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Flashcards in Practice Midterm Exam Deck (50)
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1
Q

Which of the following describes a scientific law?

A

A scientific law is a concise statement that summarizes a fundamental relationship of nature.

2
Q

Which of the following statements is not a part of Dalton’s atomic theory.

A

The number of protons determines the identity of an atom

3
Q

Which of the following elements of the scientific method is a concise summary of repeated scientific observations?

A

A scientific law.

4
Q

An intensive property such as density is only relevant to pure substances and homogeneous mixtures, and not to heterogeneous mixtures.

A

false

5
Q

“Melting point” is not a(n) _____________________.

A

qualitative property of a substance

6
Q

Which of the following particles have roughly the same mass?

A

a proton and a neutron

7
Q

Lithium combines with fluorine in a 1:1 ratio. Which of the following pairs of elements also combines in a 1:1 ratio?

A

potassium (K) and bromine (Br)

8
Q

What is the coefficient for water in the properly balanced equation for the combustion of butane and oxygen gas to form carbon dioxide gas and water according to the equation:

C4H10 + O2 → CO2 + H2O

A

10

9
Q

What is the mass of the oxygen in 2.0 moles of silver nitrate (AgNO3)?

A

96 grams

10
Q

A reaction has an expected yield of 30.5 grams. What is the percent yield if performing the reaction produced 29.6 grams of product?

A

97.0 percent

11
Q

The following reaction is of which type?

2KClO3(s) -> 2KCl(s) + 3O2

A

oxidation-reduction reaction

12
Q

In an oxidation-reduction reaction, it required 25.6 ml of a 0.65 M potassium permanganate solution to reach the equivalence point with 15.0 mL of an iron(II) sulfate solution. What is the molar concentration of the iron(II) sulfate solution? The net ionic equation for the reaction is:
MnO4-(aq) + 5Fe2+(aq) + 8H+(aq) -> Mn2+(aq) + 5Fe3+(aq) + 4H2O(l)

A

5.6 M

13
Q

A balloon containing 4.28 L of an unknown gas at 1.00 atm and 298 K has a mass of 16.90 g. The empty balloon has a mass of 2.24 g. What is the molar mass of the gas in the balloon?

A

83.8 g/mol

14
Q

The larger the volume of the individual molecules of a gas, the more that gas behaves like an ideal gas.

A

false

15
Q

Which of the following correctly represents an exothermic reaction?

A

ΔH < 0

16
Q

What is the primary difference between coffee-cup calorimetry and bomb calorimetry?

A

Coffee-cup calorimetry is carried out at constant pressure and bomb calorimetry is carried out at constant volume.

17
Q

In the visible absorption spectrum of a gas sample, certain discrete frequencies are missing. What do these missing frequencies represent?

A

Frequencies which cause the electrons of the gas to move to higher energy levels

18
Q

Both the d orbitals and the f orbitals have exactly three angular nodes.

A

false

19
Q

The principal quantum number is not a good indicator of orbital energy level because:

A

of electron shielding

20
Q

Alkali metals are

A

strong reducing agents

21
Q

Which one of the following compounds would you expect to most be ionic?

A

Na2O

22
Q

Which of the following is the correct Lewis dot structure of nitric acid, HNO3?

A

-

23
Q

The following two structures represent resonance structures of one another.

A

false

24
Q

Bond orders which ________ integers indicate molecules with resonance structures.

A

are not

25
Q

The Lewis Dot structure for water can be drawn in the following manner.

What is the steric number value and predicted geometric shape of water based on the SN value?

A

4; tetrahedral

26
Q

Based on MO theory, which of the following has the highest O–O bond order?

A

O2+

27
Q

What are the oxidation states (oxidation numbers) for carbon and oxygen, respectively, in carbonate ion, CO32−?

A

+4, −2

28
Q

Which of the following correctly shows what happens in the two half-reaction steps (oxidation and reduction) in a redox reaction?

A

-

29
Q

Roughly speaking, what is the highest temperature at which a ceramic has been observed to act as a superconductor?

A

77 K

30
Q

A _____ is a gas dispersed in a liquid

A

foam

31
Q

23.10 grams of aluminum metal are dissolved in a solution that contains 1.89 mol of hydrochloric acid to yield aluminum chloride (AlCl3 ) and hydrogen gas according to the following balanced chemical equation. What is the limiting reactant?

2Al(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2(g)
A

HCl

32
Q

A sample of helium gas, initially at standard temperature and pressure, is compressed to a smaller volume at constant temperature. What happens to the frequency of collisions between gas molecules and the walls of the container?

A

They increase

33
Q

What is the energy of an electron in the 2s orbital of a hydrogen atom?

A

−5.45 × 10^−19 J

34
Q

The Lewis dot structure for oxalic acid is shown in the drawing. Which statement about the bond angles for oxalic acid is not true?

A

The H-O-C bond angle is 120°

35
Q

As you move from the left to the right across the periodic table, which of the following is the trend?

A

Increasing ionization energy

36
Q

A sample of gas is at an initial volume of 2.7 L and a temperature of 45°C. If the gas volume increases to 4.2 L, what will its temperature be? You can assume that the pressure remains constant.

A

490 K

37
Q

Two balloons are inflated by a person blowing air into them. Balloon A contains 0.10 mol of air in a volume of 2.44 L. Balloon B contains 0.23 mol of air with a volume of 5.60 L. Assume that air contains 80% nitrogen and 20% oxygen. Is the following statement true or false? The density of air in balloon A is equal to the density of air in balloon B.

A

true

38
Q

It takes 34.8 mL of a 0.0482 M solution of KMnO4 to titrate 20.4 mL of a solution of Na2C2O4 (sodium oxalate) in the presence of excess acid. What is the concentration of the Na2C2O4 solution? (The net ionic equation of the redox reaction is shown below.)

2 MnO4− + 5 C2O42− + 16 H + → 2 Mn2+ + 10 CO2 + 8 H2O

A

0.205 M

39
Q

If you have 5.0 mol Mg3N2, and 6.0 mol H2O, how many moles of Mg(OH)2 would be produced?

Mg3N2(s) + H2O(g) -> Mg(OH)2(s) + NH3(g)

This equation might need balancing.

A

3.0 mol Mg(OH)2

40
Q

You mix 3.4 g of potassium chromate K2CrO4 (194.19 g / mol) with water. If the resulting solution has a volume of 150 mL, what is its molar concentration?

A

0.12 M

41
Q

Which of the following names is incorrect?

A

K2SO3 potassium sulfate

42
Q

Looking at this entry from the periodic table, which of the arrows points to the atomic number?

A

1

43
Q

There are seven basic SI units that define length, mass, time, temperature, chemical amount, electric current, and luminous intensity. There are also many derived units for measurements, such as force, pressure, density, etc. They are essentially combinations of either SI units or non-SI units (e.g. atmospheres, a unit of pressure). Which of the following choices is not one of the seven basic SI units?

A

liter

44
Q

Which of the following sets of measurements of a dose of cough medicine, all in mL, can be described as precise but not accurate if the true value is 15.4 mL?

A

28.3, 28.2, 28.4

45
Q

How many grams of oxygen are present in 15 grams of sodium bicarbonate (NaHCO3 )?

A

8.6 grams

46
Q

In the reaction shown, how many grams of hydrogen gas are produced when 23.10 g aluminum are reacted with 68.8 g HCl?

2Al + 6HCl → 2AlCl3 + 3H2

A

1.90 g

47
Q

What is the work done when a gas expands from 1.00 L to 3.00 L against a constant external pressure of 1.00 atm?

A

−203 J

48
Q

What is true of the enthalpy changes for the following reactions?

Reaction 1: CH4(g) -> C(g) + 4H(g)
Reaction 2: 3C(g) + 12H(g) -> 3CH4(g)

A

The enthalpy change of Reaction 2 is 3 times the magnitude and opposite in sign of the enthalpy change of Reaction 1

49
Q

Which of the following has the highest number of Calories?

A

7.2 g of fat

50
Q

A bulb with a tungsten filament is used as the light source in an absorption experiment. The spectrum that results includes all wavelengths except those corresponding to blue. What is most likely to occur if the experiment is repeated with the same sample, but with a tube of hydrogen gas as the light source rather than the tungsten-filament bulb?

A

The new spectrum will consist of a few separate lines, none of which are blue

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