 44

Strong electrolyte

Question 45

If a compound is not soluble, what is it considered?

Answer 45

Non-electrolyte

Question 46

True or False: Soluble ionic compounds are electrolytes

Answer 46

True

Question 47

True or False: Molecules other than acids/bases tend not to be electrolytes

Answer 47

True

Question 48

Strong electrolytes dissociate entirely into?

Answer 48

Soluble ionic compounds, strong acids

Question 49

Weak electrolytes dissociate entirely into?

Answer 49

Weak acids, weak bases

Question 50

When does a precipitation reaction occur?

Answer 50

When two aqueous solutions are mixed to form an insoluble product

Question 51

What is true of NH4+ and alkali metal ions?

Answer 51

They are always soluble

Question 52

What is true of NO3- and CH3COO-?

Answer 52

They are always soluble

Question 53

What is true of Cl-, Br-, and I-?

Answer 53

They are usually soluble, but are not soluble with Ag+, MgHg22+, Pb2+

Question 54

What is true of CO32-, PO43-?

Answer 54

They are usually insoluble

Question 55

What is another term to refer to precipitation reactions as and why?

Answer 55

"Exchange or metathesis reaction" because it seems as if ax + by --> ay + bx