Flores CHEM 1411 Final F18

Use the following equations to answer the question

(i) H₂O _(g) → H₂O _(l)

(ii) H₂O _(l) → H_{2 (g)} + O_{2 (g)}

(iii) H₂O_{2 (aq)} → H₂O _(l) + O_{2 (g)}

Which of the above equations represent a chemical change?

• i & ii

• ii & iii

• i only

• all

A cube of an unknown metal measures 0.530 cm on one side. The mass of the cube is 1.34 g. Which of the following is most likely the unknown metal?

• zirconium

• rhodium

• vanadium

• copper

In the symbol below ¹³₆X , X = ________.

• nitrogen

• carbon

• aluminum

• potassium

The element X has three naturally occuring isotopes shown in the table above. The average atomic mass of the element is ________ amu.

• 54.32

• 55.74

• 56.11

• 57.23

Which pair of elements would you expect to exhibit the greatest similarity in their physical and chemical properties?

• O, S

• C, N

• K, Ca

• H, He

Which of the following species contains 18 electrons?

• ³¹P

• ³⁴S^2-

• ³⁶Cl

• ⁸⁰Br^1-

The formula for a salt is XBr. The element X is best characterized as ________.

• an alkali metal

• an alkali earth metal

• a halogen

• a noble gas

Which formula/name pair is incorrect?

• Mn(NO₂)₂ : manganese (II) nitrite

• Ca(NO₃)₂ : calcium nitrate

• Mg₃N₂ : magnesium nitrite

• FeSO₄ : iron (II) sulfate

Which pair of atoms constitutes a pair of isotopes of the same element?

• ²⁸₁₃X : ²⁹₁₄X

• ⁵⁹₂₆X : ⁵⁸₂₆X

• ¹⁰₂X : ¹³₃X

• ¹⁰⁷₄₃X : ¹⁰⁹₄₄X

What is the percent of oxygen in perchloric acid?

• 63.7%

• 57.6 %

• 15.9 %

• 25.3 %