How old is the idea that matter is composed of atoms?

How many moles are present in 356.4 g of NiBr3

lozanna [386]

1.194 mol

(remember to use sig figs!)

8 0

3 years ago

Given 4.80g of ammonium carbonate, find:

V125BC [204]

Answer:

1) 0.05 mol.

2) 0.1 mol.

3) 0.05 mol.

4) 0.4 mol.

5) 2.4 x 10²³ molecules.

Explanation:

1) Number of moles of the compound:

no. of moles of ammonium carbonate = mass/molar mass = (4.80 g)/(96.09 g/mol) = 0.05 mol.

2) Number of moles of ammonium ions :

Ammonium carbonate is dissociated according to the balanced equation:

(NH₄)₂CO₃ → 2NH₄⁺ + CO₃²⁻.

It is clear that every 1.0 mole of (NH₄)₂CO₃ is dissociated to produce 2.0 moles of NH₄⁺ ions and 1.0 mole of CO₃²⁻ ions.

∴ The no. of moles of NH₄⁺ ions in 0.05 mol of (NH₄)₂CO₃ = (2.0)(0.05 mol) = 0.1 mol.

3) Number of moles of carbonate ions :

Ammonium carbonate is dissociated according to the balanced equation:

(NH₄)₂CO₃ → 2NH₄⁺ + CO₃²⁻.

It is clear that every 1.0 mole of (NH₄)₂CO₃ is dissociated to produce 2.0 moles of NH₄⁺ ions and 1.0 mole of CO₃²⁻ ions.

∴ The no. of moles of CO₃²⁻ ions in 0.05 mol of (NH₄)₂CO₃ = (1.0)(0.05 mol) = 0.05 mol.

4) Number of moles of hydrogen atoms:

Every 1.0 mol of (NH₄)₂CO₃ contains:

2.0 moles of N atoms, 8.0 moles of H atoms, 1.0 mole of C atoms, and 3.0 moles of O atoms.

∴ The no. of moles of H atoms in 0.05 mol of (NH₄)₂CO₃ = (8.0)(0.05 mol) = 0.4 mol.

5) Number of hydrogen atoms:

It is known that every mole of a molecule or element contains Avogadro's number (6.022 x 10²³) of molecules or atoms.

Using cross multiplication:

1.0 mole of H atoms contains → 6.022 x 10²³ atoms.

0.4 mole of H atoms contains → ??? atoms.

∴ The no. of atoms in 0.4 mol of H atoms = (6.022 x 10²³ molecules)(0.4 mole)/(1.0 mole) = 2.4 x 10²³ molecules.

8 0

3 years ago

If a question cannot be tested and observed, it cannot be answered with science. (2 points) True or False?

boyakko [2]

Answer:

True

Explanation:

If a question cannot be tested and observed, it cannot simply be answered by science.

Science works with observable and testable ideas and not on metaphysics.

Science presents a methodical approach into investigating phenomenon and answering likely questions in a logical manner.
The body of facts and data gathered through observations and tests are used to ramify the conclusion of a scientific study.
Without such, it is impossible to do the work of science.

3 0

3 years ago

For alpha decay to cause a loss in mass, such as that in the uranium 238 conversion to thorium 234, what must the atomic weight

Aleonysh [2.5K]

Explanation:

Reaction equation showing alpha decay in Uranium-238 is as follows.

$^{238}_{92}U \rightarrow ^{234}_{90}Th + ^{4}_{2}He$

It is known that an alpha particle is basically a helium nucleus and it contains 2 protons and 2 neutrons.

Symbol of an alpha particle is $^{4}_{2}\alpha$ .

As atomic mass or weight is the sum of total number of protons and neutrons present in an atom.

Hence, the atomic weight of the alpha particle is (2 + 2) = 4.

6 0

3 years ago

Based on the activity series of metal, which reaction with water will not happen?

laila [671]

Answer:

B

Explanation:

B, H2O + Na The elements toward the bottom left corner of the periodic table are the metals that are the most active in the sense of being the most reactive. Lithium, sodium, and potassium all react with water,

5 0

3 years ago