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3 years ago

PLEASE HELP FOR 15 BRAINY POINTS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Chemistry

1 answer:

evablogger [386]3 years ago

6 0

Answer:

i dont know sorry

Explanation:

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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 are the three states in which most matter occurs

Mrrafil [7]

Solid, liquid, and gas.

4 0

3 years ago

Read 2 more answers

Need help fast !!!!!!!

Sveta_85 [38]

Answer:

Brittle

Explanation:

because thas for non metals

6 0

3 years ago

Read 2 more answers

One problem caused by technology is pollution

balandron [24]

I think this is true because..

technology negatively affects the environment by compromising human health and safety... endangering natural ecosystem and biodiversity... having a cumulative impact on global systems... and depleting natural resources. Technology positively affects the environment through the application of environmental science to solve problems caused by human environmental impact.

Risks to humans from environmental damage through technology include inhalation of dangerous chemicals in air pollution, contamination of water and food sources, and risk of infections and diseases through exposure to toxic wastes. Flora and fauna risk habitat loss or disruption and extinction of species through exposure to dangerous byproducts of technology. Greenhouse gases affect atmosphere and weather systems, causing global warming and chlorofluorocarbons that deplete the Earth's ozone layer. Technology consumes resources which are not necessarily renewable, including living resources, such as forests and populations of fish, and inanimate resources, such as natural chemicals and minerals.

Although technology damages the environment in many ways..it can also have the capability to limit or prevent damage using such environmental technologies such as recycling...the exploitation of renewable energy sources such as solar power and wind power... the purification of polluted air and water,and the treatment of sewage and factory wastes.. and the development and production of devices that promote energy conservation.....so this is why i think this is the answer! ☺

Hopefully this helped you!☺

4 0

4 years ago

List and explain the four most important factors that control the relative reactivity of a carbonyl-containing functional group

ioda

Resonance, leaving group, carbonyl carbon delta+, and steric effect is the most crucial variables that affect the relative reactivity of a functional group containing a carbonyl in an addition or substitution process.

Discussion:

1. Carbonyl Carbon Delta+: The carbonyl group becomes more electrophilic and accelerates nucleophilic assault when the carbonyl carbon delta+ is bigger.

2. Resonance: When the carbonyl is transformed into the tetrahedral adduct, it may be lost. Loss of resonance increases the energy of the transition state for this nucleophilic assault because resonance has the function of stabilizing. Therefore, a carbonyl functional group's resistance to nucleophilic attack increases as resonance in the group increases in importance.

3. Leaving group: Tetrahedral adduct fragmentation is encouraged by a better LG.

4. Steric effects: The nucleophilic attack on carbonyl carbon is delayed when sterically impeded.

Learn more about carbonyl here:

brainly.com/question/21440134

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8 0

1 year ago