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4 years ago

Dose the weight of a human change

Chemistry

1 answer:

prisoha [69]4 years ago

4 0

Answer:

It changes as they grow

Or when they start to have an unhealthy diet

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When a 0.235-g sample of benzoic acid is combusted in a bomb calorimeter, the temperature rises 1.643 ∘C . When a 0.275-g sample

andrew-mc [135]

Answer : The heat of combustion per mole of caffeine at constant volume is 76197.18 kJ/mole

Explanation :

First we have to calculate the specific heat calorimeter.

Formula used :

$Q=m\times c\times \Delta T$

where,

Q = heat of combustion of benzoic acid = 26.38 kJ/g = 26380 J/g

m = mass of benzoic acid = 0.235 g

c = specific heat of calorimeter = ?

$\Delta T$ = change in temperature = $1.643^oC$

Now put all the given value in the above formula, we get:

$26380J/g=0.235g\times c\times 1.643^oC$

$c=68323.38J/^oC$

Thus, the specific heat of calorimeter is $68323.38J/^oC$

Now we have to calculate the heat of combustion of caffeine.

Formula used :

$Q=c\times \Delta T$

where,

Q = heat of combustion of caffeine = ?

c = specific heat of calorimeter = $68323.38J/^oC$

$\Delta T$ = change in temperature = $1.584^oC$

Now put all the given value in the above formula, we get:

$Q=68323.38J/^oC\times 1.584^oC$

$Q=108224.23J=108.2kJ$

Now we have to calculate the moles of caffeine.

$\text{Moles of caffeine}=\frac{\text{Mass of caffeine}}{\text{Molar mass of caffeine}}$

Mass of caffeine = 0.275 g

Molar mass of caffeine = 194.19 g/mole

$\text{Moles of caffeine}=\frac{0.275g}{194.19g/mole}=0.00142mol$

Now we have to calculate the heat of combustion per mole of caffeine at constant volume.

$\text{Heat of combustion per mole of caffeine}=\frac{108.2kJ}{0.00142mol}=76197.18kJ/mole$

Therefore, the heat of combustion per mole of caffeine at constant volume is 76197.18 kJ/mole

4 0

3 years ago

Express the following in regular notation:

dusya [7]

A because if you multiple it, you will be moving the decimal one time

8 0

4 years ago

Does not react with aqueous solution of bromine (a)C2H6 (b)C2H4 (c)C2H2 (d)C3H6

Damm [24]

Answer:

Hi, there!

which does not react with aqueous solution of bromine?

c)C2H2

xXxAnimexXx

Happy Labor day! :)

3 0

3 years ago

What is the molar mass of a covalent compound if 0.486 g of it is dissolved in 25.0 ml of water and produces a freezing temperat

Semmy [17]

Answer is: the molar mass of a covalent compound is 90.4 g/mol.

m(compound) = 0.486 g.
m(water) = 25 mL · 1 g/mL = 25 g ÷ 1000 g/kg = 0.025 kg.
ΔT = 0°C - (-0.40°C) = 0.40°C.

Kf(H₂O) = 1.86°C/m.

M(compound) = Kf · m(compound) / m(water) · ΔT.
M(compound)= 1.86°C/m · 0.486 g / (0.025 kg · 0.4°C).
M(compound) = 90.4 g/mol.

3 0

4 years ago

How many grams of sodium iodide, nai, must be used to produce 97.1 g of iodine, i2?

Aliun [14]

Iodine is prepared both in the laboratory and commercially by adding Cl2(g) to an aqueous solution containing sodium iodide: 2NaI(aq) + Cl2(g) ---> I2(s) + 2NaCl(aq) (97.1 g I2) / (253.8089 g I2/mol) x (2 mol NaI / 1 mol I2) x (149.8942 g NaI/mol) = 12.7 g NaI.

8 0

3 years ago