%error = |(original value - mistaken value)| / original value * 100%
Original value = 1.2 x 10^-12
Mistaken value = 1.7 x 10^-10
%error = | [(1.2 x 10^-12) - (1.7 x 10^-10)] | / 1.2 x 10^-12 x 100%
%error = (1.688 x 10^-10 / 1.2 x 10^-12) x 100%
%error = 1.172222222 x 10^17
To answer this we need to assume that at STP 1 mol of a substance is equal to 22.4 L. We use this data for the calculations.
Statement 1
2 mol HCl (1 mol H2 / 2 mol HCl) = 1 mol H2 thus at STP 22.4 L H2
<em>This statement is false.</em>
Statement 2
1 L Zn (1 mol Zn / 22.4 L Zn) (1 mol H2 / 1 mol Zn) (22.4 L H2 / 1 mol H2) = 1L H2
<em>This statement is true.</em>
Statement 3
65.39 g Zn (1 mol Zn / 65.39 g Zn) (1 mol H2 / 1 mol Zn) = 1 mol H2
<em>This statement is true.</em>
Statement 4
1L HCl (1 mol HCl / 22.4 L HCl)(1 mol H2 / 2 mol HCl) = 0.022 mol H2
<em>This statement is false.</em>
To solve this problem, we use Beer's Law: A= ε.l.c
A is the absorbance- 0,558
<span>ε is</span> the molar absorptivity- is <span>15000 </span><span><span>L⋅mol-1</span><span>cm-1</span></span>
<span>l is </span>the length of the cuvette- 1 cm
<span>c is</span> the molar concentration
Applying the formula,
0,558= 15000 x 1 x c
0,558/15000= c
c= <span>3.72×<span>10⁻⁵ </span> <span>mol⋅L<span>⁻¹</span></span></span>
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