Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

492.

By what amount must the temperature of 200cm\(^3\) of Nitrogen at 27°C be increased to double the pressure if the final volume is 150cm\(^3\) (Assume ideality)

A.

150°C

B.

177°C

C.

75°C

D.

120°C

Correct answer is A

Parameters given:

V\(_1\) = 200 cm\(^3\); T\(_1\) = 27 + 273 = 300K.

V\(_2\) = 150 cm\(^3\); T\(_2\) = ?

P\(_2\) = 2P\(_1\).

Using the Ideal Gas Equation:

\(\frac{P_1 V_1}{T_1} = \frac{P_2 V_2}{T_2}\)

\(\frac{P_1 \times 200}{300} = \frac{2P_1 \times 150}{T_2}\)

\(\frac{2}{3} = \frac{300}{T_2}\)

T\(_2\) = 450K.

= 450K - 273K

= 177°C

177 - 27 = 150

That is the amount by which T1 must be increased.

494.

Which of the following statements does not show Rutherford's account of Nuclear Theory? An atom contains a region

A.

which contains protons and neutrons

B.

which is positively charged

C.

which is massive and can cause deflection of a few projectiles

D.

which is very large and in which close to 98% of projectiles pass undeflected

Correct answer is C

Rutherford's account of Nuclear theory does not include the fact that atoms contain a massive region and cause deflection of from projectiles.

495.

SO\(_3\) is not directly dissolved in water in the industrial preparation of H\(_2\)SO\(_4\) by the contact process because

A.

SO\(_3\) is an acidic gas

B.

Acid is usually added to water and not water to acid

C.

The reaction between SO\(_3\) and water is violently exothermic

D.

SO\(_3\) does not dissolve readily in water

Correct answer is C

No explanation has been provided for this answer.