It was the element of aluminium where they predict their properties <span />
The bottom of a cricket wing is covered with teeth-like ridges that make<span> it rough. The upper surface of the wing is like a scraper. When </span>crickets<span> rub the upper and lower parts of their wings together, they create a chirping</span>sound<span> called “stridulating."</span>
<span>Answer: 100 ml
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<span>Explanation:
1) Convert 1.38 g of Fe₂S₃ into number of moles, n
</span>i) Formula: n = mass in grass / molar mass
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ii) molar mass of </span><span>Fe₂S₃ =2 x 55.8 g/mol + 3 x 32.1 g/mol = 207.9 g/mol
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iii) n = 1.38 g / 207.9 g/mol = 0.00664 moles of <span>Fe₂S₃
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<span>2) Use the percent yield to calculate the theoretical amount:
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<span>65% = 0.65 = actual yield/ theoretical yield =>
</span>theoretical yield = actual yield / 0.65 = 0.00664 moles / 0.65 = 0.010 mol <span>Fe₂S₃</span><span>
3) Chemical equation:
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<span> 3 Na₂S(aq) + 2 FeCl₃(aq) → Fe₂S₃(s) + 6 NaCl(aq)
4) Stoichiometrical mole ratios:
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<span>3 mol Na₂S : 2 mol FeCl₃ : 1 mol Fe₂S₃ : 6 mol NaCl
5) Proportionality:
</span>2moles FeCl₃ / 1 mol Fe₂S₃ = x / 0.010 mol Fe₂S₃
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=> x = 0.020 mol FeCl₃
6) convert 0.020 mol to volume
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<span>i) Molarity formula: M = n / V
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<span>ii) V = n / M = 0.020 mol / 0.2 M = 0.1 liter = 100 ml
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The equation for calculating a mass is as follows:
m=n×M
Molar mass (M) we can determine from Ar that can read in a periodical table, and a number of moles we can calculate from the available date for N:
n(H2SO4)=N/NA
n(H2SO4)= 1.7×10²³ / 6 × 10²³
n(H2SO4)= 0.3 mole
Now we can calculate a mass of H2SO4:
m(H2SO4) = n×M = 0.3 × 98 = 27.8 g
For the answer to the question above, <span>ater weights 1000kg per meter cubed. the volume of the pool is part A is 5*4*3 = 60 meters cubed </span>
<span>60*1000 = 60 000kg. the force from this is m*g = 60 000 * 9.81 = 588kN </span>
<span>part B: </span>
<span>volume: 4*4*3 = 48 meters cubed </span>
<span>48 * 1000 = 48000kg </span>
<span>F = 9.81*48000 = 470kN
I hope this helps.</span>
