Q: A patient receives a medication dosed at 0.5 mg/kg. If the patient weighs 154 lb, how many milligrams of medication should they receive? (1 kg = 2.205 lb)

$$0.5 \times \frac{154}{2.205} = 35 mg$$

Q: A compound contains 2.0 moles of carbon atoms. How many atoms of carbon are present? ($$1$$ mole $$= 6.02 \times 10$$^{23}$$ atoms)

$$2.0 \times 6.02 \times 10$$^{23}$$ = 1.204 \times 10$$^{24}$$ atoms

Question 1

Which of the following statements best describes the difference between physical and chemical changes? Choose the most accurate answer.

Accepted Answer

Chemical changes alter the composition of a substance, while physical changes only affect its state or appearance.

Question 2

A patient receives a medication dosed at 0.5 mg/kg. If the patient weighs 154 lb, how many milligrams of medication should they receive? (1 kg = 2.205 lb)

Accepted Answer

$$0.5 	imes \frac{154}{2.205} = 35 mg$$

Question 3

Which of the following ions is polyatomic and carries a -2 charge?

Accepted Answer

$$\mathrm{CO_3$^{2-}}$$

Question 4

Which statement about isotopes is correct?

Accepted Answer

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

Question 5

A solution has a mass of 250 g and a volume of 200 mL. What is its density in $$\mathrm{g/mL}$$?

Accepted Answer

$$\frac{250}{200} = 1.25$$ $$\mathrm{g/mL}$$

Question 6

Which of the following best describes the process of scientific notation?

Accepted Answer

Expressing numbers as a product of a coefficient between 1 and 10 and a power of 10.

Question 7

Which of the following is the correct electron configuration for a neutral oxygen atom?

Accepted Answer

$$1s^2$$ $$2s^2$$ $$2p^4$$

Question 8

Which of the following conversions is correct for converting 1.5 L to mL?

Accepted Answer

$$1.5 	imes 1000 = 1500 mL$$

Question 9

Which of the following is the correct formula for ammonium sulfate?

Accepted Answer

$$\mathrm{(NH_4$)_2SO_4}$$

Question 10

A radioactive isotope undergoes beta decay. Which particle is emitted and what happens to the atomic number?

Accepted Answer

An electron is emitted; atomic number increases by 1.

Question 11

Which of the following polyatomic ions is correctly matched with its formula and charge?

Accepted Answer

Nitrate: $$\mathrm{NO_3$^-}$$

Question 12

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

Accepted Answer

Magnesium ($$\mathrm{Mg})$$

Question 13

Which of the following is the correct balanced chemical equation for the reaction of sodium hydroxide with hydrochloric acid?

Accepted Answer

$$\mathrm{NaOH + HCl \rightarrow NaCl + H_2O}$$

Question 14

Which of the following statements about valence electrons is correct?

Accepted Answer

Valence electrons determine the chemical reactivity of an element.

Question 15

A compound contains 2.0 moles of carbon atoms. How many atoms of carbon are present? ($$1$$ mole $$= 6.02 	imes 10$$^{23}$$ atoms)

Accepted Answer

$$2.0 	imes 6.02 	imes 10$$^{23}$$ = 1.204 	imes 10$$^{24}$$ atoms

Question 16

Which of the following is the correct name for $$\mathrm{$$FeCl_3$$}$$?

Accepted Answer

Iron(III) chloride

Question 17

Which of the following best describes the term 'isoelectronic'?

Accepted Answer

Atoms or ions with the same number of electrons.

Question 18

Which of the following is the correct formula for the polyatomic ion chlorate?

Accepted Answer

$$\mathrm{$$ClO_3$$^-}$$

Question 19

A radioactive isotope has a half-life of 4 hours. If you start with 80 g, how much remains after 12 hours?

Accepted Answer

$$80 \div 2^3$ = 10 g$$

Question 20

Which of the following is the correct Lewis structure for the carbonate ion ($$\mathrm{CO_3$^{2-}}$$)?

Accepted Answer

Three resonance structures with one double bond and two single bonds distributed among the oxygens, with a $$2^-$$ charge spread over the oxygens.

GOB Chemistry Study Guide: Atomic Structure, Periodic Table, and Chemical Calculations

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