Question

Which one occupies the maximum volume at STP?
(a) 16g of ${{\text{O}}_{2}}$
(b) 36g of $\text{C}{{\text{l}}_{2}}$
(c) 16g of $\text{C}{{\text{H}}_{4}}$
(d) 14g of ${{\text{N}}_{2}}$

Answer 1

Hint: STP refers to Standard Temperature and Pressure defined by IUPAC (International Union of Pure and Applied Chemistry). In these conditions, the volume of 1 mol of a gas is 22.418 liters.

Complete step by step answer:
> STP is commonly used to define standard conditions for temperature and pressure which is important for the measurements and documentation of physical and chemical processes.
> According to the International Union of Pure and Applied Chemistry (IUPAC), the currently accepted values for standard temperature and pressure are 273.15 K (${{0}^{\text{o}}}\text{C}$) and exactly 100kPa (0.986923 atm). The purpose of STP is to provide chemists with a common experimental baseline from which to interpret and compare data.
> As we know that one mole of a gas at STP occupies 22.4 liters of a molecular substance
- 1 mole of ${{\text{O}}_{2}}$ contains 16x2=32g of ${{\text{O}}_{2}}$
32g of ${{\text{O}}_{2}}$=22.4 L
16g of ${{\text{O}}_{2}}$=$\dfrac{22.4}{32}\text{x16=11}\text{.2L}$$\dfrac{22.4}{32}\text{x16=11}\text{.2L}$
- 1 mole of $\text{C}{{\text{l}}_{2}}$ contains 35.45 x 2=70.9g of $\text{C}{{\text{l}}_{2}}$
70.9g of $\text{C}{{\text{l}}_{2}}$=22.4L
36g of $\text{C}{{\text{l}}_{2}}$=$\dfrac{22.4}{70.9}\text{x36}$=11.37L
- 1 mole of $\text{C}{{\text{H}}_{4}}$contains 16g of$\text{C}{{\text{H}}_{4}}$
16g of$\text{C}{{\text{H}}_{4}}$=22.4L
- 1 mole of ${{\text{N}}_{2}}$ contains 28g of ${{\text{N}}_{2}}$
28g of ${{\text{N}}_{2}}$=22.4L
14g of ${{\text{N}}_{2}}$=$\dfrac{22.4}{28}\text{x14=11}\text{.2L}$
Therefore, the answers of above calculations are:
(a) 16g of ${{\text{O}}_{2}}$ =11.2L
(b) 36g of $\text{C}{{\text{l}}_{2}}$ =11.37L
(c) 16g of $\text{C}{{\text{H}}_{4}}$=22.4L
(d) 14g of ${{\text{N}}_{2}}$ =11.2L
Therefore option (c) 16g of $\text{C}{{\text{H}}_{4}}$ is the correct answer.

Note: It should be noted that chemists require STP definitions because the behaviour of a substance varies greatly depending on the temperature and pressure. STP definitions give chemists a common reference point to describe how a gas behaves under “normal” conditions. Scientists use standards like STP definitions for two purposes, to define certain quantitative metrics and to allow for consistent and repeatable experiments.