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3 years ago

How many moles of methane are in 7.31*10^25 molecules

1 answer:

4 0

Avogadro's Constant says 1 mole of substance has 6.02214086 × 10²³ (Unit is mol⁻¹) particles.

This means, 1 mole = 6.02214086 × 10²³ molecules / atoms

Given methane molecules = 7.31 x 10²⁵
moles of methane = 7.31 x 10²⁵ / 6.02214086 × 10²³ mol⁻¹
= 121.39 mol

Hence, 7.31 x 10²⁵ of methane molecules have 121.39 moles.

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I need help with number 8 please help ASAP.

Rzqust [24]

Answer:

33.33% = 33%

Explanation:

MgCO3(s) + 2HCl (aq) --> MgCl2(aq) + H20(l) + CO2(g)

1 mole of MCO3 will produce → 1 mole of CO2

We need to get the number of mole of CO2:

and when we have 0.22 g of CO2, so number of mole = mass / molar mass

Moles = 0.22 g / 44 g/mol = 0.005 mole

Moles of Mg = moles of CO2 = 0.005 mole

Mass of Mg = moles * molar mass

= 0.005 * 84 /mol = 0.42 g

Percent of MgCO3 by mass of Mg = 0.42 g / 1.26 * 100

=33.33 %

8 0

3 years ago

Which is the formula for magnesium nitride?

Mekhanik [1.2K]

Explanation:

Mg₃N₂ is the formula of magnesium nitride.

5 0

3 years ago

Read 2 more answers

12 POINTS!!!! Consider the diagram. Which postulate of the kinetic-molecular theory best describes the event in the diagram?

podryga [215]

The separation of molecules. I wouldn't put that if i were you.

8 0

3 years ago

Read 2 more answers

Antimony has two naturally occuring isotopes, 121 Sb and 123 Sb . 121 Sb has an atomic mass of 120.9038 u , and 123 Sb has an at

valina [46]

Answer:

Percentage abundance of 121 Sb is = 57.2 %

Percentage abundance of 123 Sb is = 42.8 %

Explanation:

The formula for the calculation of the average atomic mass is:

$Average\ atomic\ mass=(\frac {\%\ of\ the\ first\ isotope}{100}\times {Mass\ of\ the\ first\ isotope})+(\frac {\%\ of\ the\ second\ isotope}{100}\times {Mass\ of\ the\ second\ isotope})$

Given that:

Since the element has only 2 isotopes, so the let the percentage of first be x and the second is 100 -x.

For first isotope, 121 Sb :

% = x %

Mass = 120.9038 u

For second isotope, 123 Sb:

% = 100 - x

Mass = 122.9042 u

Given, Average Mass = 121.7601 u

Thus,

$121.7601=\frac{x}{100}\times 120.9038+\frac{100-x}{100}\times 122.9042$

$120.9038x+122.9042\left(100-x\right)=12176.01$

Solving for x, we get that:

x = 57.2 %

<u>Thus, percentage abundance of 121 Sb is = 57.2 % </u>

<u>percentage abundance of 123 Sb is = 100 - 57.2 % = 42.8 %</u>

6 0

3 years ago

n a coffee cup calorimeter, 100.0 mL of 1.0M NaOH and 100.0 mL of 1.0M HCl are mixed. Both solutions were originally at 24.6 deg

RoseWind [281]

Answer:

Explanation:

mass of the solution = volume x density = 200 x 1 = 200 gm

heat absorbed = m x s x Δ t , s is specific heat , Δt is rise in temperature

= 200 x 4.18 x ( 31.3 - 24.6 )

= 5601 J .

This is the enthalpy change required.

3 0

3 years ago