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Arada [10]
3 years ago
12

Astatine -211 has half a life of seven hours. If u start with 50.0 grams of astatine-211, how much will remain after 28 hours

Chemistry
1 answer:
xeze [42]3 years ago
4 0

Answer:

3.125 grams

Explanation:

Applying,

R = (2^{t/n})R'............... Equation 1

Where R = Original mass of Astatine-211, R' = mass of Astatine-211 left after decay, t = total disintegeration time, n = halflife of Astatine-211

make R' the subject of the equation

R' = R/(2^{t/n})............ Equation 2

From the question,

Given: R = 50 grams, t = 28 hours, n = 7 hours

Substitute into equation 2

R' = 50/(2^{28/7})

R' = 50/(2⁴)

R' = 50/16

R' = 3.125 grams

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klasskru [66]

Answer:

a = 0.57 m/s²

Explanation:

Given data:

Mass = 70 kg

Force = 40 N

Acceleration = ?

Solution:

Definition:

The acceleration is rate of change of velocity of an object with respect to time.

Formula:

a = Δv/Δt

a = acceleration

Δv = change in velocity

Δt = change in time

Units:

The unit of acceleration is m.s⁻².

Acceleration can also be determine through following formula,

F = m × a

a = F/m

Now we will put the values in formula.

a = 40 N / 70 Kg

a = 40 Kg. m/s² / 70 Kg

a = 0.57 m/s²

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