CHEM EXAM 2

What is the Law of Conservation of Mass?

The total type and number of atoms in the reactants must equal the total type and number of atoms of the products; atoms are rearranged but not lost or gained.

What is the mass of 1 mole of Gold (Au)?

196.97 g

What is the mass of 1 mole of Chlorine (Cl2)?

70.9 g

What is the mass of 1 mole of Barium Nitrate (Ba(NO3)2)?

261.33 g

How many moles are in 8.0 grams of cream of tartar (KC4H5O6)?

0.043 mol

How many molecules are in 11.8 grams of fructose (C6H12O6)?

3.95 x 10^22 molecules

What is the balanced equation for the reaction of Fe2O3 and CO to produce Fe and CO2?

Fe2O3 (s) + 3CO (g) → 2Fe (s) + 3CO2 (g)

How many moles of CO are required to produce 3 moles of Fe?

4.5 moles CO

How many grams of CO2 will be produced from 2250 grams of Fe2O3?

1,856 g CO2

How many grams of iron ore (Fe2O3) are required to yield 1.5 kg of iron (Fe)?

2,143 g Fe2O3

What is the theoretical yield of SO3 when 5.4 g of SO2 reacts with 3.5 g of O2?

6.7 g SO3 produced

Is Pb(NO3)2 soluble in water?

Yes, it is soluble.

Is Mg3(PO4)2 soluble in water?

No, it is insoluble.

What is the precipitate formed when Sr(NO3)2 and K2SO4 are mixed?

SrSO4

At 50 °C, is a solution with 50 g of KBr in 100 g of water saturated, unsaturated, or supersaturated?

Unsaturated

Why are carbonated beverages best when consumed cold?

Gas solubility decreases with increased temperature and decreased pressure.

Which dissolves faster: a sugar cube in hot tea or granulated sugar in iced tea?

Granulated sugar in hot tea due to more surface area and higher temperature.

What are two examples of units used to represent the concentration of a solution?

m/m % (mass/volume percent) and v/v % (volume/volume percent)

How do you calculate the molarity of a solution?

Molarity (M) = moles of solute / liters of solution

What is the process of reverse osmosis?

Applying pressure greater than osmotic pressure to force water across a membrane, purifying it.

How does water's hydrogen bonding contribute to its high surface tension?

Surface molecules form strong H-bonds with other water molecules, unable to bond with nonpolar air.

What happens to water's density when it freezes?

Water expands and becomes less dense due to the crystal lattice structure formed by hydrogen bonds.

What are the general steps in municipal water treatment?

Coagulation, Filtration, Disinfection

How does distillation purify water?

Heating impure water to produce vapor, then cooling to condense it back into liquid.

What are the three definitions of acids according to different theories?

Arrhenius: Produce H+; Bronsted-Lowry: Donate H+; Lewis: e- pair acceptor.

What are the observable properties of acids?

Taste sour, sting to touch, corrode metal, react with CO32-, can denature proteins.

What are the observable properties of bases?

Taste bitter, slippery to touch, neutralize stomach acid.

What household items are examples of acids?

Citrus fruits, vinegar, toilet cleaner.

What household items are examples of bases?

Ammonia, detergents, drain/oven cleaner (lye), antacids.

What is the pH range for acids?

pH < 7.0.

What is the pH range for bases?

pH > 7.0.

What is the neutralization reaction between H3PO4 and NaOH?

H3PO4 (aq) + 3NaOH (aq) → 3H2O (l) + Na3PO4 (aq).

What is the conjugate base of HNO3 in the reaction with water?

NO3-.

What is the conjugate base of NH3 in the reaction with water?

OH-.

What does 'organic' mean in chemistry?

The study of carbon-containing molecules.

What is a hydrocarbon?

A molecule containing only carbon and hydrogen, which is nonpolar.

What type of bond allows carbon to form stable structures?

Carbon can form 4 stable bonds (single, double, or triple).

What are the three types of hydrocarbons?

Alkane (single bonds), Alkene (double bonds), Alkyne (triple bonds).

What is the balanced combustion reaction of pentane (C5H12)?

C5H12 + 8 O2 → 5 CO2 + 6 H2O.

What is the difference between cis- and trans- double bonds in alkenes?

Cis- has hydrogen on the same side; trans- has hydrogen on opposite sides.

What functional groups are present in a monosaccharide?

Ether and alcohol.

What functional groups are present in an amino acid?

Carboxylic acid and amine.

What functional group is formed when amino acids create a peptide bond?

Amide.

What is the role of starch in the human body?

Complex carbohydrate; energy source.

Why can't a person with Type A blood donate to a person with Type B blood?

Type B blood has A antibodies that react against A antigens.

What is the primary composition of cell membranes?

A bilayer of phospholipids.

What is the difference between 'good' and 'bad' cholesterol?

HDL (good) removes cholesterol; LDL (bad) can clog arteries.

What are three functions of proteins in the body?

Enzymes, structural components, and transport substances.

What are the two main sources of energy from biomolecules?

Glucose (carbohydrate) and fatty acids (lipid).