General Chemistry 1 lab final exam

molar mass

the mass of one mole of a pure substance

how to use molar mass

mass/molar mass

synthesis reaction

A+B->AB

decomposition reaction

AB->A+B

single replacement reaction

AB+C->B+AC

double replacement reaction

AB+CD->AC+BD

precipitation

(aq)+(aq)->(s)+(aq)

combustion reaction

x+O2->CO2+H2O

acid-base reaction

A+B->H2O+C

molarity equation

M = moles of solute/liters of solution

percent composition

(mass of element/molecular mass) * 100

lab 1 pennies

calculated density of pre and post 1982 pennies

lab 1 glassware used

plastic graduated cylinder

density equation

density=mass/volume

water displacement method

a method that involves putting an object into water and carefully recording how much the water level rises

lab 2 hydrocarbons

observe the physical and chemical properties of different hydrocarbons.

alkane compound

a hydrocarbon containing only single covalent bonds

alkene compound

C=C double bond

aromatic compound

a compound that contains the ring structure of benzene

lab 4 copper

observe a type of reaction involving isolation of copper while exploring the concepts of solubility.

precipitate

A solid that forms from a solution during a chemical reaction.

supernatant

Clear liquid remaining after sediment settles

theoretical yield

the maximum amount of product that can be produced from a given amount of reactant

percent yield

actual yield/theoretical yield x 100

lab 3 calcium phosphate

synthesize calcium phosphate and determine percent yield

limiting reagent

any reactant that is used up first in a chemical reaction; it determines the amount of product that can be formed in the reaction

lab 5 hydrogen peroxide

determine the concentration of a commercial sample of hydrogen peroxide solution

lab 5 glassware

250 mL Erlenmeyer flask
50 mL buret
25 mL graduated cylinder

titration

A solution of known concentration is used to determine the concentration of another solution.

titrant

a solution of known concentration

analyte

Substance being analyzed

equivalence point

the point at which the two solutions used in a titration are present in chemically equivalent amounts

end point

the point in a titration at which an indicator changes color

color change hydrogen peroxide

light pink

lab 6 antacids

determine the mass of hydrochloric acid (HCl) neutralized per gram of one of two antacids

back titration

Method where an excess of a reagent is reacted with a sample. The unreacted reagent is then determined by titration.

color change antacid

iridescent yellow end pt

lab 7 Boyles law

use a gas pressure sensor and a syringe to measure the pressure of an air sample

hess' law def

the overall enthalpy change in a reaction is equal to the sum of enthalpy changes for the individual steps in the process

calorimeter

a measuring instrument that determines quantities of heat

lab 8 hess's law

use a foam cup calorimeter to measure the heat released by 3 reactions

thermal equilibrium

when two objects are at the same temperature and no heat flows

why is calculating the MM of air hard?

because air is not a single compound, but rather a mixture of various gases like nitrogen, oxygen, argon, and carbon dioxide, each with its own molar mass

most abundant gases in the atmosphere

nitrogen and oxygen

real gas law equation

(P + an2 /V2 )(V-nb) = nRT.

What is the formula for density?

d=v/m

d=m/v

d=2mv

d=πr^2h

d=m/v

How do you get an accurate reading when measuring the volume of water in a graduated cylinder? (Select all that apply.)

by reading the meniscus at eye level 

by reading the highest point of the meniscus 

by reading the bottom of the meniscus  

by reading the meniscus from above

by reading the meniscus at eye level 

by reading the bottom of the meniscus

T/F: The composition of the penny changed in 1928.

True

False

false (it changed in 1982)

What is the first step in Experiment 1?

Calculate the volume from a mass measurement and a given density 

Calculate the density of the post-1982 penny 

Calculate the volume of a penny using a ruler 

Measure the volume of a penny by using water displacement 

Calculate the volume of a penny using a ruler 

T/F: To determine the final volume of a penny using water displacement, you would subtract the final volume from the initial volume (Vi - Vf). 

True

False

False

What are the three types of hydrocarbons investigated during Experiment 2?

Alkanes, Alcohols, and Aldehydes

Esters, Ethers, and Alcohols

Amides, Aldehydes, and Alkenes

Alkanes, Alkenes, and Aromatic compounds

Alkanes, Alkenes, and Aromatic compounds

Why is an alkane considered to be a saturated hydrocarbon?

Because it contains only triple bonds between carbon atoms

Because it contains only double bonds between carbon atoms

Because it contains all types of bonds between carbon atoms

Because it contains only single bonds between carbon atoms

Because it contains only single bonds between carbon atoms

T/F: Aromatic compounds are relatively unreactive.  

True

False

true

Which hydrocarbon reacts with potassium permanganate (KMnO₄) to form a diol?

Alkenes

Alkanes 

None of the above

Aromatic compounds

alkenes

alkane

alkene

aromatic

What are the correct stoichiometric coefficients for the following chemical reaction?

CaCl₂(aq) + Na₃PO₄(aq) ---> NaCl(aq) + Ca₃(PO₄)₂(s)

3CaCl₂(aq) + 2Na₃PO₄(aq) ---> 1NaCl(aq) + 6Ca₃(PO₄)₂(s)

6CaCl₂(aq) + 3Na₃PO₄(aq) ---> 2NaCl(aq) + 1Ca₃(PO₄)₂(s) 

4CaCl₂(aq) + 3Na₃PO₄(aq) ---> 1NaCl(aq) + 2Ca₃(PO₄)₂(s)

3CaCl₂(aq) + 2Na₃PO₄(aq) ---> 6NaCl(aq) + 1Ca₃(PO₄)₂(s)

3CaCl₂(aq) + 2Na₃PO₄(aq) ---> 6NaCl(aq) + 1Ca₃(PO₄)₂(s)

T/F: Calcium phosphate can be synthesized from calcium chloride and sodium phosphate in a single displacement reaction.

True

False

false

What is the purpose of the vacuum filter in Experiment 5? 

to activate the chemical reaction 

to isolate the precipitate from the solution 

to add a specific amount of water to the solution 

to cool the solution to a particular temperature

to isolate the precipitate from the solution

T/F: The form of calcium phosphate found in teeth and bones is called apatite.  

True

False

true

CaCl₂

110.98 g/mol             

Na₃PO₄  ^.  12H₂O         

380.12 g/mol  

Ca₃(PO₄)₂          

310.18 g/mol  

What is the overall chemical reaction when copper (II) sulfate reacts with magnesium metal?

CuSO₄(aq) + Mg(s) ---> MgSO₄(aq) + Cu(s)

CuSO₄(aq) + Mg(s) --->  MgCu(s) + SO₄(aq)

MgSO₄(aq) + Cu(s) ---> CuSO₄(aq) + Mg(s)

MgSO₄(aq) + Cu(s) ---> CuSO₄(aq) + Mg(s)

CuSO₄(aq) + Mg(s) ---> MgSO₄(aq) + Cu(s)

What is the formula for percent yield?

Percent yield = (actual yield / theoretical yield) x 100% 

Percent yield = (theoretical yield / actual yield) x 100%

Percent yield = (actual yield / theoretical yield)

Percent yield = (theoretical yield / actual yield)

Percent yield = (actual yield / theoretical yield) x 100% 

What is the stoichiometric ratio between copper sulfate (CuSO₄) and copper metal (Cu)?

2 mol CuSO₄ = 1 mol Cu 

1 mol CuSO₄ = 2 mol Cu 

3 mol CuSO₄ = 1 mol Cu 

1 mol CuSO₄ = 1 mol Cu

1 mol CuSO₄ = 1 mol Cu

What is added to dissolve the solid magnesium (Mg) that did not react with the copper sulfate (CuSO₄)?

Nitric acid (HNO₃) 

Hydrobromic acid (HBr)

Hydrochloric acid (HCl)

Sulfuric acid (H₂SO₄)

Sulfuric acid (H₂SO₄)

T/F: When metals are ionized, they become insoluble in water and precipitate. 

True

False

false

Which of the following are true at the equivalence point of a titration? (Select all that apply)

The resulting solution turns colorless 

All of the H₂O₂ has completely reacted

The resulting solution turns pink 

All of the KMnO₄(aq) has completely reacted

The resulting solution turns colorless

All of the H₂O₂ has completely reacted

In Experiment 6, how do you know the end point has been reached in the titration? 

The solution turns a faint yellow color

The solution turns a faint blue color 

The solution turns colorless 

The solution turns a faint pink color

The solution turns a faint pink color

What is the stoichiometric ratio between KMnO₄(aq) and H₂O₂(aq)? Refer to the chemical equation if needed.

3:4

2:5

5:3

1:5

2:5

What is the titrant used in this experiment? 

KMnO₄ 

H₂O₂

O₂

MnSO₄

KMnO₄ 

At the beginning of the experiment, what solution is in the buret? What solution is in the Erlenmeyer flask?

Buret - hydrogen peroxide solution

Erlenmeyer flask - H₂O

Buret - aqueous potassium permanganate

Erlenmeyer flask - hydrogen peroxide solution 

Buret - H₂O

Erlenmeyer flask - hydrogen peroxide solution  

Buret - hydrogen peroxide solution

Erlenmeyer flask - aqueous potassium permanganate

Buret - aqueous potassium permanganate

Erlenmeyer flask - hydrogen peroxide solution 

T/F: In this experiment, the dissolved antacid will be directly titrated with HCl (aq).

True 

False

false

How does an antacid neutralize the excess stomach acid?

The antacid acts as a base to accept protons

The antacid acts as a base to donate protons 

The antacid acts as an acid to accept protons 

The antacid acts as an acid to donate protons

The antacid acts as a base to accept protons

What is added to the analyte to indicate the end point? (exp. 6)

Methyl orange

Phenolphthalein 

Potassium permanganate 

Methyl red 

Methyl orange

What is the titrant used in this experiment?

NaOH

HCl 

KMnO₄ 

Antacid mixture

NaOH

What color will appear in solution when the end point is reached?

Red

Yellow

Pink

Orange

Yellow

Boyle's Law relates which two variables for a confined gas?

enthalpy and entropy

volume and temperature

enthalpy and pressure

pressure and volume

pressure and volume

What is assumed to remain constant throughout the experiment?

temperature

pressure

volume

all of the above

temperature

What gas will be confined in the syringe? (exp 7)

argon

air

oxygen

carbon dioxide

air

What is purpose of the Gas Pressure Sensor?

to monitor the change in volume

to monitor the change in pressure 

to monitor the change in termperature 

to monitor the change in volume, temperature, and pressure

to monitor the change in pressure 

For this experimental setup, how do you get an accurate total volume when reading the syringe?

You subtract 0.8mL from the volume contained in the syringe

You multiply 0.8 mL times the voulme contained in the syringe.

You divide 0.8mL form the volume contained in the syringe. 

You add 0.8mL to the value contained in the syringe

You add 0.8mL to the value contained in the syringe

What is used as a calorimeter in Experiment 8, Hess's Law?

A polystyrene foam cup in a beaker

A plastic cup in a beaker

A glass cup in a beaker

A copper metal cup in a beaker

A polystyrene foam cup in a beaker

What do solid sodium hydroxide and aqueous hydrochloric acid react to form? (Select all that apply)

H₂(g)

Cl^-(aq)

NaOH(s)

 H₂O(l)

Na⁺(aq) 

Cl^-(aq),  H₂O(l), Na⁺(aq)

T/F: The heat lost to the calorimeter and the surrounding air has a large effect on the results and should be considered in the calculations.  

True

False

False

Why is it important to weigh the solid sodium hydroxide and proceed to the next step without delay?

Because solid sodium hydroxide picks up moisture from the air

All of the above 

Because solid sodium hydroxide produces toxic fumes 

Because solid sodium hydroxide can quickly turn into a liquid

Because solid sodium hydroxide picks up moisture from the air

In this experiment, on of the reactions performed is the same as the combination of the other two reactions. According to Hess's Law, the heat of reaction of the one reaction should be equal to ...

the sum of the heats of reaction for the other two reactions

the difference of the heats of reaction for the other two reactions 

the product of the heats of reaction for the other two reactions

the first heat of reaction divided by the second heat of reaction

the sum of the heats of reaction for the other two reactions

T/F: Air is not a single pure gas, but a homogeneous mixture of several different gases.

 True

False

true

What is the ideal gas equation?

Pn=VRT

Vn=PRT

PV=nRT

VT=nPR

PV=nRT

How is the molar mass of the air determined in this experiment?

the ratio of the mass that is lost to the change in the number of moles in the flask 

MM = ∆m / ∆n

MM = ∆n / ∆m

the ratio of the change in the number of moles in the flask to the mass that is lost

the ratio of the mass that is lost to the change in the number of moles in the flask 

MM = ∆m / ∆n

T/F: In this experiment, you will be directly measuring the mass of the air. 

True

False

false

What are the units for temperature in the ideal gas law?

All of the above

Fahrenheit 

Celsius 

Kelvin 

Kelvin