Q: Which of the following is the correct formula for calculating the percent composition by mass of an element in a compound?

$\frac{\text{mass of element in 1 mol of compound}}{\text{molar mass of compound}} \times 100\%$

Question 1

Which of the following best describes the primary focus of GOB (General, Organic, and Biological) Chemistry as outlined in the course description?

Accepted Answer

The study of hydrocarbons and their derivatives, with an emphasis on their relevance to biological and health sciences.

Question 2

A student is asked to balance the following chemical equation: $ \mathrm{C_2H_6} + \mathrm{O_2} \rightarrow \mathrm{CO_2} + \mathrm{H_2O} $. What is the correct set of coefficients (in order: $\mathrm{C_2H_6}$, $\mathrm{O_2}$, $\mathrm{CO_2}$, $\mathrm{H_2O}$)?

Accepted Answer

$2, 7, 4, 6$

Question 3

Which of the following statements about ionic and covalent compounds is correct?

Accepted Answer

Ionic compounds are formed by the transfer of electrons from metals to nonmetals.

Question 4

A patient is given a saline solution containing $0.90\%$ NaCl by mass. If the patient receives $500\ \mathrm{mL}$ of this solution (density $= 1.00\ \mathrm{g/mL}$), how many grams of NaCl did the patient receive?

Accepted Answer

$45\ \mathrm{g}$

Question 5

Which of the following is the correct IUPAC name for the compound $\mathrm{CH_3CH_2OH}$?

Accepted Answer

Ethanol

Question 6

A sample contains $3.01 	imes 10^{23}$ molecules of glucose ($\mathrm{C_6H_{12}O_6}$). What is the mass of glucose in the sample? (Molar mass of glucose $= 180\ \mathrm{g/mol}$)

Accepted Answer

$15\ \mathrm{g}$

Question 7

Which of the following best explains why water is considered a polar molecule?

Accepted Answer

The oxygen atom is more electronegative, creating a partial negative charge at one end and a partial positive charge at the other.

Question 8

A chemical reaction has $\Delta H < 0$ and $\Delta S > 0$. Which of the following statements is true about the spontaneity of the reaction at all temperatures?

Accepted Answer

The reaction is spontaneous at all temperatures.

Question 9

Which of the following is the correct electron configuration for a neutral atom of sodium ($\mathrm{Na}$, atomic number 11)?

Accepted Answer

$1s^2 2s^2 2p^6 3s^1$

Question 10

A solution is prepared by dissolving $10.0\ \mathrm{g}$ of NaOH in enough water to make $500.0\ \mathrm{mL}$ of solution. What is the molarity of the solution? (Molar mass of NaOH $= 40.0\ \mathrm{g/mol}$)

Accepted Answer

$0.50\ \mathrm{M}$

Question 11

Which of the following best describes the function of a buffer solution in the human body?

Accepted Answer

It maintains a relatively constant pH by neutralizing added acids or bases.

Question 12

Which of the following is a correct statement about the law of conservation of mass?

Accepted Answer

The total mass of reactants equals the total mass of products in a chemical reaction.

Question 13

A patient is prescribed a medication that requires a dosage of $2.5\ \mathrm{mg/kg}$ body weight. If the patient weighs $70\ \mathrm{kg}$, what is the total dose required?

Accepted Answer

$175\ \mathrm{mg}$

Question 14

Which of the following is the correct formula for calculating the percent composition by mass of an element in a compound?

Accepted Answer

$\frac{	ext{mass of element in 1 mol of compound}}{	ext{molar mass of compound}} 	imes 100\%$

Question 15

Which of the following best explains why noble gases are generally unreactive?

Accepted Answer

They have a full valence shell, making them stable and unlikely to form bonds.

Question 16

A reaction is carried out at constant pressure and releases $150\ \mathrm{kJ}$ of heat. What is the value of $\Delta H$ for this reaction?

Accepted Answer

$-150\ \mathrm{kJ}$

Question 17

Which of the following is the correct balanced equation for the complete neutralization of sulfuric acid ($\mathrm{H_2SO_4}$) with sodium hydroxide ($\mathrm{NaOH}$)?

Accepted Answer

$\mathrm{H_2SO_4} + 2\mathrm{NaOH} \rightarrow \mathrm{Na_2SO_4} + 2\mathrm{H_2O}$

Question 18

Which of the following is a correct statement about isotopes?

Accepted Answer

Isotopes of an element have the same number of protons but different numbers of neutrons.

Question 19

A gas occupies $2.0\ \mathrm{L}$ at $1.0\ \mathrm{atm}$ and $300\ \mathrm{K}$. What will be its volume at $2.0\ \mathrm{atm}$ and $300\ \mathrm{K}$, assuming ideal gas behavior?

Accepted Answer

$1.0\ \mathrm{L}$

Elementary Chemistry (CHEM 1110) Syllabus and Course Overview

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