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Black_prince [1.1K]

2 years ago

5

the energy transformation that occurs when a firework goes off is a chemical to thermal to light and sound. however, some of the

energy is destroyed during the explosion

1 answer:

quester [9]2 years ago

7 0

Answer:

false

Explanation:

energy can't be destroyed

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When a 0.245-g sample of benzoic acid is combusted in a bomb calorimeter, the temperature rises 1.643 ∘C . When a 0.260-g sample

sveticcg [70]

Answer:

The heat of combustion per moles of caffeine is 4220 kJ/mol

Explanation:

Step 1: Data given

⇒ When benzoic acid sample of 0.245 grams is burned the temperature rise is 1.643 °C

⇒ When 0.260 gram of caffeine is burned, the temperature rise is 1.436 °C

⇒ Heat of combustion of benzoic acid = 26.38 kJ/g

<u>Step 2:</u> Calculate the heat released: for combustion of benzoic acid

0.245 g benzoic acid * 26.38 kJ/g = 6.4631 kJ

<u>Step 3</u>: Calculate the heat capacity of the calorimeter:

c = Q/ΔT

Q = 6.4631 kJ / 1.643°C = 3.934 kJ/ °C

<u>Step 4:</u> Calculate moles of a 0.260 g sample of caffeine:

Moles caffeine = Mass caffeine / Molar mass caffeine

0.260 grams/ 194.19 g/mol = 0.0013389 moles

Step 5: Calculate heat released: for combustion of caffeine

Q = c * ΔT

Q = 3.934 kJ/°C * 1.436 °C = 5.65 kJ

Step 6: Calculate the heat of combustion per mole of caffeine

5.65 kJ / 0.0013389 moles = 4219.9 kJ/mol ≈ 4220 kJ/mol

The heat of combustion per moles of caffeine is 4220 kJ/mol

4 0

3 years ago

How many days the average menstrual cycle lastas

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3 years ago

6 moles of H2O is equal to how many molecules?

alexandr1967 [171]

6 miles of H2O is equal to 12 Hydrogen molecules and 6 oxygen molecules. Equaling 18 in total.

5 0

3 years ago

A 72.0 mL aliquot of a 1.40 M solution is diluted to a total volume of 248 mL. A 124 mL portion of that solution is diluted by a

Aliun [14]

Answer: 0.20 M

Explanation:

According to the dilution law,

$M_1V_1=M_2V_2$

where,

$M_1$ = molarity of stock solution = 1.40 M

$V_1$ = volume of stock solution = 72.0 ml

$M_2$ = molarity of diluted solution = m

$V_2$ = volume of diluted solution = 248 ml

$1.40\times 72.0=m\times 248$

$m=0.41M$

Now 124 mL portion of this prepared solution is diluted by adding 133 mL of water.

According to the dilution law,

$M_1V_1=M_2V_2$

where,

$M_1$ = molarity of stock solution = 0.41 M

$V_1$ = volume of stock solution = 124 ml

$M_2$ = molarity of diluted solution = m

$V_2$ = volume of diluted solution = (124 +133) ml = 257 ml

$0.41\times 124=m\times 257$

$m=0.20M$

Thus the final concentration of the solution is 0.20 M.

8 0

3 years ago