A certain ore is 27.3% nickel by mass. How many kilograms of this ore would you need to dig up to have 40.0 g of nickel?

Answer 1

27.3% of what value (x) is equal to 40.0g?

0.273 x = 40.0 g

x = 146.5 g

Converting this to kg, we have...

146.5 g x 1 kg / 1000 g = 0.1465 kg = 0.147 kg (3 sig. figs.)

Answer 2

Hey Hannah,

You can just think of this as a ratio problem. So 27.3% is like saying that if you had 100g of ore, 27.3g would be Nickel. So, mathematically:

27.3g/100g = 40.0g/ x

Solve for x by cross-multiplying, and make sure to put the answer into kg when you're done.