<span>1. Balance the reaction
Cu + 2AgNO3 → Cu(NO3)2 + 2Ag
2. Find the limiting [divide moles of reactant by their balancing numbers]
Cu: 4.2/1 =4.2
AgNO3: 6.3/2= 3.15
AGNO3 is the limiting
How many moles of silver metal will be formed?
The ratio between the limiting reactant and silver is 2:2 or 1:1
therefore 6.3 moles of silver will be formed.
How many moles of excess reactant will be left?
Since each mole of copper is equal to 2 moles of AgNO3. divide 6.3 by 2 then minus it from coppers moles
6.3/2 = 3.15
4.2-3.15 = 1.05 moles of copper will be left
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Answer:
1.2 moles
Explanation:
this is the balanced equation for the reaction of oxygen (O2) and hydrogen (H2), usually we don't write the 1 in front of O2
2H₂ + 10₂ → 2H₂O
the molar ratio of hydrogen to oxygen is 2 : 1
we are trying to react with 2.4 mol of H2 so the moles of O2 is half the number of moles of H2 = 2.4 ÷ 2 = 1.2 mol
another way to think of it:
2H₂ + 10₂
2 : 1
2.4 mol : x mol
to get from 2 to 2.4 multiply by 1.2, so do the same to the other side
1 × 1.2 = 1.2 mol
A. is definitely true. The age of the plants and the amount of caffeine are two variables. The experimenter should have used only plants of the same age in order to determine the effect of caffeine.
b. is wrong. The amount of caffeine used was a variable.
c. is wrong. Temperature, water, and light were constants.
d. is wrong. The statement is a hypothesis that the experiment is trying to prove
Answer:

Explanation:
Hello there!
In this case, for these problem about the colligative property of freezing point depression, it is possible set up the following equation:

Whereas the van't Hoff's factor, i, is 2 since KCl is ionized in two ions (K+ and Cl-); and the molality (m) of the solution is computed by:

Thus, since the freezing point of water (ice) is 0°C, we obtain the following freezing point of the solution by plugging in:

Best regards!
B. because it is the only one that makes sense