Answers2025-2026_MDCPS_2003345_Chemistry_1_A-CRCumulative Exam

Cumulative Exam — Cumulative exam Answers

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The table below gives the numbers of protons, electrons, and neutrons in four atoms.AtomNumber of protonsNumber of electronsNumber of neutrons1393952240405033939544404051Based on the information that is given, which atom in the table has the highest mass?

A
1
B
2
C
3
D
4
2
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Consider the chemical reaction in equilibrium. H2 + I2 + heat 2HI What will happen to the chemical equilibrium if the temperature of the system is increased?

Question illustration
A
The direction of the chemical equilibrium will shift to the right, favoring the forward reaction.
B
The chemical equilibrium will not be affected by an increase in temperature.
C
The direction of the chemical equilibrium will shift to the left, favoring the reverse reaction.
D
The chemical equilibrium will be lost permanently with a change of temperature.
3

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4

The periodic table below shows the electronegativity values of some elements.ElectronegativitiesConsider the positions of barium (Ba), sulfur (S), silicon (Si), and calcium (Ca) on the periodic table. The atoms of which element require the least amount of energy to give up an electron when forming chemical bonds?

Question illustration
A
barium
B
sulfur
C
silicon
D
calcium
5

Consider the diagram.Which postulate of the kinetic-molecular theory best describes the event in the diagram?

Question illustration
A
Most of the volume of a gas is empty space.
B
All collisions between particles are perfectly elastic.
C
There is no force of attraction or repulsion between gas particles.
D
The average kinetic energy of particles depends only on temperature.
6

A single atom of an element has 21 neutrons, 20 electrons, and 20 protons. Which element is it?

A
K
B
Zr
C
Ca
D
Sc
7

Consider the unbalanced equation for the oxidation of aluminum._Al + _O2 _Al2O3Which sequence of coefficients should be placed in the blanks to balance this equation?

Question illustration
A
2, 3, 1
B
1, 3, 2
C
4, 3, 2
D
3, 2, 3
8

In an investigation with density, Marcia’s teacher measures the mass and volume of 10 different samples of a substance. The samples are numbered 1 through 10. Then, the teacher makes the graph that is shown below.What is the independent variable in this investigation?

Question illustration
A
mass
B
volume
C
sample number
D
substance density
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10

Which diagram shows electrons violating the Pauli exclusion principle?

A
A box contains an up arrow.
Option A
B
A box contains an up and a down arrow.
Option B
C
A box contains an up and a down arrow.
Option C
D
A box contains an up and a down arrow.
Option D
11

The properties of two elements are listed below.ElementAtomic radius(pm)Ionic radius(pm)First ionization energy(kJ/mol)Electron affinity(kJ/mol)ElectronegativityBr1141951140–3253.0K243152.2418.8–48.40.82Which prediction is supported by the information in the table?

A
K will give up an electron more easily than Br.
B
Both K and Br will have the same pull on electrons.
C
K will have a smaller size in comparison to Br.
D
Both K and Br will produce ions of the same size.
12

In the molecules below, areas that have a partial negative charge are pink and areas that have a partial positive charge are blue. The attractive force between these two molecules has most likely been produced by

Question illustration
A
covalent bonds.
B
dipole-dipole interactions.
C
dipole-induced dipole interactions.
D
London dispersion forces.
13

Which is a feature of a single replacement reaction?

A
Substance XYZ breaks down into X and YZ.
B
Substance G reacts with compound XY to form GY and X.
C
Substance X burns rapidly in the presence of oxygen.
D
Substance QR and GT exchange ions with each other.
14

A teacher wants to perform a classroom demonstration that illustrates both chemical and physical changes. Which would be the best demonstration that she could use?

A
bending a piece of aluminum
B
breaking a matchstick
C
dissolving sugar in water
D
burning a candle
15

Kumar is producing the photoelectric effect by using red light. He wants to increase the energy of emitted electrons. Based on the research of Albert Einstein, what is the best way for him to do this?

A
Increase the intensity of red light.
B
Decrease the intensity of red light.
C
Use a different colored light that has a higher frequency.
D
Use a different colored light that has a lower frequency.
16

When chemists convert ethene (C2H2) to ethanol (CH3CH2OH), they have a mixture of the two gaseous substances. Why do chemists then lower the temperature of the mixture?

A
to collect liquid ethene and leave ethanol as a gas because ethene has stronger dipole-dipole forces
B
to collect liquid ethene and leave ethanol as a gas because ethanol has stronger London dispersion forces
C
to collect liquid ethanol and leave ethene as a gas because ethanol has hydrogen bonds
D
to collect liquid ethanol and leave ethene as a gas because ethene has stronger London dispersion forces
17

Which statement best explains why different gases effuse at different rates?

A
At a given pressure, gas particles with smaller masses move faster.
B
At a given pressure, gas particles with smaller masses move slower.
C
At a given temperature, gas particles with smaller masses move faster.
D
At a given temperature, gas particles with smaller masses move slower.
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Answer not available
19

An electron in a hydrogen atom moves from level 1 to level 4. The electron then drops from level 4 to level 2. Which statement describes the most likely result?

A
The energy absorbed in the first move equals the energy released in the second move.
B
The energy absorbed in the first move is greater than the energy released in the second move.
C
The energy released in the first move equals the energy absorbed in the second move.
D
The energy released in the first move is greater than the energy absorbed in the second move.
20

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