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.