Chemistry 1151L Test 1 (Answers)

Which of the following statements is true about an isotope.

a) Isotopes are the atoms of same element. They have same number of protons, but different number of neutrons.

b) Isotopes are the atoms of same element. They have same number of protons, but different electronic arrangement.

c) Isotopes are the atoms of different elements. They have same number of protons, but different number of electrons.

d) Isotopes are the atoms of same element. They have same number of neutrons, but different number of protons.

a) Isotopes are the atoms of same element. They have same number of protons, but different number of neutrons.

Arrange following elements in an increasing order of atomic radius.

P, Cl, Al

a) Al < P < Cl

b) Cl < Al < P

c) P < Al < Cl

d) Cl < P < Al

d) Cl < P < Al

Round off the answer to the appropriate significant figures:

(4.501 x 0.00320)/34.00

a) 4.24 x 10^-4

b) 4.236 x 10^-4

c) 4.2 x 10^-4

d) 4 x 10^-4

a) 4.24 x 10^-4

Which instrument is used for measuring the specific gravity of a liquid?

a) Graduated Cylinder

b) Thermometer

c) Hydrometer

d) Chemical Balance

c) Hydrometer

Density of a sample of an alloy is 7.20 g/mL. If the volume of the alloy is 22.4 mL. What is the mass of the alloy sample?

a) 3.11 g/mL

b) 161 g

c) 0.321 g

d) 22.4 g

b) 161 g

204.020 g has --- number of significant figures in it?

a) 4

b) 6

c) 3

d) 5

b) 6

Determine the density of a 3D-rectangular object. The mass of the object was 434.4 g. The length, width, and height of the object were 14.5 cm, 12.2 cm, and 0.750 cm, respectively.

(Hint: volume of a 3D-rectangular object = length x width x height)

a) 0.306 g/cm³

b) 3.27 g/cm³

c) 3.14 g/cm³

d) 0.318 g/cm³

b) 3.27 g/cm³

A student submerged a metal object into a graduated cylinder filled with water. The initial and final levels of water in the graduated cylinder were 20.0 mL and 23.0 mL, respectively. The mass of the metal object was 24.3 g. Determine the density of the metal object.

a) 1.0 g/mL

b) 1.22 g/mL

c) 0.12 g/mL

d) 8.1 g/mL

d) 8.1 g/mL

Molecule H₂O has --- electron group and --- molecular geometry, respectively.

a) bent, trigonal pyramidal

b) tetrahedral, bent

c) trigonal planar, tetrahedral

d) bent, linear

b) tetrahedral, bent

Which of the following statements best describes a chemical reaction between powdered calcium carbonate (CaCO₃)  and hydrochloric acid (HCl)?

a) This is an example of double replacement reaction and light is produced in this reaction.

b) This is an example of double replacement reaction and a gas is produced in this reaction.

c) This is an example of combustion reaction and a gas is produced in this reaction.

d) This is an example of single replacement reaction and light is produced in this reaction.

b) This is an example of double replacement reaction and a gas is produced in this reaction.

Mercury has a density of 13.5 g/mL. What volume of this liquid would have a mass of 269 g?

a) 283 mL

b) 0.0502 mL

c) 19.9 mL

d) 3.63 x 10³ mL

c) 19.9 mL

The number of neutrons in an atom can be determined from -----.

a) Atomic mass minus mass number.

b) Mass number minus atomic number.

c) Atomic number minus mass number.

d) Number of protons minus number of electrons.

b) Mass number minus atomic number.

Which statements is true regarding molecule CH₄?

a) This molecule has one lone pair of electrons on the carbon and has a tetrahedral molecular geometry.

b) This molecule has no lone pairs of electrons on the carbon and has a trigonal pyramidal molecular geometry.

c) This molecule has one lone pair of electrons on the carbon and has a trigonal planar molecular geometry.

d) This molecule has no lone pairs of electrons on the carbon and has a tetrahedral molecular geometry.

d) This molecule has no lone pairs of electrons on the carbon and has a tetrahedral molecular geometry.

Locate fluorine (F) and phosphorus (P) on the periodic table. Based on their location what can you conclude about them?

a) Phosphorus is inert and fluorine is less reactive element.

b) Phosphorus atom's atomic radius is larger than that of fluorine atom.

c) Phosphorus atom's atomic radius is smaller than that of fluorine atom.

d) They are equal in the atomic size.

b) Phosphorus atom's atomic radius is larger than that of fluorine atom.

The atomic radius of atoms generally ----- as we go from left to right across the periodic table and ----- as we go from top to bottom in a group of a periodic table, respectively.

a) Increases, Decreases

b) Decreases, Does not change

c) Does not change, Decreases

d) Decreases, Increases

d) Decreases, Increases

The mass of an unknown liquid sample was 72.2 g. The density of the sample was 1.27 g/mL. Determine the volume of the sample.

a) 569 mL

b) 0.0176 mL

c) 91.7 mL

d) 56.9 mL

d) 56.9 mL

The mass of an irregular shaped object was 17.9 g. The object was completely immersed in water and the water level rose from 35.7 mL to 43.8 mL. Determine the density of the object.

a) 2.21 g/mL

b) 22.1 g/mL

c) 0.409 g/mL

d) 1.79 g/mL

a) 2.21 g/mL

Lewis structure of ammonia (NH₃) represents that the molecule has --- bonding and --- nonbonding electron clouds, respectively.

a) 2, 2 

b) 4, 1

c) 3, 1

d) 3, 0

c) 3, 1

Magnesium metal Mg burns in air as it chemically reacts with oxygen from air to form magnesium oxide. Which balanced chemical reaction best describes this change?

a) 2Mg(s) + O₂(g) = 2MgO(s)

b) 2Mg(g) + O₂(g) = 2MgO(g)

c) Mg(s) + O₂(g) = MgO(s)

d) Mg(s) + O₂(g) = MgO₂(s)

a) 2Mg(s) + O₂(g) = 2MgO(s)

Before starting an experiment:

a) Follow your common sense.

b) Read the entire procedure.

c) Skip to the laboratory report and try to figure out what to do.

d) Ask your lab partner how to do the experiment.

b) Read the entire procedure.