Tick (√) the statements that are correct.

Kemmi Major does some experimental work on the combustion of sucrose: C12H22O11(s) 12 O2(g) → 12 CO2(g) 11 H2O(g) She burns a 0.

Pavlova-9 [17]

Answer: $5.81\times 10^6J/mol$

Explanation:

Heat of combustion is the amount of heat released when 1 mole of the compound is completely burnt in the presence of oxygen.

$C_{12}H_{22}O_{11}(s)+12O_2\rightarrow 12CO_2(g)+11H_2O(g)$

To calculate the moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{0.05392g}{342g/mol}=1.577\times 10^{-4}moles$

Thus $1.577\times 10^{-4}moles$ of sucrose releases = 916.6 J of heat

1 mole of sucrose releases = $\frac{916.6}{1.577\times 10^{-4}}\times 1=5.81\times 10^6J$ of heat

Thus ∆H value for the combustion reaction is $5.81\times 10^6J/mol$

6 0

3 years ago

What is the main advantage of using ethanol

natka813 [3]

Answer:

Overall, ethanol is considered to be better for the environment than petrol. Ethanol-fuelled vehicles produce lower carbon dioxide emissions, and the same or lower levels of hydrocarbon and oxides of nitrogen emissions.

Explanation:

5 0

3 years ago

In the reaction CuO(s) + CO2(g) → CuCO3(s), a. CO2 is the Lewis acid and CuCO3 is its conjugate base. b. O2– acts as a Lewis bas

adoni [48]

Answer: The correct answer is Option d.

Explanation:

According to Lewis acid-base concept:

The substance which is donating electron pair is considered as Lewis base and the substance which is accepting electron pair is considered as Lewis acid.

For the given chemical reaction:

$CuO(s)+CO_2(g)\rightarrow CuCO_3(s)$

$CO_2$ is accepting electron pair and is getting converted to $CO_3^{2-}$ . Thus, it is considered as Lewis acid.

$O^{2-}$ present in CuO is a Lewis base because it is donating electron pair.

Thus, the correct answer is Option d.

4 0

3 years ago

. An atom of nitrogen has an atomic

GrogVix [38]

Here's the Answer !

Atomic number = no. of electrons = no. of protons, therefore :

no. of electrons = 7

no. of protons = 7

and mass number = no. of protons + no. of neutrons

so,

7 + no. of neutrons = 14

no. of neutrons = 7

5 0

3 years ago

Gold is alloyed (mixed) with other metals to increase its hardness in making jewelry.

KiRa [710]

Answer:

A) 54.04%

B) 13-karat

Explanation:

A) From the problem we have

1) Mg + Ms = 9.40 g

2) Vg + Vs = 0.675 cm³

Where M stands for mass, V stands for volume, and g and s stand for gold and silver respectively.

We can rewrite the first equation using the density values:

3) Vg * 19.3 g/cm³ + Vs * 10.5 g/cm³ = 9.40

So now we have a system of two equations (2 and 3) with two unknowns:

We express Vg in terms of Vs:

Vg + Vs = 0.675 cm³

Vg = 0.675 - Vs

We replace the value of Vg in equation 3:

Vg * 19.3 + Vs * 10.5 = 9.40

(0.675-Vs) * 19.3 + Vs * 10.5 = 9.40

13.0275 - 19.3Vs + 10.5Vs = 9.40

-8.8 Vs + 13.0275 = 9.40

Vs = 0.412 cm³

Now we calculate Vg:

Vg + Vs = 0.675 cm³

Vg + 0.412 cm³ = 0.675 cm³

Vg = 0.263 cm³

We calculate Mg from Vg:

0.263 cm³ * 19.3 g/cm³ = 5.08 g

We calculate the mass percentage of gold:

5.08 / 9.40 * 100% = 54.04%

B)

We multiply 24 by the percentage fraction:

24 * 54.04/100 = 12.97-karat ≅ 13-karat

4 0

3 years ago