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3 years ago

2) what is the mass of 6.02 x 1023 atoms of arsenic?

1 answer:

6 0

Data:
Arsenic Molar Mass = 74,9216 ≈ 75 u (<span>atomic mass unit)</span>

Solving:

1 mole of arsenic → 75g ------------ 6,02*10²³ molecules
..................................X -------------- 1 molecule

6,02*10²³X = 75
$x = \frac{75}{6,02*10^{23}}$
$\boxed{x \approx 1,24*10^{24}grams}$

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Given the unbalanced equation: Al + O2 → Al2O3

ArbitrLikvidat [17]

I believe it's 1. 9.

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What is the temperature of CO2 gas if the average speed (actually the root-mean-square speed) of the molecules is 750 m/s?

erastova [34]

Answer:

992.302 K

Explanation:

V(rms) = 750 m/s

V(rms) = √(3RT / M)

V = velocity of the gas

R = ideal gas constant = 8.314 J/mol.K

T = temperature of the gas

M = molar mass of the gas

Molar mass of CO₂ = [12 + (16*2)] = 12+32 = 44g/mol

Molar mass = 0.044kg/mol

From

½ M*V² = 3 / 2 RT

MV² = 3RT

K = constant

V² = 3RT / M

V = √(3RT / M)

So, from V = √(3RT / M)

V² = 3RT / M

V² * M = 3RT

T = (V² * M) / 3R

T = (750² * 0.044) / 3 * 8.314

T = 24750000 / 24.942

T = 992.302K

The temperature of the gas is 992.302K

Note : molar mass of the gas was converted from g/mol to kg/mol so the value can change depending on whichever one you use.

3 0

3 years ago

Wood with a mass of 3.0 grams was burned in an open dish. The ashes weighed 1.2 grams.

mr_godi [17]

The rest of the wood was burned into gases of equivalent weight.

<u>Explanation</u>:

The rest of the wood was burned into gases of equivalent weight.

When wood is burnt in the open air, with the help of oxygen and heat, it is transformed into carbon dioxide, water vapor, and ashes.

Ignition and combustion of wood mainly depend on pyrolysis which is also known as thermal combustion.

The loss in weight of the ashes is due to the fact that gases and water vapor are also formed due to the combustion of wood.

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How do we detect the change in energy?

IrinaVladis [17]

It’s properties unless we can look at the pattern in which it changes matter.
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2 years ago

A compound contains 78.14% B and 21.86% H by mass and has a molar mass of 27.67 g/mol. What is the molecular formula of the comp

ziro4ka [17]

Answer:

The molecular formula of the compound is B₂H₆

Explanation:

From the question given above, the following data were obtained:

Composition of Boron (B) = 78.14%

Composition of Hydrogen (H) = 21.86%

Molar mass of compound = 27.67 g/mol

Molecular formula =?

Next, we shall determine the empirical formula of the compound. This can be obtained as follow:

B = 78.14%

H = 21.86%

Divide by their molar mass

B = 78.14 / 11 = 7.104

H = 21.86 / 1 = 21.86

Divide by the smallest

B = 7.104 / 7.104 = 1

H = 21.86 / 7.104 = 3

Thus, the empirical formula of the compound is BH₃

Finally, we shall determine the molecular formula of the compound. This can be obtained as illustrated below:

Molecular formula = empirical formula × n

Molecular formula = [BH₃]ₙ

Thus, we shall determine the value of n to obtain the molecular formula. The value of n can be obtained as follow:

[BH₃]ₙ = 27.67

[11 + (3×1)]n = 27.67

[11 + 3]n = 27.67

14n = 27.67

Divide both side by 14

n = 27.67 / 14

n = 2

Molecular formula = [BH₃]ₙ

Molecular formula = [BH₃]₂

Molecular formula = B₂H₆

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3 years ago