A certain ore is 31.5% nickel by mass. How many kilograms of this ore would you need to dig up to have 70.0 g of nickel?

Question

jim_thompson5910 · Answer

If you want 70.0 g of pure nickel, then

31.5% of x = 70

0.315x = 70

x = ???


x is the amount of ore

moonlight93 · Answer

thank you , that helps alot

jim_thompson5910 · Answer

you're welcome

moonlight93 · Answer

what would be the answer after rounding to the significant figure ?? i got 222.22 kg as an answer. and it should be rounded to two significant number, how do i do that?

moonlight93 · Answer

@jim_thompson5910

jim_thompson5910 · Answer

rounding 222.22222... to 2 sig figs gives 220

the first '2's are significant while that 0 is not significant

jim_thompson5910 · Answer

now the issue here is that if you mine 220 g of ore, then you'll come up short

so you'll have to mine 230 g of ore (if you stick to 2 sig figs) so you make sure you have enough ore to get 70 g of nickel

moonlight93 · Answer

oh, ok, :) thank you.

moonlight93 · Answer

i converted 222.22g to kg and got a good answer

jim_thompson5910 · Answer

that works

222 g = 0.222 kg

round that to 2 sig figs to get 0.22 kg

then again, you need to mine 0.23 kg of ore to get 70 g of nickel