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3 years ago

How many atoms are in 0.75 moles of CH4?

Chemistry

1 answer:

Anastasy [175]3 years ago

6 0

Answer:

Explanation:

Thus, if we have 6.022 × 10 23 O atoms, we say we have 1 mol of O atoms. If we have 2 mol of Na atoms, we have 2 × (6.022 × 10 23) Na atoms, or 1.2044 × 10 24 Na atoms. Similarly, if we have 0.5 mol of benzene (C 6H 6) molecules, we have 0.5 × (6.022 × 10 23) C 6H 6 molecules, or 3.011 × 10 23 C 6H 6 molecules.

For example the atomic mass of methane (CH4)is 12 amu for the carbon plus 4 x 1 amu for the four hydrogens, for a total of 16 amu. Therefore the molar mass of methane is 16g. We say that one mole of methane has a mass of 16 g, and that there are 6.022 x 1023 atoms in that mass of methane.

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Oil is more dense than water. How will this affect the weight of objects that will float on it?

horrorfan [7]

Oil is more dense than alcohol, but less dense than water. The molecules that make up the oil are larger than those that that make up water, so they cannot pack as tightly together as the water molecules can. They take up more space per unit area and are less dense.

3 0

3 years ago

If 5.65 grams of zinc metal react with 21.6 grams of silver nitrate, how many grams of silver metal can be formed and how many g

Igoryamba

The balanced chemical reaction is:

Zn + 2AgNO3 = Zn(NO3)2 + 2Ag

To determine the amount of the reactant left, we have to determine which is the limiting and the excess reactant. We do as follows:

5.65 g Zn ( 1 mol / 65.38 g) = 0.09 mol Zn
21.6 g AgNO3 (1 mol / 169.87 g) = 0.13 mol AgNO3

The limiting reactant would be silver nitrate since it is consumed completely in the reaction. The excess reactant would be zinc.

Excess Zinc = 0.09 mol Zn - (0.13 / 2) mol Zn = 0.025 mol Zn left

7 0

4 years ago

Read 2 more answers

A jet flies over the ocean. A sound wave travels from the jet to the surface of the ocean. Almost none of the energy from the so

lutik1710 [3]

We need to see the diagram

6 0

4 years ago

How do you balance the equation in number one?

AleksAgata [21]

____NaNO3 + ___PbO --> ___Pb(NO3)2 + ___Na[2]O

To balace the eqaution, you need to have the same number of atoms for each element on both the reactant (left) and product (right) side.

To start off, you wanna know the number of atoms in each element on both sides, so take it apart:

[reactants] [product]
Na- 1 Na- 2

N- 1 N- 2(it's 2 because the the subscript [2] is outside of the parenthesis)

O- 4 O- 7 (same reason as above)

Pb- 1 Pb- 1

Na is not balanced out, so add a coefficient to make it the same on both sides.In this case, multiply by 2:

2NaNO3

Now Na is balanced, but the N and O are also effected by this, so they also have to be multiplied by 2 and they become:

Na- 2 Na- 2

N- 2 N- 2 (it balanced out)

O- 7 (coefficient times subscript, plus lone O) O- 7 (balanced out)

Pb was already balanced so no need to mess with it, just put a 1 where needed (it doesn't change anything).

Now to put it back together, it will look like this:

2NaNO3 + 1PbO --> 1Pb(NO3)2 + 1Na[2]O

3 0

3 years ago

For the reaction: CH3NH2(aq) + H2O(aq) ⇌ CH3NH3 +(aq) + OH- Determine the change in the pH (ΔpH) for the addition of 6.7 M CH3NH

Korolek [52]

Answer:

The change in the pH (ΔpH) is 2,17

Explanation:

The reaction:

CH₃NH₂(aq) + H₂O(aq) ⇌ CH₃NH₃⁺(aq) + OH⁻

$kb = \frac{[OH^{-}][CH_{3}NH_{3}^+]}{[CH_{3}NH_{2}]}$ (1)

In equilibrium, a solution of CH₃NH₂ 4,7M produces:

[CH₃NH₂] = 4,7 - x

[CH₃NH₃⁺] = x

[OH⁻] = x

Replacing in (1):

$4,38x10^{-4} = \frac{x^2}{4,7-x}$

x² + 4,38x10⁻⁴x - 2,0586x10⁻³ = 0

The solutions are:

x = -0,0456 No physical sense. There are not negative concentrations.

x = 0,04515 Real answer.

The concentration of [OH⁻] is 0,04515 M.

As pOH = -log [OH⁻] And pH+pOH = 14. The pH of this solution is:

pH = 12,65

The addition of 6,7M produce this changes in concentrations:

[CH₃NH₂] = 4,656 + x

[CH₃NH₃⁺] = 6,74515 - x

[OH⁻] = 0,04515 - x

Replacing in (1) you will obtain:

x² - 6,7907x + 0,3025 = 0

Solving for x:

x = 6,74586 No physical sense

x = 0,04484 Real answer.

Thus, [OH⁻] = 0,04515 - 0,044842 = 3,08x10⁻⁴M

pOH = 3,51.

pH = 10,49

Thus ΔpH is 12,65 - 10,49 = 2,16 ≈ 2,17

I hope it helps!

4 0

4 years ago