Question

What is the minimum mass of hubnerite (MnWO4), a tungsten ore, from which 95.0 g of pure tungsten could be extracted?

Answer 1

From one mole of MnWO4, we get one mole of tungsten. Therefore 10.88 mol of tungsten will be obtained from 10.88 mol of MnWO4.

Molar mass MnWO4 = 54.94 + 183.84 + 4(16.0) = 302.78 g.mol-1

Therefore mass of MnWO4 required = mole x molar mass = 10.88 mol x 302.78 g.mol-1 = 3294.24 grams

And, 3294.24 grams = > 3.29424 kg

On rounding off to two significant digits, we get 3.3 kg.

Rounds a number to 3 significant digits the same way it rounds to 3 decimal places. Count up to 3 digits from the first non-zero digit. Then round off the last digit. Pad the remaining digits to the right of the decimal point with zeros. 0.0560 has 3 significant digits. In accordance with scientific conventions, leading zeros in decimal numbers are not treated as significant. So exclude 0.0 from 0.0560.

Learn more about Significant digits here:-brainly.com/question/28052368

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