Q: Which of the following is the correct molecular formula for glucose?

$$\text{C}_6\text{H}_{12}\text{O}_6$$

Question 1

Which of the following statements best describes the difference between precision and accuracy in a laboratory measurement?

Accepted Answer

Precision refers to how close repeated measurements are to each other, while accuracy refers to how close a measured value is to the true value.

Question 2

A sample of copper contains two isotopes: $$^{63}	ext{Cu} (69.17$$% abundance, mass = 62.93 amu) and $$^{65}	ext{Cu} (30.83$$% abundance, mass = 64.93 amu). What is the atomic weight of copper?

Accepted Answer

$$63.55\ 	ext{amu}$$

Question 3

Which of the following elements is a diatomic molecule in its natural state?

Accepted Answer

Nitrogen ($$	ext{N}_2)$$

Question 4

A student measures the mass of a hydrate sample before and after heating. The initial mass is $$5.00\ 	ext{g}$$, and the mass after heating is $$3.20\ 	ext{g}. $$What is the mass percent of water lost from the hydrate?

Accepted Answer

$$36.0\%$$

Question 5

Which of the following is the correct empirical formula for a compound containing 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass?

Accepted Answer

$$	ext{CH}_3	ext{O}$$

Question 6

Which of the following is NOT a greenhouse gas contributing to climate change?

Accepted Answer

$$	ext{N}_2$$

Question 7

A chemical reaction produces $$2.50\ 	ext{g} of $$product, but the theoretical yield is $$3.00\ 	ext{g}. $$What is the percent yield?

Accepted Answer

$$83.3\%$$

Question 8

Which of the following best describes the purpose of distillation in separating mixtures?

Accepted Answer

To separate components based on their boiling points.

Question 9

What is the molar mass of magnesium sulfate heptahydrate ($$	ext{MgSO}_4\cdot7	ext{H}_2	ext{O}$$)?

Accepted Answer

$$174.37\ 	ext{g/mol}$$

Question 10

Which of the following is a correct statement about ions?

Accepted Answer

Cations are formed when atoms lose electrons.

Question 11

A sample of gas has a density of $$1.25\ 	ext{g/L} at$$ $$25^\circ	ext{C}$$ and $$1.00\ 	ext{atm}. $$What is the mass of $$2.00\ 	ext{L} of $$this gas?

Accepted Answer

$$2.50\ 	ext{g}$$

Question 12

Which of the following elements is a transition metal?

Accepted Answer

Iron ($$	ext{Fe})$$

Question 13

Convert $$25^\circ	ext{C} to $$Kelvin.

Accepted Answer

$$298\ 	ext{K}$$

Question 14

Which of the following is the correct formula for sulfuric acid?

Accepted Answer

$$	ext{H}_2	ext{SO}_4$$

Question 15

Which of the following is a physical property?

Accepted Answer

Boiling point of water

Question 16

A reaction between $$	ext{Na}_2	ext{SO}_4$$ and $$	ext{BaCl}_2$$ produces a precipitate. What is the formula of the precipitate?

Accepted Answer

$$	ext{BaSO}_4$$

Question 17

Which of the following is the correct molecular formula for glucose?

Accepted Answer

$$	ext{C}_6	ext{H}_{12}	ext{O}_6$$

Question 18

According to Dalton’s atomic theory, which statement is correct?

Accepted Answer

Atoms are indivisible in chemical reactions.

Question 19

Which of the following is the general formula for an alkene?

Accepted Answer

$$	ext{C}_n	ext{H}_{2n}$$

Question 20

Which of the following is a main-group element?

Accepted Answer

Sodium ($$	ext{Na})$$

Chem 1A Exam 1 Study Guide: Fundamental Concepts and Calculations

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