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This exam was created by a large language model. Please use it with caution, as inaccuracies may be present. Always verify critical information.

Which subatomic particle has a negative charge and is found outside the nucleus?

Select one option

Proton

Neutron

Electron

Nucleon

An atom has 15 protons, 16 neutrons, and 15 electrons. What is its mass number?

Select one option

Isotopes of an element have the same number of:

Select one option

Protons and neutrons

Electrons and neutrons

Protons but different neutrons

Neutrons but different protons

The Bohr model of the atom suggests that electrons orbit the nucleus in specific, fixed energy levels. What happens when an electron moves from a lower energy level to a higher energy level?

Select one option

It emits light.

It absorbs energy.

It becomes an ion.

It gains a neutron.

Which of the following statements about the nucleus of an atom is true?

Select one option

It contains only protons.

It contains protons and electrons.

It is negatively charged.

It contains protons and neutrons and is positively charged.

Elements in the same group (column) of the periodic table have similar chemical properties because they have the same number of:

Select one option

Protons

Neutrons

Valence electrons

Total electrons

Which trend correctly describes atomic radius across a period (from left to right) on the periodic table?

Select one option

Increases

Decreases

Remains constant

First increases then decreases

Which element is a noble gas?

Select one option

Oxygen

Chlorine

Neon

Sodium

Which of the following elements is most likely to form a $+2$ ion?

Select one option

Potassium (K)

Calcium (Ca)

Aluminum (Al)

Chlorine (Cl)

10.

Which element has the highest electronegativity?

Select one option

Fluorine (F)

Oxygen (O)

Nitrogen (N)

Carbon (C)

11.

What type of bond is formed when electrons are transferred between atoms, typically a metal and a nonmetal?

Select one option

Covalent bond

Ionic bond

Metallic bond

Hydrogen bond

12.

Which of the following compounds contains a polar covalent bond?

Select one option

$CH_{4}$

$O_{2}$

$HCl$

$NaI$

13.

The Lewis dot structure for a nitrogen atom (N) would show how many valence electrons?

Select one option

14.

What is the correct chemical formula for aluminum oxide?

Select one option

$AlO$

$Al_{2}O_{3}$

$Al_{3}O_{2}$

$AlO_{2}$

15.

Which statement best describes a metallic bond?

Select one option

Sharing of electrons between two nonmetal atoms.

Transfer of electrons from a metal to a nonmetal.

Attraction between positive metal ions and a 'sea' of delocalized electrons.

Weak attraction between nonpolar molecules.

16.

In the reaction $2H_{2} + O_{2} \longrightarrow 2H_{2}O$ , the reactants are:

Select one option

$H_{2}$ and $H_{2}O$

$O_{2}$ and $H_{2}O$

$H_{2}$ and $O_{2}$

Only $H_{2}O$

17.

Which of the following is a balanced chemical equation?

Select one option

$CH_{4} + O_{2} \longrightarrow CO_{2} + H_{2}O$

$CH_{4} + 2O_{2} \longrightarrow CO_{2} + 2H_{2}O$

$C_{2}H_{6} + O_{2} \longrightarrow CO_{2} + H_{2}O$

$N_{2} + H_{2} \longrightarrow NH_{3}$

18.

What type of reaction is $AB + CD \longrightarrow AD + CB$ ?

Select one option

Synthesis

Decomposition

Single Displacement

Double Displacement

19.

A reaction that absorbs energy from its surroundings is called:

Select one option

Exothermic

Endothermic

Combustion

Decomposition

20.

Avogadro's number is equal to:

Select one option

$1.0 \times 10^{23}$ atoms/mole

$6.02 \times 10^{23}$ g/mole

$6.02 \times 10^{23}$ particles/mole

$1.0 \times 10^{-23}$ particles/mole

21.

The molar mass of $H_{2}O$ is approximately:

Select one option

1 g/mol

2 g/mol

18 g/mol

16 g/mol

22.

In a chemical reaction, the limiting reactant is the one that:

Select one option

Is completely consumed and determines the amount of product formed.

Is present in excess and does not affect the product yield.

Reacts slowest and limits the reaction rate.

Is the most expensive reactant.

23.

Propane ( $C_{3}H_{8}$ ) burns in oxygen to produce carbon dioxide and water. If 5.0 moles of propane are completely combusted, what mass of carbon dioxide is produced? Assume excess oxygen. Show all your work and include units. (Molar mass of $CO_{2}$ is $44.01 \text{ g/mol}$ )

24.

Consider the reaction: $2Al(s) + 3Cl_{2}(g) \longrightarrow 2AlCl_{3}(s)$ . If 54.0 g of Aluminum ( $Al$ ) reacts with 71.0 g of Chlorine ( $Cl_{2}$ ), determine the limiting reactant and the theoretical yield of Aluminum Chloride ( $AlCl_{3}$ ) in grams. Show all your work and include units. (Molar mass: $Al = 26.98 \text{ g/mol}$ , $Cl_{2} = 70.90 \text{ g/mol}$ , $AlCl_{3} = 133.34 \text{ g/mol}$ )

25.

A student performs a reaction where the theoretical yield of a product is 15.5 grams. If the student actually obtains 12.0 grams of the product, what is the percent yield of the reaction? Show all your work and include units.

26.

A solution is prepared by dissolving 25.0 grams of sodium hydroxide ( $NaOH$ ) in enough water to make a total volume of 500.0 mL. Calculate the molarity of the $NaOH$ solution. Show all your work and include units. (Molar mass of $NaOH = 40.00 \text{ g/mol}$ )

27.

Compare and contrast ionic and covalent bonds in terms of how they are formed, the types of elements involved, and the general properties of the compounds they form. Provide at least two distinct differences for each aspect.

28.

Explain the concept of electronegativity and how it influences the type of bond (polar covalent, nonpolar covalent, or ionic) formed between two atoms. Give an example for each bond type.

29.

Describe the three main types of radioactive decay (alpha, beta, and gamma) in terms of the particles or energy emitted and their penetrating power. For each type, state a common use or associated hazard.

30.

Balance the following chemical equation and identify the type of reaction: $C_{4}H_{10}(g) + O_{2}(g) \longrightarrow CO_{2}(g) + H_{2}O(g)$

Lab Scenario

Experiment: Synthesis of Copper(II) Carbonate

A student performed an experiment to synthesize Copper(II) Carbonate ( $CuCO_{3}$ ) by reacting Copper(II) Sulfate ( $CuSO_{4}$ ) solution with Sodium Carbonate ( $Na_{2}CO_{3}$ ) solution according to the balanced equation:

$CuSO_{4}(aq) + Na_{2}CO_{3}(aq) \longrightarrow CuCO_{3}(s) + Na_{2}SO_{4}(aq)$

The student followed the procedure:

A solution containing 10.0 g of $CuSO_{4}$ was prepared.
A solution containing 8.0 g of $Na_{2}CO_{3}$ was prepared.
The two solutions were mixed, and a green precipitate of $CuCO_{3}$ formed.
The precipitate was filtered, washed with distilled water, and dried in an oven.
The mass of the dried $CuCO_{3}$ precipitate was measured to be 6.5 grams.

Experimental Data:

Mass of $CuSO_{4}$ used: 10.0 g
Mass of $Na_{2}CO_{3}$ used: 8.0 g
Actual yield of $CuCO_{3}$ : 6.5 g

31.

Using the provided experimental data, calculate the percent yield of Copper(II) Carbonate ( $CuCO_{3}$ ) in this experiment. Show all your work and include units. (Molar mass: $CuSO_{4} = 159.61 \text{ g/mol}$ , $Na_{2}CO_{3} = 105.99 \text{ g/mol}$ , $CuCO_{3} = 123.55 \text{ g/mol}$ )

32.

Identify one possible source of error in this experiment that would lead to a lower calculated percent yield than the actual value. Explain why this error would cause a lower percent yield.