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NECO Chemistry Past Questions & Answers - Page 22

106.

What mass of copper is deposited when 6.5g of granulated zinc reacts with excess copper(II) tetraoxosulphate(VI) solution?

The equation for the reaction is: Zn(s) + $CuSO_4(aq)→ ZnSO_4(aq)+ Cu(s)$ [CU= 64; Zn=65]

A.

3.2 g

B.

3.25 g

C.

6.4 g

D.

6.5 g

E.

64.0 g

View answer & explanation

Correct answer is C

No explanation has been provided for this answer.

107.

Which element is the most electronegative?

A.

calcium

B.

fluorine

C.

iodine

D.

oxygen

E.

sodium

View answer & explanation

Correct answer is B

No explanation has been provided for this answer.

108.

What change will occur to the equilibrium mixture
$2CrO^{2-}_4(aq) + 2H^+(aq) ⇔ Cr_2O^{2-}_7(aq) + H_2O(l)$ when excess sodium hydrogen solution is added?

A.

A yellow precipitate of Cr(OH)3 is formed

B.

An orange precipitate of Cr(OH)3 is formed

C.

The colour changes from orange to yellow

D.

The colour changes from yellow to orange

E.

There is no visible reaction.

View answer & explanation

Correct answer is C

No explanation has been provided for this answer.

109.

What is the IUPAC name of CH₃CCI=C(CH₃)2?

A.

2-chloro -3 methylbut -2yne

B.

2 -chloro -3 methylbut -2ene

C.

2 -chloro -3 methylbutene

D.

3- methyl -2-chlorobut -2-ene

E.

3- methyl -2. chlorobut -2 yne

View answer & explanation

Correct answer is B

No explanation has been provided for this answer.

110.

Which formula is used to indicate the degree of acidity of an acid?

A.

$[H^+] = ^{\text{mass of acid relative}} molecular mass of acid$

B.

F = number of H+ = ions x molar mass of the acid

C.

Kw = [H+][OH-]

D.

pH = - log₁₀[H+]

E.

pKa = -log₁₀Ka

View answer & explanation

Correct answer is D

No explanation has been provided for this answer.

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