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3 years ago

Why does half a mole of water molecules have more mass than 2 moles of helium atoms?

Chemistry

2 answers:

Fantom [35]3 years ago

6 0

Answer:

everything (matter) is made up of molecules(atoms)

Explanation:

RUDIKE [14]3 years ago

5 0

Answer:

Mass H2O = 9.01 grams

Mass He = 8.0 grams

The mass per mol of water is more than the mass per mol of helium.

Explanation:

Step 1: Data given

Molar mass water = 18.02 g/mol

Molar mass of helium = 4.0 g/mol

Number of moles H2O = 0.5 moles

Number of moles He = 2.0 moles

Step 2: Calculate mass

Mass = moles * molar mass

Mass H2O = 0.5 moles * 18.02 g/mol

Mass H2O = 9.01 grams

Mass He = 2.0 moles * 4.0 g/mol

Mass He = 8.0 grams

The mass per mol of water is more than the mass per mol of helium.

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The overall charge of an atom is ________ if the number of electrons is ________ than the number of protons.

miss Akunina [59]

The overall charge of an atom is positive if the number of electrons is less than the number of protons. Electrons are negatively charged particles while protons are positively charged particles. If there are less electrons as compared to the number of protons in an atom, then naturally the overall charge of the atom would be positive since there are excess protons. Another case would be that the overall charge of an atom is negative if the number of electrons is greater than the number of protons. An atom having more electrons than the number of the protons present would lead to a negative value of the charge since there are excess electrons.

8 0

3 years ago

When 9.2 g of frozen N2O4 is added to a 0.50 L reaction vessel and the vessel is heated to 400 K and allowed to come to equilibr

Amanda [17]

Answer: The value of $K_c$ for the given reaction is 1.435

Explanation:

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Mass of solute}}{\text{Molar mass of solute}\times \text{Volume of solution (in L)}}$

Given mass of $N_2O_4$ = 9.2 g

Molar mass of $N_2O_4$ = 92 g/mol

Volume of solution = 0.50 L

Putting values in above equation, we get:

$\text{Molarity of solution}=\frac{9.2g}{92g/mol\times 0.50L}\\\\\text{Molarity of solution}=0.20M$

For the given chemical equation:

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

Initial: 0.20

At eqllm: 0.20-x 2x

We are given:

Equilibrium concentration of $N_2O_4$ = 0.057

Evaluating the value of 'x'

$\Rightarrow (0.20-x)=0.057\\\\\Rightarrow x=0.143$

The expression of $K_c$ for above equation follows:

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

$[NO_2]_{eq}=2x=(2\times 0.143)=0.286M$

$[N_2O_4]_{eq}=0.057M$

Putting values in above expression, we get:

$K_c=\frac{(0.286)^2}{0.143}\\\\K_c=1.435$

Hence, the value of $K_c$ for the given reaction is 1.435

6 0

3 years ago

A pharmaceutical company states in advertisements that their new ScarX Cream is guaranteed to erase scars in one month.

SOVA2 [1]

Answer:d

Explanation:

the results indicated

7 0

3 years ago

Which Of the following compounds is an electrolyte?

Anettt [7]

Hello,

Here is your answer:

The proper answer to this question is option D "sodium hydroxide".

Here is how:

Sodium Hydroxide its a white substance that is a electrolyte.

Your answer is D.

If you need anymore help feel free to ask me!

Hope this helps!

8 0

3 years ago

What is the new concentration of 25.0mL added to 125.0mL of 0.150M

____ [38]

Answer:

The new concentration is 0.125 M.

Explanation:

Given data:

Initial volume V₁ = 125.0 mL

Initial molarity M₁ = 0.150 M

New volume V₂ = 25 mL +125 mL = 150 mL

New concentration M₂ = ?

Solution:

M₁V₁ = M₂V₂

0.150 M × 125 mL = M₂ × 150 mL

M₂ = 0.150 M × 125 mL / 150mL

M₂ = 18.75 M.mL/150 mL

M₂ = 0.125 M

The new concentration is 0.125 M.

8 0

3 years ago