Test 1 Chem 1 practice

A stock solution of HNO3 has a molarity of 14.9 M. If 25.0 mL of the stock solution is diluted to a final volume of 0.500 L, what is the molarity of the final diluted solution? (1L = 1000 mL)

0.745 M

Determine the number of protons, neutrons, and electrons in Se2− if its mass number is 75.

34 protons, 41 neutrons, 36 electrons

Potassium (K) has an atomic mass of 39.10 amu and only two naturally-occurring isotopes. The K-41 isotope (40.96 amu) has a natural abundance of 6.730%. What is the mass (in amu) of the other isotope?

38.97

How many atoms are present in 2.00 moles of cobalt?

1.2 x 10^24

How many neutrons are there in S-31?

15

How many moles of hydrogen atoms are in 2 moles of C5H8 molecules?

16

A sample of aluminum block contains 4.55 1023 Al atoms. What is the mass (in grams) of the aluminum block?

20

What is the molar mass of strontium nitrate?

211.64 g/mol

Determine the volume (in mL) of a 9.6 M HCl solution required to prepare a 0.5 M solution with a final volume of 500 mL.

26

How many moles of NaOH are present in a solution containing 300 mL of 10.0 M NaOH?

3

How many of the following substances are empirical formulas? C3H8 C6H12O6 H2O2 CH C6H14N2O

3

Calculate the mass (in grams) of solute in 250.0 mL of a 6.00 M aqueous solution of NaOH.

60

What is the mass percent of iron in magnetite (Fe3O4)? (Molar mass of Fe3O4 is 231.55 g/mol)

72%

What is the mass percent of aluminum in Al(ClO3)3?

9.73%

How many N atoms are in 76.3 g of N2O4? The molar mass of N2O4 is 92.02 g/mol.

9.99 × 1023 N atoms

Vinegar is a dilute solution of acetic acid. The molar mass of acetic acid is 60.0 g/mol and it has an empirical formula of CH2O. What is the molecular formula of acetic acid? A) C2H4O2 B) CH2O C) C2H4O D) CH4O E) C2HO2

A

Which one of the following compounds contains ionic bonds? A) CaO B) P2S3 C) NI3 D) HF E) NO2

A

Which of the following represents the INCORRECT element name-symbol combination? A) lead, Pb B) arsenic, Ar C) boron, B D) magnesium, Mg E) chromium, Cr

B

Which one of the following elements will have similar chemical properties as chlorine? A) helium B) bromine C) iron D) calcium E) sulfur

B

What is the empirical formula for a compound based on the following elemental mass percent composition: C 49.48%, H 5.19%, N 28.85%, O 16.48%? A) CHNO B) CH5N2O C) C4H5N2O D) C4H3NO2 E) C12H4N7O4

C

Which of the following is the correct name for the compound Mn2O3? A) dimanganese trioxide B) manganate ion C) manganese(III) oxide D) manganese(II) oxide E) manganese oxide

C

Which of the following statements is TRUE? A) Strontium is in group 3A and is a metal B) Sodium is in group 1A group and is a non-metal C) Silicon is in group 4A and is a metalloid D) Helium is in group 7A and is a non-metal E) Hydrogen is in group 1A and is a transition metal

C

A compound has the empirical formula C3H2N and a molar mass of 312.29 g/mol. What is the molecular formula of the compound?

C18H12N6

An atom has 28 neutrons and a mass of 52 amu. What element is the atom?

Cr

An ionic bond results from: A) the sharing of a pair of electrons B) the attraction of a proton for an electron C) the mutual association of two electrically neutral atoms D) the mutual attraction of a cation and an anion E) the sharing of a single valence electron

D

What ions does Li2CO3 dissociate into in water? A) Li2CO3 only B) 2 Li+, C4+ and O2− C) Li2+, C4+ and O2− D) 2 Li+ and CO32− E) Li2+ and CO32−

D

What is the stoichiometric coefficient for O2(g) when the following chemical equation is balanced using the lowest, whole-number coefficients? ___ C3H6(g) + ___ O2(g) → ___ CO2(g) + ___ H2O(g) A) 2 B) 3 C) 6 D) 9 E) 18

D

Which of the following chemical formulas represent empirical formulas? I. CF2Cl2 II. C10H22 III. Al2(SO4)3

I and III

Which of the following statements are TRUE? I. Electrons make up most of the mass of an atom. II. Neutrons and protons are found in the nucleus of an atom. III. Protons and neutrons have charges that are opposite in sign but equal in magnitude.

II

Which of the following statements about isotopes is/are TRUE? (I) Isotopes of the same element differ only in the number of electrons they contain. (II) Isotopes of the same element have the same mass. (III) Isotopes of the same element have the same number of protons but a different number of neutrons.

III

The positive charge in an atom is

concentrated in the center of an atom