Answer:
- 0.71963 g of Zn
- 0.80256 g of HCl
Step-by-step explanation:
The required mass of reactants can be computed from the number of moles of product.
moles of ZnCl₂ = (1.5 g)/(136.282 g) ≈ 0.0110066 moles
Then the mass of Zn required is ...
mass of Zn = (0.0110066 mol)(65.382 g/mol) = 0.71963 g
Two moles of HCl are used in the reaction with each mole of Zn, so the mass of HCl required is ...
mass of HCl = 2(0.0110066 mol)(36.458 g/mol) = 0.80256 g
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<em>Comment</em>
The discrepancy in the last two decimal places of the weights above versus the calculator output below comes from rounding of moles of Zn to 4 significant digits, instead of 5 or more. The number of moles of ZnCl₂ is closer to 0.0110066.
Hey You!
This question is asking us, "75 is 75% of what number?"
75 × 100 / 75 = 100
The original cost was $100.
Solving for x.
Add by to both sides
Ax=c+by
Divide both sides by a
x=c+by
-------
a
Answer:
both kinds of tickets are $5 each
Step-by-step explanation:
Let s and c represent the dollar costs of a senior ticket and child ticket, respectively. The problem statement describes two relationships:
12s + 5c = 85 . . . . . revenue from the first day of sales
6s + 9c = 75 . . . . . . revenue from the second day of sales
Double the second equation and subtract the first to eliminate the s variable.
2(6s +9c) -(12s +5c) = 2(75) -(85)
13c = 65 . . . . . simplify
65/13 = c = 5 . . . . . divide by the coefficient of c
Substitute this value into either equation. Let's use the second one.
6s + 9·5 = 75
6s = 30 . . . . . . . subtract 45
30/6 = s = 5 . . . divide by the coefficient of s
The price of a senior ticket is $5; the price of a child ticket is $5.