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3 years ago

If an atom of an element has a mass number of 45 and it has 20 neutrons in its nucleus, what is the atomic number of the

Chemistry

1 answer:

HACTEHA [7]3 years ago

3 0

Answer:

Explanation:

uestion

If an atom of an element has a mass number of 45 and it has 20 neutrons in its nucleus, what is the atomic number of the

element?

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Which statement describes an atomic nucleus?

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Construct an argument for or against the immediate introduction of fuel-cell cars. Include likely points of objection from those

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Answer:

Explanation:

Fuel Cell Cars are the vehicles built to run on hydrogen gas rather than running on the hydrocarbon.

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3 years ago

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If the mass of the baking soda before the reaction was 10 grams and the mass of the vinegar was 15 grams and all of the baking s

Masteriza [31]

Answer:

8.946g NaHCO₃,

14.475g H₂O,

1.025g CH₃COO⁻Na⁺,

0.500g CO₂.

Explanation:

Baking soda (NaHCO₃) reacts with vinegar (CH₃COOH 5%) producing CH₃COO⁻Na⁺, H₂O and CO₂, thus:

NaHCO₃ + CH₃COOH → CH₃COO⁻Na⁺ + H₂O + CO₂

10g of NaHCO₃ are:

10g × (1mol / 84g) = 0.119 moles NaHCO₃

Moles of CH₃COOH in 15g of vinegar are:

15g vinegar × 5% = 0.75g CH₃COOH × (1mol / 60g) = 0.0125moles CH₃ COOH

After reaction, moles of NaHCO₃ that remains are:

0.119mol - 0.0125mol = 0.1065 moles NaHCO₃

In mass:

0.1065mol ₓ (84g / 1mol) = 8.946g NaHCO₃

Acetic acid reacts completely producing 0.0125moles of CH₃COO⁻Na⁺, water and CO₂. In mass:

CH₃COO⁻Na⁺ = 0.0125mol ₓ (82.03g / 1mol) = 1.025g CH₃COO⁻Na⁺

H₂O = 0.0125mol ₓ (18.01g / 1mol) = 0.225g H₂O

CO₂ = 0.0125mol ₓ (40g / 1mol) = 0.500g CO₂

Now, 95% of vinegar is water (Doesn't react), that is:

15g × 95% = 14.25g H₂O. Total mass of water is:

14.25g + 0.225g = 14.475g H₂O

Total mass is:

8.946g + 14.475g H₂O + 1.025g + 0.500g ≈ 25g. The same than initial mass following law of conservation of matter.

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3 years ago