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3 years ago

Which refers to a method that relies on sound waves and is used by different animal species for navigation,

Chemistry

1 answer:

____ [38]3 years ago

8 0

Answer:

Explanation:

Echolocation

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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

Which word signals a nonrestrictive clause in a complex sentence? T F

djverab [1.8K]

Which.i think its the answer

7 0

3 years ago

8. A student passes a magnet over 10 g of a powder. Four grams of the powder stick to the magnet, while 6 g do not. Which of the

vladimir1956 [14]

Answer:

mixture

Explanation:

The properties of the components of substance are different. One component has magnetic properties, another does not. So, we have at least 2 individual substances that were mixed together. So, we have a mixture.

7 0

3 years ago

Read 2 more answers

Help ;-; Will give Brainliest and 25 Points

Yuri [45]

I don’t see what you need help with but thanks:)

3 0

3 years ago

Read 2 more answers

Help ASAP will give brainlist

Aleonysh [2.5K]

Answer:

1. 3.83 L

2. 0.368 mole

Explanation:

1. Determination of the volume

Pressure (P) = 3.21 atm

Temperature (T) = 202 K

Number of mole (n) = 0.741 mole

Gas constant (R) = 0.0821 L.atm/molK

Volume (V) =?

The volume can be obtained by using the ideal gas equation as illustrated below:

PV = nRT

3.21 × V = 0.741 × 0.0821 × 202

3.21 × V = 12.3497283

Divide both side by 3.21

V = 12.2888922 / 3.21

V = 3.83 L

Thus, the volume of the gas is 3.83 L

2. Determination of the number of mole.

Pressure (P) = 2.50 atm

Temperature (T) = 215 K

Volume (V) = 2.60 L

Gas constant (R) = 0.0821 L.atm/molK

Number of mole (n) =?

The number of mole can be obtained by using the ideal gas equation as illustrated below:

PV = nRT

2.50 × 2.60 = n × 0.0821 × 215

6.5 = n × 17.6515

Divide both side by 17.6515

n = 6.5 / 17.6515

n = 0.368 mole

Thus, the number of mole of the gas is 0.368 mole.

3 0

3 years ago