The piece of unknown metal is in thermal equilibrium with water such that Q of metal is equal to Q of the water. We write this equality as follows:
-Qm = Qw
Mass of metal (Cm)(ΔT) = Mass of water (Cw) (ΔT)
where C is the specific heat capacities of the materials.
We calculate as follows:
-(Mass of metal (Cm)(ΔT)) = Mass of water (Cw) (ΔT)
-68.6 (Cm)(52.1 - 100) = 42 (4.184) (52.1 - 20)
Cm = 1.717 -----> OPTION C
Answer 2: 57.21235000000001
Answer 3: 44.01g
Answer 4: 24.645320000000005
Answer 5: 107.04578240000001
Good luck
Answer:
Tests for gases
Hydrogen, oxygen, carbon dioxide, ammonia and chlorine can be identified using different tests.
Hydrogen. A lighted wooden splint makes a popping sound in a test tube of hydrogen.
Oxygen. A glowing wooden splint relights in a test tube of oxygen.
hope it will help
The balanced equation would be 
<h3>Electrochemical equations</h3>
Zn reacts with Cu solution according to the following equation:
In the reaction, 
is reduced according to the following: 
While Zn is oxidized according to the following: 
Thus, giving the overall equation of;
More oxidation-reduction equations can be found here: brainly.com/question/13699873
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