Answer:
9.8g
Explanation:
Using periodic table find molar mass of C and H:
C=12.01g/mol
H=1.008g/mol
Molar mass of C2H4=(12.01)2+(1.008)4=28.03g/mol
Using molar mass times moles of the chemical to find the mass in 0.35 moles of c2h4:
28.03 x 0.35=9.8grams
Answer: [B]: 12.0 .
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Note: The pH scale ranges from 1 to 14 .
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Answer:
(102 900 ÷ 12) + (170 × 1.27) = 8800
Step 1. Evaluate the expressions inside the parentheses (PEMDAS)
102 900 ÷ 12 = 8575
170 × 1.27 = 215.9
In multiplication and division problems, your answer can have no more significant figures than the number with the fewest significant figures.
Thus, the underlined digits are not significant, but we keep them in our calculator to avoid roundoff error.
Step 2. Do the addition (PEMDAS).
8575
+ 215.9
= 8790.9
Everything that you add to an insignificant digit gives an insignificant digit as an answer.
Thus, the underlined digits are not significant.
We must drop them and round up the answer to 8800.
Explanation: