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olga55 [171]
2 years ago
8

How many half-lives are required for the concentration of reactant to decrease to 12. 5% of its original value?.

Chemistry
1 answer:
Tcecarenko [31]2 years ago
5 0

Answer:

Three half-lives

Explanation:

12.5% is one-eighth. One eighth is the cube of one half, so it would take three half-lives to reduce a reactant's concentration to 12.5%

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Carbon-14 (14C) dating assumes that the carbon dioxide on the Earth today has the same radioactive content as it did centuries a
Nataly [62]

<u>Answer:</u> The tree was burned 16846.4 years ago to make the ancient charcoal

<u>Explanation:</u>

The equation used to calculate rate constant from given half life for first order kinetics:

t_{1/2}=\frac{0.693}{k}

where,

t_{1/2} = half life of the reaction = 5715 years

Putting values in above equation, we get:

k=\frac{0.693}{5715yrs}=1.21\times 10^{-4}yrs^{-1}

Rate law expression for first order kinetics is given by the equation:

k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}

where,

k = rate constant  = 1.21\times 10^{-4}yr^{-1}

t = time taken for decay process = ? yr

[A_o] = initial amount of the sample = 100 grams

[A] = amount left after decay process =  13 grams

Putting values in above equation, we get:

1.21\times 10^{-4}=\frac{2.303}{t}\log\frac{100}{13}\\\\t=16864.4yrs

Hence, the tree was burned 16846.4 years ago to make the ancient charcoal

8 0
2 years ago
Suppose that the mechanism of hydrolysis of tert- butyl chloride preceded by a different mechanism so that the predicted rate la
ddd [48]

Answer:

B, because that was the answer on quizlet.

Explanation:

5 0
2 years ago
Calculate the gravitational force of attraction between a 26kg boy and his 5.1kg dog when they are separated by 0.19m
Pavel [41]

Answer:

Gravitational force of attraction G(f) = 2.44 x 10⁻⁷ (approx.)

Explanation:

Given:

Mass M1 = 26 kg

Mass M2 = 5.1 kg

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Gravitational force of attraction G(f)

Computation:

Gravitational force of attraction G(f) = G(m1)(m2)/r²

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Gravitational force of attraction G(f) = 2.44 x 10⁻⁷ (approx.)

6 0
3 years ago
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Gekata [30.6K]

Answer:

None  

Explanation:

Cl₂ is above Br₂ in the activity series.

Bromine will not displace chlorine from its salts.

The reaction will not occur.

8 0
2 years ago
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How is milk souring a chemical change?
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Because the chemicals are different
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