What is the concentration in parts per million of a 500 g sample of drinking water that contains 45 mg of lead?

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Answer 1 · 2018-02-14T02:51:42

$90 ppm$ $"90 ppm"$

PPM can be better understood in typical units of concentration!

PPM can also be represented as mg/L!

Assuming the density of water is 1.0g/ml, we can translate 500.0g of water to be 500.0mL of water!

Therefore,

Turning 500.0mL of water into L first;

$500 mL \cdot \frac{1 L}{1000 mL} = 0.5 L$ $"500 mL" * "1 L"/"1000 mL" = "0.5 L"$

For PPM, we want to keep our mass in mg, which was already supplied!

As such,

$\frac{45 mg}{0.5 L} = 90 mg/L = 90 ppm$ $"45 mg" /"0.5 L" = "90 mg/L" = "90 ppm"$