As per as the Multiplication rules of the significant figures, whenever any numbers in the decimals forms are multiplied or divided then result in mentioned in such a way so that the significant figures after the decimal will be same as that in the given least condition.
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102900/12 = 8575
170 × 1.27 = 215.9
∴ (102,900 ÷ 12) + (170 × 1.27) = 8575 + 215.9
= 8790.9
Now, As per as Above rules, answer in correct significant figures will be = 8791.
Answer:
The answer to your question is given after the questions so I just explain how to get it.
Explanation:
a)
Get the molecular weight of Phosphoric acid
H₃PO₄ = (3 x 1) + (31 x 1) + (16 x 4)
= 3 + 31 + 64
= 98 g
98 g ----------------- 1 mol
0.045 g --------------- x
x = (0.045 x 1) / 98
x = 0.045 / 98
x = 0.00046 moles or 4.6 x 10 ⁻⁴
b)
Molarity = 
Molarity = 
Molarity = 0.0013 or 1.31 x 10⁻³
c)
Formula C₁V₁ = C₂V₂
V₁ = C₂V₂ / C₁
Substitution
V₁ = (0.0013)(1) / 0.01
Simplification and result
V₁ = 0.0013 / 0.1
V₁ = 0.13 l = 130 ml
There are several information's already given in the question. Based on the information's the answer can be easily deduced.
We know the formula
<span>P1*V1/T1 = P2*V2/T2
</span>
As the temperature is constant, so T1 and T2 can be negated. The formula changes to
<span>P1*V1 = P2*V2
</span>70 * 1 = 540 * V2
270/540 = V2
<span>V2 = 0.5
</span>
From the above deduction, we can conclude that the new volume is 0.5 liters. I hope that the procedure is clear enough for you to understand.
<span>2.10 grams.
The balanced equation for the reaction is
CO + 2H2 ==> CH3OH
The key thing to take from this equation is that it takes 2 hydrogen molecules per carbon monoxide molecule for this reaction. And since we've been given an equal number of molecules for each reactant, the limiting reactant will be hydrogen.
We can effectively claim that we have 5.86/2 = 2.93 l of hydrogen and an excess of CO to consume all of the hydrogen. So the number of moles of hydrogen gas we have is:
2.93 l / 22.4 l/mol = 0.130803571 mol
And since it takes 2 moles of hydrogen gas to make 1 mole of methanol, divide by 2, getting.
0.130803571 mol / 2 = 0.065401786 mol
Now we just need to multiply the number of moles of methanol by its molar mass. First lookup the atomic weights involved.
Atomic weight carbon = 12.0107 g/mol
Atomic weight hydrogen = 1.00794 g/mol
Atomic weight oxygen = 15.999 g/mol
Molar mass CH3OH = 12.0107 + 4 * 1.00794 + 15.999 = 32.04146 g/mol
So the mass produced is
32.04146 g/mol * 0.065401786 mol = 2.095568701 g
And of course, properly round the answer to 3 significant digits, giving 2.10 grams.</span>