Sample 1: 100 grams of water at 10 C

For temperatures between the freezing and boiling point of water, the heating curve is linear. Thus, we can use:

((200 * 90) + (100* 30))/300

Or: ((200 * 90)(temperature of first sample weighted by mass) + (100 * 30)(temperature of second sample weighted by mass) / (300)(total mass)

to find the final temperature.

100 can be factored out to get (2 * 90) + (1 * 30)) / 3

3 can be factored out every term: (2 * 30) + (1 * 10)

(The factoring out just makes mental math easier; if a calculator is available doing so is unnecessary.)

And then just work through the order of operations.

60 + 10

=70.

So in mathematics, which assumes a perfect world, you get 70.
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Randy Woods
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October 30, 2017

1. Translate, predict the products, and balance the equation above. 

Li + Cu(NO3)2 = Li(NO3)2 + Cu

2. How many particles of lithium are needed to produce 125 g of copper? 

125 g Cu ( 1 mol / 63.55 g ) (1 mol Li / 1 mol Cu ) ( 6.022 x 10^23 particles / 1 mol ) = 1.18x10^24 Li particles

3. How many grams of lithium nitrate are produced from 4.83E24 particles of copper (II) nitrate?

4.83E24 particles of copper (II) nitrate ( 1 mol / 6.022x10^23 particles ) (1 mol Li(NO3)2 / 1 mol Cu(NO3)2 ) ( 130.95 g / 1 mol ) = 1043.77 grams Li(NO3)2