Chemistry Connections Sample Questions

Passport to Science Exploration: Chemistry Connections Sample Questions

—Students may use a periodic table for all questions below—

(1) Zinc(II) acetate, Zn(C2H3O2)2, is a chemical compound that is often used to treat the common cold. What is the chemical formula of an acetate ion?

A. C2H3O2 B. (C2H3O2)2 − C. C2H3O2 2− D. C2H3O2

(2) Cl2O7 is one of several oxides formed by chlorine and oxygen. What is the IUPAC name for Cl2O7?

A. Chlorate B. Chlorine(I) oxide C. Dichlorine septoxide D. Dichlorine heptoxide

(3) Based on the portion of the periodic table shown below, which element has the largest atomic radius?

A. Argon B. Carbon C. Neon D. Silicon

(4) When continually heated in a sealed container, ammonium chloride decomposes into ammonia and hydrogen chloride as shown in the reaction below. What must be true of this reaction?

NH4Cl(s) ⇌ NH3(g) + HCl(g)

A. The reaction can occur without heat if a catalyst is present B. The forward reaction has a lower activation energy than the reverse reaction C. The transition state of the forward reaction is less stable than the transition state of the reverse reaction D. ∆E of the forward reaction equals negative ∆E of the reverse reaction

(5) Hydroxylamine, shown below, is used as a neutralizer in photograph developing solutions. What is the total number of electrons shared between atoms in one molecule of hydroxylamine?

A. 4 B. 8 C. 10 D. 14

(6) Nitric oxide in the human body helps cells respond to their environment. The formation of nitric oxide, shown below, requires a greater amount of energy to break the N2 and O2 bonds than it releases when the NO bonds are formed. Which statement does not describe the formation of nitric oxide?

N2(g) + O2(g)  2NO(g)

A. A synthesis reaction B. An exothermic reaction C. An oxidation reaction D. A reduction reaction

(7) Based on the pH values in the table below, which list of solutions is ordered from highest hydroxide ion concentration to lowest hydroxide ion concentration?

Solution pH 1 4 2 12 3 9 A. 1, 2, 3 B. 1, 3, 2 C. 2, 3, 1 D. 2, 1, 3

(8) In which compound does strontium have the electron configuration of a noble gas?

A. Sr2 B. SrCl C. Sr2Cl D. SrO

(9) Calcium cyanide is used in mining to isolate precious metals like silver and gold. How many formula units of calcium cyanide can be formed from seven atoms of calcium, ten atoms of carbon, and nine atoms of nitrogen?

A. 3 B. 4 C. 5 D. 7

(10) A double replacement reaction occurs between lithium sulfate and barium chloride. In the balanced chemical equation for this reaction, what are the products?

A. 2LiCl + BaS

B. 2LiCl + Ba(SH)2

C. 2LiCl + BaSO4

D. 2LiClO3 + BaSO4

Answer Key

See how you did! Check out the answers below.

(1) C (2) D (3) D (4) D (5) B (6) B (7) C (8) D (9) B (10) C

Please note: CEF does not endorse or approve the use of any CEF Challenge questions for the purposes of preparing for any level of the Challenge. Challenge competition questions (including the Challenge Qualifier) are for competition purposes ONLY. Students should NOT receive or use questions (from the current year or any previous years) at any point to study. Use of Challenge competition questions for study purposes is grounds for disqualification.