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3 years ago

. What is the mass, in grams, of a sample of 7.83 × 1024 atoms of helium (He)?

Chemistry

1 answer:

erica [24]3 years ago

6 0

Moles He = 7.83 x 10^24 / 6.02 x 10^23 =13.0

<span>mass He = 13.0 mol x 4.00 g/mol = 52.0 g</span>

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0.0200 moles of a compound is found to have a mass of 1.64 g. Find the formula mass of the compound

KatRina [158]

Answer: 82.0 g/mole

Explanation:

Use the units to see that if we divide 1.64 grams by 0.0200 moles, we'll get a number that is grams/mole, the definition of formula mass.

1.64/0.0200 = 82.0 g/mole (3 sig figs)

We can't tell from this alone what the molecular formula might be, but C6H10 (cyclohexene) comes close (82.1 grams/mole).

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3 years ago

1.00 pint of milk has a volume of how many milliliters

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3 years ago

Exactly 1.0 mol N2O4 is placed in an empty 1.0-L container and is allowed to reach equilibriumdescribed by the equation N2O4(g)↔

Vilka [71]

Answer : The correct option is, (C) 1.1

Solution : Given,

Initial moles of $N_2O_4$ = 1.0 mole

Initial volume of solution = 1.0 L

First we have to calculate the concentration $N_2O_4$ .

$\text{Concentration of }N_2O_4=\frac{\text{Moles of }N_2O_4}{\text{Volume of solution}}$

$\text{Concentration of }N_2O_4=\frac{1.0moles}{1.0L}=1.0M$

The given equilibrium reaction is,

$N_2O_4(g)\rightleftharpoons 2NO_2(g)$

Initially c 0

At equilibrium $(c-c\alpha)$ $2c\alpha$

The expression of $K_c$ will be,

$K_c=\frac{[NO_2]^2}{[N_2O_4]}$

$K_c=\frac{(2c\alpha)^2}{(c-c\alpha)}$

where,

$\alpha$ = degree of dissociation = 40 % = 0.4

Now put all the given values in the above expression, we get:

$K_c=\frac{(2c\alpha)^2}{(c-c\alpha)}$

$K_c=\frac{(2\times 1\times 0.4)^2}{(1-1\times 0.4)}$

$K_c=1.066\aprrox 1.1$

Therefore, the value of equilibrium constant for this reaction is, 1.1

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3 years ago

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amm1812

Neutrons have no electrical charge.

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3 years ago

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andreev551 [17]

Answer:

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Explanation:

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3 years ago

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