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Eduardwww [97]
3 years ago
9

How many significant figures are in the measurement 40,500 mg?

Chemistry
1 answer:
schepotkina [342]3 years ago
3 0

b) three

this is because all integers are sig figs, and all numbers between integers are sig figs. This makes the 40,5 part of 40,500 significant. Place holder zeroes that are not after a decimal are not significant, so the last two zeroes of the number are not significant.

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Acetylene (c2h2) undergoes combustion in excess oxygen to generate gaseous carbon dioxide and water. given δh°f[co2(g)] = –393.5
Brums [2.3K]
Answer is: 13181,7 kJ of energy <span>is released when 10.5 moles of acetylene is burned.
</span>Balanced chemical reaction: C₂H₂ + 5/2O₂ → 2CO₂ + H₂O.
<span>ΔHrxn = sum of ΔHf (products of reaction) - sum of ΔHf (reactants).</span><span>
Or ΔHrxn = ∑ΔHf (products of reaction) - ∑ΔHf (reactants).
ΔHrxn - enthalpy change of chemical reaction.
<span>ΔHf - enthalpy of formation of reactants or products.
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8 0
3 years ago
2Fe(s) +3H2SO4(aq) →Fe2(SO4)3(aq) +3H2(g)When 10.3 g of iron are reacted with 14.8 moles of sulfuric acid, what is the percent y
Elden [556K]

Answer:

1040%

Explanation:

To solve this question we must convert the mass of Iron to moles in order to find limiting reactant. With limiting reactant we can find the theoretical moles of hydrogen and theoretical mass:

Percent yield = Actual yield (5.40g) / Theoretical yield * 100

<em>Moles Fe -Molar mass: 55.845g/mol-:</em>

10.3g * (1mol / 55.845g) = 0.184 moles of Fe will react.

For a complete reaction of these moles there are necessaries:

0.184 moles Fe* ( 3 mol H2SO4 / 2 mol Fe) = 0.277 moles H2SO4.

As there are 14.8 moles of the acid, <em>Fe is limiting reasctant.</em>

The moles of H2 produced are:

0.184 moles Fe* ( 3 mol H2 / 2 mol Fe) = 0.277 moles H2

The mass is:

0.277 moles H2 * (2.016g/mol) = 0.558g H2

Percent yield is:

5.40g / 0.558g * 100 = 1040%

It is possible the experiment wasn't performed correctly

7 0
3 years ago
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Answer:

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5 0
3 years ago
Two elements in the same period have the same number of _____ _____ in their electron clouds.
shutvik [7]

Answer:

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3 0
3 years ago
Read 2 more answers
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Thepotemich [5.8K]

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Explanation:

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8 0
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