You are Here: Home

# moles ppm watch

1. The nitrogen dioxide content of air on a particular day was 0.150 ppm by mass.
The density of the air was 1.225kgm−3.
What was the mass of nitrogen dioxide in 1m3
of air on that day?

A 1.83 × 10−7 kg
B 1.83 × 10−10 kg
C 1.84 × 10−7 kg
D 1.84 × 10−10 kg

2. A density of 1.225 kg m-3 means that a cubic metre has mass 1.225 kg.

Given that 0.150 mass units in a million are NO2, you can set up a proportion and solve for the missing term:
0.150 : 106 = x : 1.225 kg

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: March 5, 2018
Today on TSR

### He lied about his age

Thought he was 19... really he's 14

### University open days

Wed, 25 Jul '18
2. University of Buckingham
Wed, 25 Jul '18
3. Bournemouth University
Wed, 1 Aug '18
Poll

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE