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3 years ago

Mole-Atom Conversions

Chemistry

1 answer:

iragen [17]3 years ago

7 0

Answer:

Explanation:

1) How many moles are 1.55 × 10²⁷ atoms of zinc?

Answer:

0.26 × 10⁴ mole

Explanation:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For 1.55 × 10²⁷ atoms of zinc:

1.55 × 10²⁷ atoms × 1 mole/ 6.022 × 10²³ atoms

0.26 × 10⁴ mole

2) How many atoms are in 25.0 moles of calcium?

Answer:

150.55 × 10²³ atoms.

Explanation:

According to Avogadro number,

one mole of substance = 6.022 × 10²³ atoms

The number 6.022 × 10²³ is called Avogadro number.

For 25.0 moles of calcium:

one mole of calcium = 6.022 × 10²³ atoms

25.0 mole × 6.022 × 10²³ atoms /1 mole

150.55 × 10²³ atoms.

So 25.0 moles of calcium contain 150.55 × 10²³ atoms.

3) = How many atoms are in 0.35 moles of carbon?

Answer:

2.12× 10²³ atoms.

Explanation:

According to Avogadro number,

one mole of substance = 6.022 × 10²³ atoms

The number 6.022 × 10²³ is called Avogadro number.

For 0.35 moles of carbon:

one mole of carbon = 6.022 × 10²³ atoms

0.35 mole × 6.022 × 10²³ atoms /1 mole

2.12× 10²³ atoms.

So 0.35 moles of carbon contain 2.12× 10²³ atoms.

4 ) How many moles are 7.6 × 10²⁴ atoms of hellium?

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

For example,

18 g of water = 1 mole = 6.022 × 10²³ molecules of water

1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen

For 7.6 × 10²⁴ atoms of hellium:

7.6 × 10²⁴ atoms × 1 mole/ 6.022 × 10²³ atoms

12. 6 mole

Mass - Mole conversion:

How many moles in 28.0 gram of oxygen?

Answer:

1.75 mol

Explanation:

Given data:

Mass of oxygen = 28 g

Number of moles = ?

Solution:

Formula:

Number of moles = mass/ molar mass

Molar mass of oxygen = 16 g/mol

Now we will put the values in formula:

Number of moles = 28 g / 16 g/mol

Number of moles = 1.75 mol

So 28 g of oxygen contain 1.75 moles.

3) Find the number of moles of argon in 452 g?

Answer:

11.31 mol

Explanation:

Given data:

Mass of argon = 452 g

Number of moles = ?

Solution:

Formula:

Number of moles = mass/ molar mass

Molar mass of argon= 39.95 g/mol

Now we will put the values in formula:

Number of moles = 452 g /39.95 g/mol

Number of moles = 11.31 mol

So 452 g of argon contain 11.31 moles.

2) What is the mass of 5.0 moles of iron?

Answer:

Mass = 279.25 g

Explanation:

Given data:

Mass of iron = ?

Number of moles of iron = 5.0 mol

Solution:

Formula:

Mass = number of moles × molar mass

Molar mass of iron = 55.85 g/mol

Now we will put the values in formula:

Mass = number of moles × molar mass

Mass = 5 mol × 55.85 g/mol

Mass = 279.25 g

4) Find the grams of 16.5 mole of hydrogen?

Answer:

Mass = 16.632 g

Explanation:

Given data:

Mass of hydrogen = ?

Number of moles of hydrogen = 16.5 mol

Solution:

Formula:

Mass = number of moles × molar mass

Molar mass of hydrogen = 1.008 g/mol

Now we will put the values in formula:

Mass = number of moles × molar mass

Mass = 16.5 × 1.008 g/mol

Mass = 16.632 g

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Scrat [10]

Explanation:

When a plate moves it shifts the earth, and it can cause an earthquake.

A fault is where two of earth's tectonic plates come together. They can slide against the other, causing earthquakes, they can push against each other causing mountains to form, and they can move apart from each other, causing valleys or trenches.

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A 50.0-mL volume of 0.15 M HBr is titrated with 0.25 M KOH. Calculate the pH after the addition of 13.0 mL of KOH. Express your

Mazyrski [523]

Answer:

pH= 1.17

Explanation:

The neutralization reaction between HBr (acid) and KOH (base) is given by the following equation:

HBr(aq) + KOH(aq) → KBr(aq) + H₂O(l)

According to this equation, 1 mol of HBr reacts with 1 mol of KOH. Then, the moles can be expressed as the product between the molarity of the acid/base solution (M) and the volume in liters (V). So, we calculate the moles of acid and base:

Acid:

M(HBr) = 0.15 M = 0.15 mol/L

V(HBr) = 50.0 mL x 1 L/1000 mL = 0.05 L

moles of HBr = M(HBr) x V(HBr) = 0.15 mol/L x 0.05 L = 7.5 x 10⁻³ moles HBr

Base:

M(KOH) = 0.25 M = 0.25 mol/L

V(HBr) = 13.0 mL x 1 L/1000 mL = 0.013 L

moles of HBr = M(HBr) x V(HBr) = 0.25 mol/L x 0.013 L = 3.25 x 10⁻³ moles KOH

Now, we have: 7.5 x 10⁻³ moles HBr > 3.25 x 10⁻³ moles KOH

HBr is a strong acid and KOH is a strong base, so they are completely dissociated in water: the acid produces H⁺ ions and the base produces OH⁻ ions. So, the difference between the moles of HBr and the moles of KOH is equal to the moles of remaining H⁺ ions after neutralization:

moles of H⁺ = 7.5 x 10⁻³ moles HBr - 3.25 x 10⁻³ moles KOH = 4.25 x 10⁻³ moles H⁺

From the definition of pH:

pH = -log [H⁺]

The concentration of H⁺ ions is calculated from the moles of H⁺ divided into the total volume:

total volume = V(HBr) + V(KOH) = 0.05 L + 0.013 L = 0.063 L

[H⁺] = (moles of H⁺)/(total volume) = 4.25 x 10⁻³ moles/0.063 L = 0.067 M

Finally, we calculate the pH after neutralization:

pH = -log [H⁺] = -log (0.067) = 1.17

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Semenov [28]

All chemical reactions have a conversation of mass and energy.

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3 years ago

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Balance this redox reaction occurring in acidic media:

Lelu [443]

Add 7 water atom to the right hand side to adjust the quantity of oxygen. Increase Cr(+3) by two to adjust the quantity of Cr. Duplicate Cl-by two to adjust the quantity of chlorine molecules.
Cr2O7[2-](aq) +2 Cl[-](aq) < - >2 Cr[3+] (aq) + Cl2(g)+7H2O
Presently adjust that charges.
you have - 4 charges on the left hand side, while +18 charges on the right hand side, there for include 14H+ the left hand side to adjust the charges
Cr2O7[2-](aq) +2 Cl[-](aq)+14H+ < - >2 Cr[3+] (aq) + Cl2(g)+7H2O
take note of that the oxidation number of hydrogen in water is +1

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2 years ago

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Igoryamba

Answer:

The arm that was not sprayed with anything

Explanation:

The control group would be the arm that was not sprayed with anything.

The control group during an experiment is a group that forms the baseline for comparison in other to determine the effects of a treatment. The control group does not include the variable that is being tested and as such, it provides the benchmark to measure the effects of the tested variable on the other group - the experimental group. In this case, the experimental group would be the arm that was sprayed with the repellent.

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