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3 years ago

Where do fossils live

Chemistry

2 answers:

Elan Coil [88]3 years ago

6 0

Answer:

Fossils are often found in rock formations deep in the earth.

Explanation:

It would be greatly appreciated if you gave me the brainlest

Paraphin [41]3 years ago

4 0

Fossils are often found in rock formations in the deep earth

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Purification of copper can be achieved by electrorefining copper from an impure copper anode onto a pure copper cathode in an el

Dovator [93]

Answer: 406 hours

Explanation:

$Q=I\times t$

where Q= quantity of electricity in coloumbs

I = current in amperes = 39.5 A

t= time in seconds = ?

The deposition of copper at cathode is represented by:

$Cu^{2+}+2e^-\rightarrow Cu$

$96500\times 2=193000$ Coloumb of electricity deposits 1 mole of copper

i.e. 63.5 g of copper is deposited by = 193000 Coloumb

Thus 19.0 kg or 19000 g of copper is deposited by = $\frac{193000}{63.5}\times 19000=57748032$ Coloumb

$57748032=39.5\times t$

$t=1461975sec=406hours$ (1hour=3600s)

Thus it will take 406 hours to plate 19.0 kg of copper onto the cathode if the current passed through the cell is held constant at 39.5 A

3 0

3 years ago

How many grams will be produced

Anni [7]

Answer:

$\Large \boxed{\sf 34.2 \ g}$

Explanation:

Mole ratio

$9:4$

$1.75:x$

Moles of CO₂

$\displaystyle \frac{4 \times 1.75}{9} =0.78$

Use formula to find mass

$\displaystyle moles=\frac{mass}{M_r}$

Relative molecular mass of CO₂ = 12 + 16 × 2 = 44

$\displaystyle 0.78=\frac{mass}{44}$

$mass=34.2$

4 0

2 years ago

Which of the following will increase entropy in a reaction?

Lapatulllka [165]

B. Heating up the reaction will increase the entropy of a reaction.

<h3>What is entropy?</h3>

Entropy is the measure of the degree of disorderliness of a system.

Entropy is also the measure of a system's thermal energy per unit temperature that is unavailable for doing useful work.

S = ΔH/T

where;

S is entropy
ΔH is energy input
T is temperature

Entropy increases in reactions in which the total number of product molecules is greater than the total number of reactant molecules.

However, entropy increases as temperature increases. Thus, heating up the reaction will increase the entropy of a reaction.

Learn more about entropy here: brainly.com/question/6364271

#SPJ1

3 0

2 years ago

Thorium-234 has a half-life of 24.1 days. How many grams of a 150 g sample would you have after 120.5 days?

chubhunter [2.5K]

Answer:

8.625 grams of a 150 g sample of Thorium-234 would be left after 120.5 days

Explanation:

The nuclear half life represents the time taken for the initial amount of sample to reduce into half of its mass.

We have given that the half life of thorium-234 is 24.1 days. Then it takes 24.1 days for a Thorium-234 sample to reduced to half of its initial amount.

Initial amount of Thorium-234 available as per the question is 150 grams

So now we start with 150 grams of Thorium-234

$150 \times \frac{1}{2}=24.1$

$75 \times \frac{1}{2} =48.2$

$34.5 \times \frac{1}{2} =72.3$

$17.25 \times \frac{1}{2} =96.4$

$8.625\times \frac{1}{2} =120.5$

So after 120.5 days the amount of sample that remains is 8.625g

In simpler way , we can use the below formula to find the sample left

$A=A_{0} \cdot \frac{1}{2^{n}}$

Where

$A_0$ is the initial sample amount

n = the number of half-lives that pass in a given period of time.

7 0

3 years ago

In aqueous solution, hypobromite ion, BrO-, reacts to produce bromate ion, BrO3 -, and bromide ion, Br-, according to the follow

maw [93]

Answer:

22.73s

Explanation:

The reaction is a second order reaction, we know this by observing the unit of the slope.

rate constant = k = 0.056 M-1s-1

the initial concentration of BrO- [A]o = 0.80 M

time = ?

Final concentration [A]t= one-half of 0.80 M = 0.40M

1 / [A]t = kt + 1 / [A]o

1 / 0.40 = 0.056 * t + 1 / 0.80

t = (2.5 - 1.25) / 0.056

t = 22.73s

5 0

3 years ago