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4 years ago

Most of the costs associated with using renewable resources are due to

Chemistry

1 answer:

saveliy_v [14]4 years ago

6 0

Answer:

a. overuse of resources is the correct answer.

Explanation:

Renewable resources are available and they are abundant but overuse of these renewable resources will have a negative effect on the surroundings and humans.

Overuse of renewable resources will leads to the depletion of these renewable sources in the future and will also make the ecosystem unbalance.

Renewable resources are solar energy, geothermal energy, biomass energy, wind energy, hydro energy.

Thus renewable resources are threatened due to overuse and it must be carefully used.

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Calculate the mass of methane that must be burned to provide enough heat to convert 242.0 g of water at 26.0°C into steam at 101

Anarel [89]

Answer: The mass of methane burned is 12.4 grams.

Explanation:

The chemical equation for the combustion of methane follows:

$CH_4(g)+2O_2(g)\rightarrow CO_2(g)+2H_2O(g)$

The equation for the enthalpy change of the above reaction is:

$\Delta H^o_{rxn}=[(1\times \Delta H^o_f_{(CO_2(g))})+(2\times \Delta H^o_f_{(H_2O(g))})]-[(1\times \Delta H^o_f_{(CH_4(g))})+(2\times \Delta H^o_f_{(O_2(g))})]$

We are given:

$\Delta H^o_f_{(H_2O(g))}=-241.82kJ/mol\\\Delta H^o_f_{(CO_2(g))}=-393.51kJ/mol\\\Delta H^o_f_{(CH_4(g))}=-74.81kJ/mol\\\Delta H^o_f_{O_2}=0kJ/mol$

Putting values in above equation, we get:

$\Delta H^o_{rxn}=[(1\times (-393.51))+(2\times (-241.82))]-[(1\times (-74.81))+(2\times (0))]\\\\\Delta H^o_{rxn}=-802.34kJ$

The heat calculated above is the heat released for 1 mole of methane.

The process involved in this problem are:

$(1):H_2O(l)(26^oC)\rightarrow H_2O(l)(100^oC)\\\\(2):H_2O(l)(100^oC)\rightarrow H_2O(g)(100^oC)\\\\(3):H_2O(g)(100^oC)\rightarrow H_2O(g)(101^oC)$

Now, we calculate the amount of heat released or absorbed in all the processes.

For process 1:

$q_1=mC_p,l\times (T_2-T_1)$

where,

$q_1$ = amount of heat absorbed = ?

m = mass of water = 242.0 g

$C_{p,l}$ = specific heat of water = 4.18 J/g°C

$T_2$ = final temperature = $100^oC$

$T_1$ = initial temperature = $26^oC$

Putting all the values in above equation, we get:

$q_1=242.0g\times 4.18J/g^oC\times (100-(26))^oC=74855.44J$

For process 2:

$q_2=m\times L_v$

where,

$q_2$ = amount of heat absorbed = ?

m = mass of water or steam = 242 g

$L_v$ = latent heat of vaporization = 2257 J/g

Putting all the values in above equation, we get:

$q_2=242g\times 2257J/g=546194J$

For process 3:

$q_3=mC_p,g\times (T_2-T_1)$

where,

$q_3$ = amount of heat absorbed = ?

m = mass of steam = 242.0 g

$C_{p,g}$ = specific heat of steam = 2.08 J/g°C

$T_2$ = final temperature = $101^oC$

$T_1$ = initial temperature = $100^oC$

Putting all the values in above equation, we get:

$q_3=242.0g\times 2.08J/g^oC\times (101-(100))^oC=503.36J$

Total heat required = $q_1+q_2+q_3=(74855.44+546194+503.36)=621552.8J=621.552kJ$

To calculate the number of moles of methane, we apply unitary method:

When 802.34 kJ of heat is needed, the amount of methane combusted is 1 mole

So, when 621.552 kJ of heat is needed, the amount of methane combusted will be = $\frac{1}{802.34}\times 621.552=0.775mol$

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

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Molar mass of methane = 16 g/mol

Moles of methane = 0.775 moles

Putting values in above equation, we get:

$0.775mol=\frac{\text{Mass of methane}}{16g/mol}\\\\\text{Mass of methane}=(0.775mol\times 16g/mol)=12.4g$

Hence, the mass of methane burned is 12.4 grams.

8 0

3 years ago

What is the mass, in grams, of solute in 255mL of a 0.0525M solution of KMnO4 (MM =

aliya0001 [1]

Answer:

Mass = 2.12 g

Explanation:

Given data:

Volume of KMnO₄ = 255 mL (255/1000 = 0.255 L)

Molarity = 0.0525 M

Mass in gram = ?

Solution:

First of all we will calculate the number of moles.

Molarity = number of moles of solute / volume in litter

0.0525 M = number of moles of solute / 0.255 L

Number of moles of solute = 0.0525 M ×0.255 L

Number of moles of solute = 0.0134 mol

Mass in gram:

Number of moles = mass/ molar mass

Mass = moles × molar mass

Mass = 0.0134 mol × 158.04 g/mol

Mass = 2.12 g

7 0

3 years ago

Balancing Practice (some of these may be in the simulation)

agasfer [191]

Answer:

see below

Explanation:

16. 1 P₄(s) + 6 F₂(g) → 1 PF₃(s)

17. 2 C(s) + 2 H₂O(g) → 1 CH₄(g) + 1 CO₂(g)

18. 2 HgO(s)→ 1 O₂(g) + 2 Hg(l)

19. 1 CaCO₃(s) → 1 CO₂(g) + 1 CaO(s)

8 0

3 years ago

K for enolization of 2,4-cyclohexadienone is about 1013. Explain why the enol is so much more stable than the keto tautomer.

torisob [31]

Answer:

Because the value of K is huge.

Explanation:

The tautomer is a kind of isomer in which exist an equilibrium between a ketone and an enol, or between an aldehyde and an enol. So, in the enolization, the ketone is the reactant and the enol is the product.

The equilibrium reaction can be characterized by an equilibrium constant, which is the ratio of the concentration of the products by the concentration of the reactants.

Because the constant K is extremely large (10¹³) we can conclude that the concentration of the product will be greater than the concentration of the reactant, in the equilibrium. It means that the concentration of the enol will be greater.

So, the ketone is unstable and forms in a great amount the more stable product, the enol.

4 0

3 years ago

Which compound has the highest percent composition by mass of strontium

8090 [49]

So if the compound has the smallest gram formula mass it has the highest percentage composition by mass of strontium

3 0

3 years ago