Q: How many oxygen atoms are contained in $$47.6 g of Al$_2(CO$_3$$)$$_3$$? (molar mass Al$$_2(CO$_3$$)$$_3$$ = $$233.99 g/$$mol)

$$1.10 \times 10$$^{24}$$ atoms

Question 1

Which statement best explains why ionic compounds are electrically neutral overall?

Accepted Answer

Because cations and anions always occur together in compounds so that the overall charge is zero.

Question 2

A sample of silver contains two isotopes: Ag-107 (atomic mass = 106.90509 amu, abundance = 51.84%) and Ag-109 (atomic mass = 108.90476 amu, abundance = 48.16%). What is the average atomic mass of silver?

Accepted Answer

$$108.19$$ amu

Question 3

Which of the following is a correct balanced equation for the reaction of aqueous aluminum acetate with aqueous ammonium phosphate to form solid aluminum phosphate and aqueous ammonium acetate?

Accepted Answer

$$Al(C_2H_3O_2)_3(aq) + (NH_4$)_3PO_4(aq) \rightarrow $$AlPO_4$$(s) + 3 NH_4C_2H_3O_2(aq)$$

Question 4

A piece of metal weighs $$45.42 g. $$When the metal is placed in a graduated cylinder containing water, the liquid level rises from $$26.30 mL to$$ $$31.38 mL. $$What is the density of the metal?

Accepted Answer

$$8.94 g/cm$^3$$

Question 5

Which of the following statements about subatomic particles is true?

Accepted Answer

A neutral atom contains the same number of protons and electrons.

Question 6

What is the empirical formula of a hydrocarbon that yields $$2.20 g CO$_2$$ and $$1.08 g H$_2O $$upon combustion? (Molar mass of hydrocarbon is $$72.18 g/$$mol)

Accepted Answer

$$CH_2$$

Question 7

Which of the following pairs are isotopes of the same element?

Accepted Answer

$$^{12}C$$ and $$^{13}C$$

Question 8

Calculate the percent composition of lithium in Li$$_3PO$_4 ($$molar mass Li$$_3PO$_4$$ = $$115.79 g/$$mol).

Accepted Answer

$$17.98\%$$

Question 9

Which of the following is a molecular element?

Accepted Answer

$$N_2$$

Question 10

A student measures the mass of tin to be $$0.5$$ mol. Which of the following has the greatest mass?

Accepted Answer

$$0.5$$ mol tin

Question 11

Which of the following compounds contains both ionic and covalent bonds?

Accepted Answer

$$KNO_3$$

Question 12

What is the molar mass of Ca$$_3(PO$_4$$)$$_2$$?

Accepted Answer

$$310.17 g/$$mol

Question 13

Which of the following statements is true about ductility?

Accepted Answer

Ductility is a term that means 'ability to be drawn into a thin wire'.

Question 14

Which of the following is the highest temperature?

Accepted Answer

$$274\ ^\circ C$$

Question 15

How many oxygen atoms are contained in $$47.6 g of Al$_2(CO$_3$$)$$_3$$? (molar mass Al$$_2(CO$_3$$)$$_3$$ = $$233.99 g/$$mol)

Accepted Answer

$$1.10 	imes 10$$^{24}$$ atoms

Question 16

Which of the following is a heterogeneous mixture that can scatter light as a colloid?

Accepted Answer

Milk

Question 17

Which of the following name-formula pairs are incorrect?

Accepted Answer

C, D, and E only

Question 18

What is the empirical formula for glucose, C$$_6H$_{12}O$_6$$?

Accepted Answer

$$CH_2O$$

Question 19

Which of the following elements will most likely form ionic cations in compounds?

Accepted Answer

Calcium

Question 20

A reaction yields $$5.00 g of $$calcium hydroxide when $$12.0 g of $$calcium metal is reacted with water. Calculate the percent yield for the reaction. (Balanced equation: $$Ca + 2H_2O \rightarrow Ca(OH)_2 + H_2$)

Accepted Answer

$$22.5\%$$

General Chemistry Exam Study Guide: Key Concepts, Equations, and Problem-Solving Strategies

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