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3 years ago

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Uranium-238 had a half life of 4.5 billion years. A 100 g sample of U-238 has decayed until only 25 g remain. How long did it ta

ke for the sample to decay? (Write the answer in “n billion years”)

1 answer:

Natasha2012 [34]3 years ago

6 0

awnseris chemical hhhh Explanation:

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Which equation agrees with the ideal gas law? mc005-1.jpg mc005-2.jpg mc005-3.jpg mc005-4.jpg

AlexFokin [52]

The ideal gas equation is pV = nRT

From that you can derive several equations, depending on which variables are fixed.

1) When n and T are fixed:

pV = nRT = constant

pV = constant => p1 V1 = p2 V2 => p1 / V2 = p2 / V1 ---> Boyle's Law

2) When n and V are constant:

p / T = nR/V = constant

p / T = constant => p1 / T1 = p2 / T2 ----> Gay - Lussac's Law

3) when n and p are constant

V / T = nR/p = constant

V / T = constant => V1 / T1 = V2 / T2 ---> Charles' Law

4) When only n is constant

pV / T = nR = constant

pV / T = constant => p1 V1 / T1 = p2 V2 / T2 ----> Combined gas law.

There you have the four equations that agree with the ideal gas law.

7 0

3 years ago

Read 2 more answers

Which conclusion was drawn from the results of

torisob [31]

Answer;

-(2) An atom is mostly empty space.

Experiment

-Rutherford conducted the "gold foil" experiment where he shot alpha particles at a thin sheet of gold. The conclusion that can be drawn from these experiment is that an atom is mostly empty space.

-Rutherford found that a small percentage of the particles were deflected, while a majority passed through the sheet. This caused Rutherford to conclude that the mass of an atom was concentrated at its center, as the tiny, dense nucleus was causing the deflections.

3 0

3 years ago

Now that Snape and Dumbledore has taught you the finer points of hydration calculations they have a slightly more challenging pr

Mrrafil [7]

Answer:

The value of an integer x in the hydrate is 10.

Explanation:

$Molarity=\frac{Moles}{Volume(L)}$

Molarity of the solution = 0.0366 M

Volume of the solution = 5.00 L

Moles of hydrated sodium carbonate = n

$0.0366 M=\frac{n}{5.00 L}$

$n=0.0366 M\times 5 mol=0.183 mol$

Mass of hydrated sodium carbonate = n= 52.2 g

Molar mass of hydrated sodium carbonate = 106 g/mol+x18 g/mol

$n=\frac{\text{mass of Compound}}{\text{molar mass of compound}}$

$0.183 mol=\frac{52.2 g}{106 g/mol+x\times 18 g/mol}$

$106 g/mol+x\times 18 g/mol=\frac{52.2 g}{0.183 mol}$

Solving for x, we get:

x = 9.95 ≈ 10

The value of an integer x in the hydrate is 10.

6 0

3 years ago

Calculate the heat required to convert 5.0 g of ice at 0.0 c to steam at 100

Fiesta28 [93]

Heat= latent heat of fusion+sensible heat+ latent heat of vapourization
=(79.7*5)+(5*100*1)+(540*5)
=3598.5 cal

6 0

4 years ago

The iodine "clock reaction" involves the following sequence of reactions occurring in a reaction mixture in a single beaker. 1.

Mars2501 [29]

C: 0.012 mol.

<h3>Explanation</h3>

Start with 0.0020 moles of iodate ions ${\text{IO}_{3}}^{-}$ .

How many moles of iodine $\text{I}_2$ will be produced?

${\text{IO}_{3}}^{-}$ converts to $\text{I}_2$ in the first reaction. The coefficient in front of $\text{I}_2$ is three times the coefficient in front of ${\text{IO}_{3}}^{-}$ . In other words, each mole of ${\text{IO}_{3}}^{-}$ will produce three moles of $\text{I}_2$ . 0.0020 moles of ${\text{IO}_{3}}^{-}$ will convert to 0.0060 moles of $\text{I}_2$ .

How many moles of thiosulfate ions ${\text{S}_2\text{O}_3}^{2-}$ are required?

$\text{I}_2$ reacts with ${\text{S}_2\text{O}_3}^{2-}$ in the second reaction. The coefficient in front of $\text{I}_2$ is twice the coefficient in front of ${\text{S}_2\text{O}_3}^{2-}$ . How many moles of ${\text{S}_2\text{O}_3}^{2-}$ does each mole of $\text{I}_2$ consume? Two. 0.0060 moles of $\text{I}_2$ will be produced. As a result, $2 \times 0.0060 = 0.0120$ moles of ${\text{S}_2\text{O}_3}^{2-}$ will be needed.

6 0

3 years ago