Answer:
0.0400M of KI
Explanation:
Molarity is an unit of concentration defined as the ratio between moles of solute and liters of solution.
When you add 10.0 mL of 0.10M KI and 15.0mL, total volume is:
25.0mL = <em>0.025L of solution</em>
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And moles of KI are:
0.0100L × 0.10M = <em>0.00100 moles of KI</em>
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Thus, molarity is:
0.00100 moles / 0.025L = <em>0.0400M of KI</em>
The oxidation numbers for Nitrogen are respectively -3, +5, +4
Answer: B) 46.7% Si and 53.3% O
Explanation:
To calculate the mass percent of element in a given compound, we use the formula:

Mass of quartz
= 5.05 g
Mass of silicon = 2.36 g
Mass of oxygen = Mass of quartz
- mass of silicon = 5.05g - 2.36 g = 2.69 g


Thus the percentages of silicon and oxygen in quartz are B) 46.7% Si and 53.3% O
Answer is: 3,94 of hydrogen gas.
Chemical reaction: 2K + 2HBr → 2KBr + H₂.
n(K) = 9,87 mol.
n(H₂) = ?.
from reaction: n(K) : n(H₂) = 2 : 1.
9,87 mol : n(H₂) = 2 : 1
n(H₂) = 4,935 mol for 100% yield of reaction
n(H₂) = 4,935 · 0,798 = 3,94 mol for 78,9 % yield of reaction.
n - amount of substance