Chemistry: Final Exam Review

What is 98K in degrees Celsius?

(Celsius = Kelvin - 273) Answer: -175 degrees Celsius

What is 25 degrees Celsius in Kelvins?

(Kelvin = Celsius + 273) Answer: 298K

Draw the Lewis Dot Structure for Carbon.

. . C . .

Draw the Lewis Dot Structure for Fluorine.

. : F : ..

Draw the Lewis Dot Structure for an atom of Neon in its ground state.

.. : Ne : ..

What is the symbol for a beta particle?

0 B -1

What is the temperature at absolute zero?

0 K (all molecular motion stops)

Balance the equation: C3H8 + O2 ---> CO2 + H2O

1 C3H8 + 3 O2 ---> 5 CO2 + 4 H2O

How many atoms are in 1 mole?

1 mole = 6.02 x 10^23 atoms/molecules

What is the volume occupied by 1 mole of a gas at STP?

1 mole of gas at STP = 22.4 L

C2H4 + 3 O2 ----> 2 CO2 + 2 H2O If you start with 45 grams of ethylene (C2H4), how many grams of carbon dioxide will be produced?

141.4 g CO2

Balance the equation: H2 + O2 -----> H20

2 H2 + O2 ----> 2 H20

How many valence electrons does aluminum have?

3

Mg + 2 HNO3 ---> Mg(NO3)2 + H2 If I start this reaction with 40.0 grams of magnesium and an excess of nitric acid (HNO3), how many grams of hydrogen gas will I produce?

3.3 g H2

Find the molar mass of Al2(SO4)3

342 g/mol

What is the symbol for an alpha particle?

4 He 2

How many valence electrons are in an atom of chlorine?

7

What is a hydrogen ion acceptor called?

A base.

How does a catalyst speed up a chemical reaction?

A catalyst speeds up a chemical reaction by finding an alternate pathway with a lower activation energy.

Is energy absorbed or released in an endothermic reaction?

Absorbed.

pH < 7 ; acid, base, or neutral?

Acid

Lemonade; acid or base?

Acid (tastes sour)

Tastes sour; acid or base?

Acid.

The monomers that make up proteins are what?

Amino acids are the monomers.

What is a hydrogen ion donor called?

An acid.

pH > 7 ; acid, base, or neutral?

Base

Ammonia, acid or base?

Base (drain cleaners are bases).

Soap; acid or base?

Base (tastes bitter)

Feels slippery; acid or base?

Base.

Tastes bitter; acid or base?

Base.

How does surface area influence reaction rate?

By increasing the surface area of reactant molecules, we are increasing the space or point of contact that these molecules have available to interact. This causes an increase in the rate of reaction.

Which of the following will not conduct electricity when dissolved in water: NaCl, NaOH, HCl, C6H12O6

C6H12O6 is a sugar that is covalently bonded. It does not conduct electricity. NaCl is a salt and an electrolyte (conducts electricity). NaOH is a strong base and therefore, strong electrolyte. HCl is a strong acid and strong electrolyte. *All salts, acids, and bases will conduct electricity.

If I decrease the concentration of reactant, what happens to the rate of reaction?

Decreasing concentration leads to less reactants available for collision. Therefore, reaction rate decreases.

Is fusion an endothermic or exothermic process?

Endothermic (going from solid --> liquid). Think about phase change diagram.

Define equilibrium.

Equilibrium is established when the rate of the forward reaction is equal to the rate of the reverse reaction.

What is the sign of delta H for an exothermic reaction?

Exothermic reactions release energy. The sign of delta H is negative.

When you touch a flask and it feels hot, is this an endothermic or exothermic process?

Exothermic; heat is being given off.

What causes gas pressure?

Gas molecules are constant motion and collide with the walls of their containers and with the surfaces that they come into contact with. This collision causes pressure.

Which of the following has the greatest freedom of movement: solids, liquids, gases?

Gases

Is condensation an endothermic or exothermic process?

Going from gas ---> liquid. This is exothermic.

Is vaporization endothermic or exothermic?

Going from liquid ---> gas. This is endothermic.

Is solidification endothermic or exothermic?

Going from liquid ---> solid. This is exothermic.

Identify the following as a metal, semimetal, transition metal, or nonmetal: H, C, K, Fe, Si

H - nonmetal C - nonmetal K - metal Fe - transition metal Si - semimetal

q=mc(delta)T ; What does "q" stand for?

Heat (kJ)

How does increasing temperature affect the rate of reaction?

Increasing temperature causes the kinetic energy to increase. Thus, molecules are moving faster and colliding more frequently. This causes the rate of reaction to incrase.

Given the reaction at equilibrium: 1/2 N2 (g) +1/2 O2 (g) + 21.6 kcal ---> NO (g) What will happen if temperature is increased?

Increasing temperature means heat is being added more to the left side (think mud slide). The reaction will shift right to form more NO.

Equal volumes of gases at STP have equal _____.

Moles.

Are noble gases reactive?

NO! They have a full octet of electrons. They do not want to react with anything.

Define STP.

Pressure = 1 atm or 101.3 kPa Temperature = 0 degrees Celsius or 273 K

q=mc(delta)T ; What does "c" stand for?

Specific heat capacity (J / g degrees C)

Define specific heat capacity.

The amount of heat required to raise 1g of a substance to 1 degrees Celsius.

Define Reaction Rate

The decrease in concentration of reactants or the increase in concentration of products with time.

Define activation energy.

The energy required to start a chemical reaction.

Define solvent.

The part of the solution in greater amount. (HINT: solvent is a bigger word than solute)

Define solute.

The part of the solution in less amount.

You have an acid that dissociates partially in solution. Is this a strong or weak acid?

Weak acids dissociate partially. Strong acids and bases dissociate (break apart) completely in water.

Define neutralization.

When an acid reacts with a base to form water and a salt. pH = 7.