Question

If antique brass is 30.0% zinc and 70.0% copper, how many grams of antique brass can be made from 18.0 grams of zinc and 35.1 grams of copper?

Answer 1

can you explain it?

Answer 2

?

Answer 3

@aditya96

Answer 4

what do you mean if it's a chemistry question, what would be the difference

Answer 5

Your solution will be one of these:

1) Use all the zinc, but not all the copper.
2) Use all the copper, but not all the zink.
3) Use both completely. (This will be just luck.)

Let B = The number of ounces of brass that can be created

Use all the zinc

B*0.30 = 18.0 ==> B = 60 but this requires 60*0.70 = 42 oz of copper, and we've only 35.1

Use all the copper

B*0.70 = 35.1 ==> B = 50.14 and this requires 15.04 oz of zinc. I think we're done.

Answer 6

isn't that what I did?

Answer 7

No, @primeralph, you simple dropped some algebra and provided no explanation. Let's try harder to teach.

Answer 8

you meant to say grams, not ounces, right?

Answer 9

Obvious to whom? Obvious or not, we're teaching methods and thought processes, here. It's about helping students to see, not just telling that they should see.

Answer 10

Right. Sorry about that. Normally I would check the units quite carefully, but everything was the same in this problem, so I guess I fell asleep on that point. Apologies.

Answer 11

So my final answer would be 50.14?

Answer 12

ahahaha - No! Where are your units?! Didn't you just call me on that? :-)

Answer 13

Oh man I'm so confused. I'm sorry!

Answer 14

nevermind I got it!

Answer 15

No, I'm not going to interrupt, you can continue. But it would be so much simpler if you noticed the ratio