Chemistry SOL 2008 (Complete)

A student performed a series of titrations to find the concentration of an unknown acid. The results of the titrations are shown in the data table. What is the mean of this set of data?

• 0.971 M

• 0.976 M

• 0.984 M

• 1.00 M

Answer explanation

The mean of the data set is calculated by adding all values and dividing by the number of values. (0.971 + 0.976 + 0.984 + 1.00) / 4 = 0.984 M, which is the correct choice.

Iodine-131 is a radioactive isotope with a half-life of 8 days. How many grams of a 64 g sample of iodine-131 will remain at the end of 24 days?

• 56 g

• 48 g

• 32 g

• 8 g

Answer explanation

After 24 days, 3 half-lives have passed (8 days x 3 = 24 days). Each half-life halves the amount, so 64 g / 2^3 = 64 g / 8 = 8 g.

Which of the following is the correct name for the compound MnF₃?

• Manganese fluoride(III)

• Manganese(III) fluoride

• Manganese(I) fluoride(III)

• Manganese(III) fluoride(III)

Answer explanation

The correct name for the compound MnF₃ is Manganese(III) fluoride, making the choice 'Manganese(III) fluoride' the correct answer.

The name of the salt formed by the neutralization of hydrochloric acid and sodium hydroxide is —

• sodium chloride

• sodium chlorate

• sodium chlorite

• sodium hypochlorite

Answer explanation

The correct salt formed by the neutralization of hydrochloric acid and sodium hydroxide is sodium chloride.

Tags

NGSS.5-PS1-4

If the quantity of heat lost or gained is (ΔH) = mass × change in T × specific heat, what is the amount of heat required to raise 200.0 g of water from 22.00°C to 100.0°C? Specific heat of water is 4.180 J/g·°C.

• 652.1 joules

• 6,521 joules

• 65,210 joules

• 652,100 joules

Answer explanation

The amount of heat required is calculated using the formula: mass × change in T × specific heat. Plugging in the values: 200.0 g × (100.0°C - 22.00°C) × 4.180 J/g·°C = 65,210 joules.

Tags

NGSS.HS-PS3-4

The coefficients necessary to balance the equation correctly are —

• a = 2, b = 1, c = 1, d = 2

• a = 1, b = 2, c = 1, d = 2

• a = 1, b = 1, c = 1, d = 1

• a = 2, b = 2, c = 1, d = 1

Answer explanation

The correct coefficients to balance the equation are a = 1, b = 2, c = 1, d = 2.

Tags

NGSS.HS-PS1-7

A balloon is filled with 3.8 L of helium gas at STP. Approximately how many moles of helium are contained in the balloon?

• 0.17 mol

• 0.26 mol

• 72 mol

• 85 mol

Answer explanation

At STP, 1 mole of any gas occupies 22.4 L. Therefore, 3.8 L of helium gas contains 3.8/22.4 = 0.17 mol of helium. Hence, the correct answer is 0.17 mol.

Which of these elements has the smallest atomic radius?

• Beryllium (Be)

• Oxygen (O)

• Sodium (Na)

• Sulfur (S)

Answer explanation

Oxygen (O) has the smallest atomic radius among the given elements due to its high effective nuclear charge pulling the electrons closer to the nucleus.

Tags

NGSS.HS-PS1-1

NGSS.HS-PS1-2

If 250.0 mL of a 0.96 M solution of acetic acid (C₂H₄O₂) are diluted to 800.0 mL, what will be the approximate molarity of the final solution?

• 0.19 M

• 0.24 M

• 0.30 M

• 0.77 M

Answer explanation

Dilution formula: M1V1 = M2V2. Solving for M2, we get M2 = (M1V1)/V2 = (0.96*250)/(800) = 0.30 M.

An atom contains 70 protons, 70 electrons, and 99 neutrons. What is the mass number?

• 239

• 169

• 140

• 70

Answer explanation

The mass number is the sum of protons and neutrons in an atom. Therefore, the mass number for this atom is 70 (protons) + 99 (neutrons) = 169.