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3 years ago

#3 of thermo terms

Chemistry

1 answer:

Evgesh-ka [11]3 years ago

4 0

Answer:

Explanation:

If the enthalpy change (i.e. ΔH) of a reaction is negative, then the reaction releases heat and is hence exothermic.

Hence, our answer is C.

Conversely, if ΔH is positive, the reaction absorbs heat and is endothermic.

ΔH tells us nothing about the speed of the reaction.

While ΔH influences free-energy change (ΔG = ΔH - TΔS), we cannot predict the sign of ΔG given only ΔH (recall that a reaction is spontaneous if ΔG < 0).

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Solid aluminum and gaseous oxygen react in a combination reaction to produce aluminum oxide: 4Al (s) + 3O2 (g) â†’ 2Al2O3 (s) In

jek_recluse [69]

Answer: The percent yield of the reaction is 74 %

Explanation:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

$\text{Moles of aluminium}=\frac{2.5g}{27g/mol}=0.092mol$

For oxygen gas:

$\text{Moles of oxygen gas}=\frac{2.5g}{32g/mol}=0.078mol$

The chemical equation for the reaction of titanium and chlorine gas follows:

$4Al(s)+3O_2(g)\rightarrow 2Al_2O_3(s)$

By Stoichiometry of the reaction:

4 moles of aluminium reacts with 3 moles of oxygen.

So, 0.092 moles of aluminium reacts with = $\frac{3}{4}\times 0.092=0.069mol$ of oxygen

As, given amount of oxygen is more than the required amount. So, it is considered as an excess reagent.

Thus, aluminium is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

4 moles of aluminium produce = 2 moles of $Al_2O_3$

So, 0.092 moles of aluminium will produce = $\frac{2}{4}\times 0.092=0.046moles$ of $Al_2O_3$

Now, calculating the mass of aluminium oxide:

$\text{Mass of aluminium oxide}=moles\times {\text {molar mas}}=0.046mol\times 102g/mol=4.7g$

To calculate the percentage yield of titanium (IV) chloride, we use the equation:

$\%\text{ yield}=\frac{\text{Experimental yield}}{\text{Theoretical yield}}\times 100$

Experimental yield = 3.5 g

Theoretical yield = 4.7 g

Putting values in above equation, we get:

$\%\text{ yield of reaction}=\frac{3.5g}{4.7g}\times 100\\\\\% \text{yield of reaction}=74\%$

Hence, the percent yield of the reaction is 74 %

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Answer:

definition -

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the breakdown of a compound into oppositely charged ions

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The principle of conservation of matter states that matter is neither created nor destroyed, but it can _____.

kifflom [539]

... change its form, such as the phases of matter, or convert into energy.

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A solution of cough syrup contains 5.00% active ingredient by volume. If the total volume of the bottle is 31.0 mL, how many mil

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Answer:

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Explanation:

Data

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Solve for volume of solute

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