Zn + 2hcl → zncl2 + h2
at conditions of standard temperature and pressure, determine how many liters of hydrogen gas are produced by placing a zinc nail with a mass of 2.2g into an excess of hydrochloric acid.

a) 0.0015 l b) 0.75 l c) 1.33 l d) 6.42 l

0.75L

Explanation:

To get the number of liters of hydrogen gas produced, it is very essential to get the number of moles of hydrogen gas produced.

The number of moles of hydrogen gas produced is obtainable and accessible from

the number of moles of zinc reacted.

Hence, we will get the number of moles of zinc reacted at first. To get the number of moles of zinc reacted, we divide the mass of the zinc by the atomic mass of the zinc metal which is 65.38 amu

The number of moles of the zinc is thus: 2.2/65.38 which equals 0.03365 mole

From the equation of chemical reaction, it can be seen that one mole of zinc metal yielded one mole of hydrogen gas. Hence, it is expected that 0.03365mole of zinc will yield 0.03365mole of hydrogen gas.

Now, we proceed to get the volume of the hydrogen gas produced. We know quite well that at S.T.P a mole of a gas occupies a volume of 22.4L. Hence , 0.03365 mole will occupy a volume of 22.4 * 0.03365 which equals 0.75L

0.75 L of H2 is produced.

Explanation:

From the balanced equation given,we can say that:

1 mole of Zn reacts to give 1 mole of H2.

Since it is carried out at standard temperature and pressure, 1 mole of any gas will occupy 22.4 L.Hence:

1 mole of Zn reacts to give 22.4 L of H2.

Here, mass of Zinc = 2.2 g

Molar mass of Zn = 65 g

Number of moles of Zn =

0.0335 mol of Zn reacts to give = 0.0335×22.4 L of H2

                                                     = 0.75 L

b. accuracy of the data matters alot more than its number of digits, organization or amount of detail. quantitative observation is more accepted than the qualitative observation.