Chemistry

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?

8g

What is the correct name for the compound MnF3?

Manganese(III) fluoride

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

sodium chloride

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

Which of these elements has the smallest atomic radius? Beryllium (Be), Oxygen (O), Sodium (Na), Sulfur (S)

Oxygen (O)

If 250.0 mL of a 0.96 M solution of acetic acid (C2H2O2) are diluted to
800.0 mL, what will be the approximate molarity of the final solution?

0.30 M

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

169

Which set of equipment would be most useful to determine the density of
a liquid? balance and periodic table, periodic table and thermometer, balance and graduated cylinder or graduated cylinder and thermometer.

Balance and graduated cylinder

Sodium chloride conducts electricity when dissolved in water. What type of
bond is present in NaCl?

Ionic

After 1911, most scientists accepted the theory that the nucleus of an atom
was very dense and very small and had a positive charge. What led scientists
to accept this theory?

Rutherford did an experiment firing alpha particles at a thin piece of gold foil.

A sodium atom has an electron configuration of If the sodium
atom becomes ionized, its new electron configuration will be the same as
which element? Lithium, Magnesium, Neon or Potassium.

Neon

Which of the following particles has a positive one charge? Alpha, Electron, Proton or Neutron.

Proton

What is the mass of one mole of CO2?

44g

According to the periodic table, Mg will most likely react with elements in
which of these groups? 1, 3, 17 or 18

17

A student is given a container of potassium nitrate crystals. In order to
determine the exact mass of the potassium nitrate using a triple beam
balance, he must know the —

mass of the empty container and the mass of the filled container

C-12 and C-13 are naturally-occurring isotopes of the element carbon.
C-12 occurs 98.89% of the time and C-13 occurs 1.108% of the time. What
calculation should be used to determine the atomic mass of this element?

(12 × 0.9889) + (13 × 0.01108)

The general equation shown in AB + energy A + B is an —

endothermic decomposition

In order to determine the identity of a substance, a student listed the
following properties. Which of the following is a chemical property? Oxidizes in air, Conducts an electric current, Attraction to a magnet, Dissolves in water.

Oxidizes in air

Which of the following is a solid/solid solution? An alloy of gold and copper, A mixture of argon and krypton, A strongly electrolytic acid, A neutralized base.

An alloy of gold and copper

Which of these compounds is most likely to contain an ionic bond? H2, SO2, CH4, CaCl2.

CaCl2

The composition of dry air is approximately 78% nitrogen, 21% oxygen,
and 1% other gases. What is the partial pressure of nitrogen at standard
atmospheric pressure (101.3 kPa)?

79.0 kPa

A gas has a volume of 100.0 mL at a pressure of 600.0 mm Hg. If the
temperature is held constant, what is the volume of the gas at a pressure of
800.0 mm Hg?

75.00 mL

Which element is a noble gas? Fluorine (F), Hydrogen (H), Nitrogen (N), Xenon (Xe).

Xenon (Xe)

To determine if a reaction is exothermic, a student should use a —

temperature probe

What is the name of NH4 OH?

Ammonium hydroxide

A student hypothesizes that the solubility of a particular solute in water is
nearly constant as temperature varies. The student can best test the
hypothesis by doing what?

Measuring the solubility of the solute at five different temperatures

What is the correct name for the compound P4O6?

Tetraphosphorus hexoxide

As heat is added to a substance undergoing a phase change, the temperature
remains constant because the energy is being used to —

overcome intermolecular forces

What is the chemical formula for iron(II) phosphide?

Fe3P2

In a mixture of oxygen and nitrogen gas, 80.0 percent of the total
gas pressure is exerted by the nitrogen. If the total pressure is 2.0 atm, what
pressure does the oxygen exert?

0.40 atm

Atoms of the noble gases are generally inert because —

their outer electron levels are filled 1 What is the volume of the liquid in the graduated cylinder? A 13.00 mL B 13.50 mL C 14.00 mL D 14.50 mL

What is the mass of a mole of Ca(OH)2?

74 grams

Which of the elements has the same Lewis structure as Sulfur? Chlorine, Magnesium, Oxygen, Phosphorus.

Oxygen

A mixture of gases with a pressure of 800.0 mm Hg contains 60% nitrogen
and 40% oxygen by volume. What is the partial pressure of oxygen in this
mixture?

320.0 mm Hg

The formula for magnesium chloride is —

MgCl2

What are the numbers of protons, neutrons, and electrons in an isotope of
titanium with a mass number of 50?

22 p, 28 n, 22 e

Water and ammonia have different molar heats of vaporization. The best
interpretation, at the molecular level, is that water molecules —

have stronger intermolecular attractions

What statement could describe what happens to the molecules of a solid
as the temperature is lowered to absolute zero?

Their motion gradually decreases and eventually stops

What mass of nitrogen is required to react with 16 grams of oxygen?

5.6 g

The correct name for Mg3 (PO4)2 is —

magnesium phosphate

How many protons are in an atom represented by 220/88 Ra?

88

According to the kinetic-molecular theory of gases, molecules of an ideal
gas —

undergo elastic collisions

What is the molar mass of beryllium oxide (BeO)?

25 g/mol

Catalytic converters made of palladium (Pd) reduce automobile pollution by
catalyzing the reaction between unburned hydrocarbons and oxygen. How
does Pd increase the rate of this reaction?

By decreasing the activation energy

A chloride ion has the same number of electrons as a neutral atom of —

argon

Which compound has a covalent bond? CaI2, KBr, NaCl, NO.

NO

What would best describe sublimation?

A solid changing to a gaseous phase

If the difference in electronegativity between atoms of different non-metals is
small, the atoms of the two non-metals will most likely —

form a covalent bond

The role of a catalyst is to affect —

activation energy

What best describes the difference between the formulas for
nitrogen monoxide and nitrogen dioxide?

Nitrogen monoxide has one fewer atom of oxygen

When compared to sulfur-32, sulfur-34 has more —

neutrons

What is the chemical name for the compound P3N5?

Triphosphorus pentanitride

What is the safest practice when heating the contents of a test tube over a
flame?

Pointing the test tube away from people

The boiling point of ethanol is 78.3°C. The boiling point of ethanol on the
Kelvin scale is approximately —

351 K

What does pH measure?

Hydrogen ion concentration

The proper scientific notation for 565,000,000,000 is —

5.65 × 10^11

What are shared in covalent bonds?

Electrons

What is the percent of error in evaluating the molecular mass of a
compound if the experimental value was 105.2 amu and the known value was
107.5 amu?

2.1%

What is the correct formula for aluminum chloride?

AlCl3

The elements that are characterized by
the presence of an incomplete d
sublevel are called —

transition elements