Answer: 12.18 u
Explanation: The average atomic mass of an element is calculated by taking the weighted average of the atomic masses of its stable isotopes.
In other words, each stable isotope will contribute to the average mass of the element proportionally to its abundance.
The correct answer is D. The solute in this solution is the solid sodium nitrate (NaNO3) which is dissolved in the solvent, the water. Solute is the minor component in a solution whereas the solvent is the major component in the solution.
substitute: <span><span>t<span>1/2</span></span>=<span><span>ln(2)</span>k</span>→k=<span><span>ln(2)</span><span>t<span>1/2</span></span></span></span>
Into the appropriate equation: <span>[A<span>]t</span>=[A<span>]0</span>∗<span>e<span>−kt</span></span></span>
<span>[A<span>]t</span>=[A<span>]0</span>∗<span>e<span>−<span><span>ln(2)</span><span>t<span>1/2</span></span></span>t</span></span></span>
<span>[A<span>]t</span>=(250.0 g)∗<span>e<span>−<span><span>ln(2)</span><span>3.823 days</span></span>(7.22 days)</span></span>=67.52 g</span>
Na₃PO₄ -----> 3Na(+) + PO₄(3-)
y-y.......................3y...........y
3y = 1.2
y = 0,4M
Na₃PO₄ -----> 3Na(+) + PO₄(3-)
0,4-0,4..............1,2..........0,4
0.........................1,2..........0,4
C = n/V
n = C×V
n = 0,4×0,65L
n = 0,26 mol Na₃PO₄
mNa₃PO₄: (23×3)+31+(16×4) = 164 g/mol
164g ----- 1 mol
Xg -------- 0,26 mol
X = 164×0,26
X = 42,64g Na₂SO₄
Thickness of cooper sheet is 0.048 cm (Approx.)
Given that;
Density of copper = 8.96 g/cm³
Measures of copper sheet = 5.5 cm × 5.5 cm
Mass of of copper sheet = 12.96 gram
Find:
Thickness of cooper sheet
Computation:
Volume = Mass / Density
Volume of cooper = 12.96 / 8.96
Volume of cooper = 1.4464
Volume of cooper = 1.45 cm³ (Approx.)
Volume of cooper sheet = 5.5 cm × 5.5 cm x Thickness
5.5 cm × 5.5 cm x Thickness = 1.45
Thickness of cooper sheet = 0.04793
Thickness of cooper sheet = 0.048 cm (Approx.)
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