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scoundrel [369]
3 years ago
11

A rock is found to contain 2.2 grams of uranium-235, a radioactive isotope. If the rock has undergone 2.75 half-lives, what was

the original amount of uranium-235 in the rock and how old is the rock
Chemistry
1 answer:
Verizon [17]3 years ago
3 0

Answer:

=14.8 grams

Explanation:

The remaining amount is normally calculated using the formula:

Remaining mass= 1/2ⁿ × Original mass where n is the number of half-lives.

Therefore, original mass= Remaining mass × 2ⁿ

Remaining mass= 2.2 grams

Number of half lives= 2.75 half lives

Original mass= 2.2g × 2²·⁷⁵

=14.8 grams

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The density of a metal is 10.5 g/cm3. If the mass of themetal
vitfil [10]

Answer:

11.7 mL

Explanation:

Density of a substance is given by the mass of the substance divided by the volume of the substance .

Hence , d = m / V

V = volume

m = mass ,  

d = density ,

From the question ,

The density of the metal = 10.5 g/cm³

The mass of the metal = 5.25 g

Hence , the volume can be calculated from the above formula , i.e. ,

d = m / V  

V = m / d

V = 5.25 g / 10.5 g/cm³

V = 0.5 cm³

Since , The unit 1 mL = 1 cm³

V = 0.5 mL

The vessel has 11.2 mL of water ,

The new volume becomes ,

11.2 mL +  0.5 mL = 11.7 mL

4 0
3 years ago
Why couldn't you substitute 3m H2SO4 for concentrated HNO3 when oxidizing copper?
schepotkina [342]

This question seems to be an essay question from experiment. Different solution of oxidizing agent will have different strength.  Sulfuric acid or H2SO4 is weaker oxidizing agent when compared to nitric acid (HNO3). In this case, if you subtitute the H2SO4 you wouldn't be able to get the same result for the experiment.



5 0
4 years ago
Read 2 more answers
Why does the atmosphere have holes in it? A. Pollution B. Fuel from Cars/Machines
a_sh-v [17]

Answer:

the answer is d .

Explanation:

all of these have pollutants and chemicals in them , damaging the ozone with carbon dioxide .

7 0
3 years ago
A solution is prepared by dissolving 0.23 mol of hypochlorous acid and 0.27 mol of sodium hypochlorite in water sufficient to yi
finlep [7]

Answer:

hypochlorite ion

Explanation:

The hypochlorous acid, HClO, is a weak acid with Ka = 1.36x10⁻³, when this acid is in solution with its conjugate base, ClO⁻ (From sodium hypochlorite, NaClO) a buffer is produced. When a strong acid as HCl is added, the reaction that occurs is:

HCl + ClO⁻ → HClO + Cl⁻.

Where more hypochlorous acid is produced.

That means, the HCl reacts with the hypochlorite ion present in solution

3 0
3 years ago
What is the molarity of 5.63 moles of lithium in 3.25 liters of solution
luda_lava [24]

Answer:

1.73 Molar

Explanation:

The formula is Molarity=moles of solute/liters of solution, which can be written in whatever way you prefer, and examples include: M=N/V or M=mol/L.

M=N/V

M= \frac{5.63}{3.25}

Divide 5.63 by 3.25. When you calculate this, you get 1.73, therefore your answer is 1.73 molar.

5 0
3 years ago
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