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DIA [1.3K]
2 years ago
11

A sample of rock contains 80 grams of a parent radioactive isotope that has a half-life of 20 000 years. After 100 000 years, th

e number of grams of the parent radioactive isotope remaining is
Chemistry
1 answer:
Tatiana [17]2 years ago
4 0

Answer:

2.5 g

Explanation:

Number of half lives is 100000/20000 = 5 half lives

so (1/2)^5 = 1/32 of the original sample remains

So (80)(1/32)=2.5 g

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Select ALL! the solutes below that would be soluble in a polar solvent (like water).
Fofino [41]

Answer:

K2SO4, NH3, HOCI, HCI, CH3NH2,  SiCl4, CO2, CH20

Explanation:

Substances are soluble in water when they are ionic or polar covalent substances.

If we look at the substances listed, K2SO4 is ionic while  NH3, HOCI, HCI, CH3NH2,  SiCl4, CO2, CH20 all contain polar covalent bonds which accounts for their water solubility.

Hence ionic and polar covalent substances are soluble in a polar solvent such as water.

6 0
3 years ago
What is a solute?
olya-2409 [2.1K]

Answer:

C. The substance that is dissolved in another substance

Explanation:

a solute is a substance dissolved in another substance, known as a solvent

5 0
2 years ago
At constant volume, the heat of combustion of a particular compound, compound A, is − 3039.0 kJ / mol. When 1.697 g of compound
melisa1 [442]

Answer:

13.85 kJ/°C

-14.89 kJ/g

Explanation:

<em>At constant volume, the heat of combustion of a particular compound, compound A, is − 3039.0 kJ/mol. When 1.697 g of compound A (molar mass = 101.67 g/mol) is burned in a bomb calorimeter, the temperature of the calorimeter (including its contents) rose by 3.661 °C. What is the heat capacity (calorimeter constant) of the calorimeter? </em>

<em />

The heat of combustion of A is − 3039.0 kJ/mol and its molar mass is 101.67 g/mol. The heat released by the combustion of 1.697g of A is:

1.697g.\frac{1mol}{101.67g} .\frac{(-3039.0kJ)}{mol} =-50.72kJ

According to the law of conservation of energy, the sum of the heat released by the combustion and the heat absorbed by the bomb calorimeter is zero.

Qcomb + Qcal = 0

Qcal = -Qcomb = -(-50.72 kJ) = 50.72 kJ

The heat capacity (C) of the calorimeter can be calculated using the following expression.

Qcal = C . ΔT

where,

ΔT is the change in the temperature

Qcal = C . ΔT

50.72 kJ = C . 3.661 °C

C = 13.85 kJ/°C

<em>Suppose a 3.767 g sample of a second compound, compound B, is combusted in the same calorimeter, and the temperature rises from 23.23°C to 27.28 ∘ C. What is the heat of combustion per gram of compound B?</em>

Qcomb = -Qcal = -C . ΔT = - (13.85 kJ/°C) . (27.28°C - 23.23°C) = -56.09 kJ

The heat of combustion per gram of B is:

\frac{-56.09 kJ}{3.767g} =-14.89 kJ/g

4 0
3 years ago
73.5 mol of P4O10 contains how many moles of P ? moles of P:
Sholpan [36]

Answer:

294 moles of P

Explanation:

For every 1 mol of P4O10 contains 4 mol of P

so;

73.5 mol P4O10 × <u> </u><u> </u><u> </u><u> </u><u> </u><u>4 mol P</u><u> </u><u> </u><u> </u><u> </u><u> </u>

1 mol P4O10

= 73.5 × 4

= 294 moles of P

7 0
2 years ago
How much force is needed to accelerate a 56 kg skier at 3 m/s?
Aloiza [94]

Answer:

<h2>168 N</h2>

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 56 × 3

We have the final answer as

<h3>168 N</h3>

Hope this helps you

3 0
2 years ago
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