Help me with this, please

A 21.8 g sample of ethanol (C2H5OH) is burned in a bomb calorimeter, according to the following reaction. If the temperature ris

Blababa [14]

Answer: The heat capacity of calorimeter is $15.66J/^oC$

Explanation:

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

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

Given mass of ethanol = 21.8 g

Molar mass of ethanol = 46.07 g/mol

Putting values in above equation, we get:

$\text{Moles of ethanol}=\frac{21.8g}{46.07g/mol}=0.473mol$

To calculate the enthalpy change of the reaction, we use the equation:

$\Delta H_{rxn}=\frac{q}{n}$

where,

$q$ = amount of heat released = ?

n = number of moles = 0.473 moles

$\Delta H_{rxn}$ = enthalpy change of the reaction = -1235 kJ/mol = $-1235\times 10^3J/mol$ (Conversion factor: 1 kJ = 1000 J)

Putting values in above equation, we get:

$-1235\times 10^3J/mol=\frac{q}{0.473mol}\\\\q=(-1235\times 10^3J/mol\times 0.473mol)=-584.16\times 10^3J$

To calculate the heat capacity of calorimeter, we use the equation:

$q=c\Delta T$

where,

q = heat absorbed by the calorimeter = $584.16\times 10^3J$

c = heat capacity = ?

$\Delta T$ = change in temperature = $T_2-T_1=62.3^oC-25^oC=37.3^oC$

Putting values in above equation, we get:

$584.16\times 10^3J=c\times 37.3^oC\\\\c=\frac{584.16\times 10^3J}{37.3^oC}=15.66J/^oC$

Hence, the heat capacity of calorimeter is $15.66J/^oC$

4 0

4 years ago

Calculate the pH of the solution formed when 45.0 mL of 0.100M NaOH solution is added to 50.0 mL of 0.100M CH3COOH (Ka for aceti

pav-90 [236]

Answer:

pH of soltion will be 5.69

Explanation:

The pH of the solution will be due to excessive acid left and the salt formed. Thus, it will form a buffer solution.

The pH of buffer solution is calculated from Henderson Hassalbalch's equation, which is:

$pH=pKa+log(\frac{[salt]}{[acid]} )$

$pKa=-log(Ka)$

$pKa=-log(1.8X10^{-5})=4.74$

The moles of acid taken :

$moles=molarityXvolume=0.1X50=5mmol$

The moles of base taken:

$moles=molarityXvolume=0.1X45=4.5mmol$

The moles of acid left after reaction :

$5-4.5=05mmol$

The moles of salt formed = 4.5mmol

Putting values in equation

$pH=pKa+log(\frac{[salt]}{[acid]} )=4.74+log(\frac{4.5}{0.5})=5.69$

8 0

3 years ago

A app181.studyisland.com

grandymaker [24]

C. At some point, the land masses were connected to each other.

Explanation:

The fossils now exists far away from each other because at some point, the land masses were once connected to each other. Now, the land masses have drifted apart due to plate tectonics.

Alfred Wegener a scientist in 1912 first formulated the theory of continental drift. The theory suggests that present day land masses have moved to their present positions.

A more refined theory of plate tectonics is now in play today and it provides a better understanding to why we can find similar features across different continents.
The similar fossils must have formed together when the land masses were once joined together.
Noe that the land masses are separated, the fossils species are not separated.

learn more:

Continental drift brainly.com/question/5002949

#learnwithBrainly

8 0

3 years ago

A solid calcium metal reacts with molecular oxygen. WORD EQUATION = CHEMICAL EQUATION =

Ne4ueva [31]

Word equation - calcium + oxygen -> calcium oxide
Chemical equation - Ca + O2 -> CaO2

Hope this helps!

5 0

3 years ago

How many grams of CO2 are produced from the burning of 1.0 mol of amyl alcohol, C5H11OH?

Keith_Richards [23]

Answer:

220g of CO2

Explanation:

Step 1:

The balanced equation for the reaction.

2C5H11OH + 15O2 —> 10CO2 + 12H2O

Step 2:

Determination of the number of mole of CO2 produced by burning 1 mole of C5H11OH.

From the balanced equation above,

2 moles of C5H11OH produced 10 moles CO2.

Therefore, 1 mole of C5H11OH will produce = (1 x 10)/2 = 5 moles of CO2.

Therefore, 5 moles of CO2 is produced from the reaction.

Step 3:

Conversion of 5 moles of CO2 to grams.

Molar mass of CO2 = 12 + (2x16) = 44g/mol

Number of mole of CO2 = 5 moles

Mass of CO2 =...?

Mass = mole x molar mass

Mass of CO2 = 5 x 44

Mass of CO2 = 220g.

Therefore, 220g of CO2 were obtained from the reaction.

8 0

4 years ago