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3 years ago

A radioactive isotope has a half-life of 10 years. What fraction of the original mass will remain unchanged after 50 years

Chemistry

1 answer:

Fofino [41]3 years ago

6 0

The fraction is calculated like this:

$\frac{1}{ {2}^{50 \div 10} } = \frac{1}{32}$

If you want an universal equation for all problems like this:

$\frac{1}{ {2}^{time \div halflife} }$

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On combustion, 1.0 L of a gaseous compound of hydrogen, carbon, and sulfur gives 2.0 L of CO2, 3.0 L of H2O vapor, and 1.0 L of

Murrr4er [49]

Answer:

The empirical formula of the organic compound is = $C_2H_6S_1$

Explanation:

At STP, 1 mole of gas occupies 22.4 L of volume.

Moles of $CO_2$ gas at STP occupying 2.0 L = n

$n\times 22.4L=2.0L$

$n=\frac{2.0 L}{22.4 L}=0.08929 mol$

Moles of carbon in 0.08920 mol = 1 × 0.08920 mol = 0.08920 mol

Moles of $H_2O$ gas at STP occupying 3.0 L = n'

$n'\times 22.4L=3.0L$

$n'=\frac{3.0 L}{22.4 L}=0.1339 mol$

Moles of hydrogen in 0.1339 moles of water vapor = 2 × 0.1339 mol = 0.2678 mol

Moles of $SO_2$ gas at STP occupying 1.0 L = n''

$n''\times 22.4L=1.0L$

$n''=\frac{1.0 L}{22.4 L}=0.04464 mol$

Moles of sulfur in 0.04464 mol = 1 × 0.04464 mol = 0.04464 mol

Moles of carbon , hydrogen and sulfur constituent of that organic compound .

Moles of carbon in 0.08920 mol = 1 × 0.08920 mol = 0.08920 mol

Moles of hydrogen in 0.1339 moles of water vapor = 2 × 0.1339 mol = 0.2678 mol

Moles of sulfur in 0.04464 mol = 1 × 0.04464 mol = 0.04464 mol

For empirical; formula divide the least number of moles from all the moles of elements.

carbon = $\frac{0.08920 mol}{0.04464 mol}=2$

Hydrogen = $\frac{0.2678 mol}{0.04464 mol}=6$

Sulfur = $\frac{0.04464 mol}{0.04464 mol}=1$

The empirical formula of the organic compound is = $C_2H_6S_1$

3 0

3 years ago

If 50. 75 g of a gas occupies 10. 0 l at stp, 129. 3 g of the gas will occupy ________ l at stp.

NeX [460]

22.4L

of any gas contains 1 mol of that gas.

50.75g/10L*22.4L/1 mol= 113.68g/mol- this is the mole weight of your gas

1 mol/113.68g*129.3g=1.137403 mol

Set up a ratio

1.137403mol/x L=1 mol/22.4 L

X=25.477827L, or with sig figs, x=25.5L

8 0

2 years ago

An oxygen atom has a mass of 2.66 x 10^-23 g and a glass of water has a mass of 0.050kg. Use this information to answer the ques

fomenos

<h2>ANSWER OF EACH PART ARE GIVEN BELOW</h2>

Explanation:

We know, each mole contains $N_A=$ $6.023 \times 10^{23}$ atoms.

It is given that mass of one oxygen atom is m= $2.66\times 10^{-23}\ g$ .

Therefore, mass of one mole of oxygen, $M=m\times N_A$ .

Putting value of n and $N_A$ ,

$M=2.66\times 10^{-23}\times 6.023\times 10^{23} \ gm\\M=16.0\ gm$

Given,

Mass of water in glass=0.050 kg = 50 gm.

From above part mass of one mole of oxygen atoms = 16.0 gm.

Therefore, number of mole of oxygen equivalent to 50 gm oxygen $=\dfrac{50}{16}=3.1 \ moles.$

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Avogadro's number

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3 0

3 years ago

What are some factors that affect weather?

Zarrin [17]

B is the right answer

6 0

3 years ago

What is the best conclusion according to the energy diagram of the chemical reaction?

Mariulka [41]

"The reaction will absorb energy" is the best conclusion according to the energy diagram of the chemical reaction.

<u>Option: B</u>

<u>Explanation:</u>

The chemical bonds in the reactions are broken and formed as per process and contributed by three major steps: reactants, transition phase and product formation. Here transition phase is in equilibrium stage drived by activation energy, where bond is partially formed and partially broken, located at higher energy level then the starters.

The reactant's energy level is less relative to the products as seen in the endothermic reactions' energy diagram, which depicts that the products are less balanced than reactants. Here when the reaction is forced to the forward direction, then it direct towards the more unbalance entities. As energy is absorbed in the endothermic reaction from surrounding, thus the enthalpy change (ΔH) for the reaction is positive.

5 0

4 years ago