Solve this conversion of units

A piece of charcoal is found to contain

Naddika [18.5K]

Answer: The tree died 9709.46 years before.

Explanation:

Expression for rate law for first order kinetics is given by:

$t=\frac{2.303}{k}\log\frac{a}{a-x}$

where,

k = rate constant

t = age of sample

a = let initial amount of the reactant = 100

a - x = amount left after decay process = $\frac{30}{100}\times 100=30$

a) to find rate constant

Half life is the amount of time taken by a radioactive material to decay to half of its original value.

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

$k=\frac{0.693}{5600years}=1.24\times 10^{-4}years^{-1}$

b) to know the age

$t=\frac{2.303}{1.24\times 10^{-4}}\log\frac{100}{30}$

$t=9709.46years$

The tree died 9709.46 years before.

8 0

3 years ago

Which statement best describes how the temperature of the ocean's surface water varies \

Maurinko [17]

The answer is C, high altitudes remove the water from heat source.

8 0

4 years ago

An ideal gas contained in 5.0 liter chamber at a temperature of 37°C. If

kodGreya [7K]

Answer:

i am doing this in science also i would like to know if u know

Explanation:

8 0

4 years ago

A gas is contained in a thick-walled balloon. When the pressure changes from 39.1 bar to 87.0 bar the volume changes from blank

lidiya [134]

Answer: -

1.34 L

Explanation: -

Initial Pressure P 1 = 39.1 bar

Initial Temperature T 1 = 643 K

Let the initial volume be V 1.

Final pressure P 2 = 87.0 bar

Final temperature T 2 = 525 K.

Final volume V 2 = 0.492 L

Using the equation

$\frac{P1 V 1}{T1} = \frac{P 2 V 2}{T2}$

$V 1 = \frac{P2 V2 T1}{P 1 T2}$

Plugging in the values

We have

V 1 = 87 bar x 0.492 L x 643 K / (39.1 bar x 525 K)

= 1.34 L

Thus, a gas is contained in a thick-walled balloon. When the pressure changes from 39.1 bar to 87.0 bar the volume changes from 1.34 L to 0.492L and the temperature changes from 643K to 525K

4 0

4 years ago

Read 2 more answers

How many minutes will it take to plate out 2.19 g of chromium metal from a solution of Cr3+Cr3+ using a current of 55.2 amps in

Kamila [148]

Answer : The time it take to plate out will be, 3.69 minutes.

Explanation :

First we have to calculate the moles of Cr.

$\text{Moles of }Cr}=\frac{\text{Mass of Cr}}{\text{Molar mass of Cr}}$

Molar mass of Cr = 51.9 g/mol

$\text{Moles of }Cr}=\frac{2.19g}{51.9g/mol}=0.0423mol$

The cathode half-reaction is,

$Cr^{3+}+3e^-\rightarrow Cr$

From this we conclude that,

The number of electrons (n) in the reaction are 3.

The quantity of charge required for the reduction of 1 mole of $Cr^{3+}$ = $3\times F$

The quantity of charge required for the reduction of 0.0423 mole of $Cr^{3+}$ = $0.0423\times 3\times F=0.1269F=0.1269\times 96500C=12245.85C$

Now we have to calculate the time taken.

We know that,

$q=I\times t$

$t=\frac{q}{I}=\frac{12245.85C}{55.2A}=221.845s=3.69min$

Thus, the time it take to plate out will be, 3.69 minutes.

7 0

3 years ago