Question

Nitrogen is found in dry air at sea level at a concentration of 78.1 percent by volume. What is the concentration of nitrogen expressed in parts per million (ppm)?

a) 781 ppm
b) 7810 ppm
c) 78100 ppm
d) 781000 ppm

Answer 1

The concentration of nitrogen in dry air at sea level is 78.1 percent by volume, which is equal to 781,000 ppm.

Step-by-step explanation:

The concentration of nitrogen in dry air at sea level is 78.1 percent by volume. To express this concentration in parts per million (ppm), you need to understand that 1 percent by volume is equivalent to 10,000 ppm (since 1% of a million is 10,000). Therefore, to convert the percentage to ppm, you simply multiply by 10,000:

78.1% × 10,000 = 781,000 ppm

So the correct concentration of nitrogen expressed in ppm is 781,000 ppm, which aligns with option d).