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3 years ago

Radioactivity in our world _____.

1 answer:

4 0

Radioactivity in our world <span>b. is as old as the universe.
</span><span>Radioactive atom spontaneously emits energetic particles or waves, while decays on lighter nuclei (atoms with smaller atomic mass). Radioactivity is used to calculate how old is Earth and living things, for that purpose isotope of carbon is used.</span>

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A sample of gas occupies 280 mL when the pressure is 560.00 mm Hg . If the temperature remains constant , what is the new pressu

vichka [17]

Answer : The new pressure if the volume changes to 560.0 mL is, 280 mmHg

Explanation :

According to the Boyle's, law, the pressure of the gas is inversely proportional to the volume of gas at constant temperature and moles of gas.

$P\propto \frac{1}{V}$

or,

$P_1V_1=P_2V_2$

where,

$P_1$ = initial pressure = 560.00 mmHg

$P_2$ = final pressure = ?

$V_1$ = initial volume = 280 mL

$V_2$ = final volume = 560.0 mL

Now put all the given values in the above formula, we get:

$560.00mmHg\times 280 mL=P_2\times 560.0 mL$

$P_2=280mmHg$

Therefore, the new pressure if the volume changes to 560.0 mL is, 280 mmHg

3 0

3 years ago

1. Calculate the RFM of Fe(NO3)2

miss Akunina [59]

Answer:

The Relative Formula Mass of Fe(NO₃)₂ is 179.8524 grams

Explanation:

The Relative Formula Mass is the mass of one mole of a compound expressed in grams, obtained by adding together the Relative Atomic Masses, RAM, of the elements which makes the compound

The Relative Formula Mass of a compound is the same as its Relative Molecular Mass

The relative formula mass of Fe(NO₃)₂ is given as follows;

The relative atomic mass of Fe = 55.845 amu

The relative atomic mass of nitrogen, N = 14.0067 amu

The relative atomic mass of oxygen, O = 15.999 amu

Therefore, we have;

The formula mass of Fe(NO₃)₂ = (55.845 + 2×(14.0067 + 3×15.999)) amu = 179.8524 amu

The Relative Formula Mass of Fe(NO₃)₂ = 179.8524 grams.

5 0

3 years ago

A gas used to extinguish fires is composed of 75 % CO2 and 25 % N2. It is stored in a 5 m3 tank at 300 kPa and 25 °C. What is th

tatyana61 [14]

Answer : The partial pressure of the $CO_2$ in the tank in psia is, 32.6 psia.

Explanation :

As we are given 75 % $CO_2$ and 25 % $N_2$ in terms of volume.

First we have to calculate the moles of $CO_2$ and $N_2$ .

$\text{Moles of }CO_2=\frac{\text{Volume of }CO_2}{\text{Volume at STP}}=\frac{75}{22.4}=3.35mole$

$\text{Moles of }N_2=\frac{\text{Volume of }N_2}{\text{Volume at STP}}=\frac{25}{22.4}=1.12mole$

Now we have to calculate the mole fraction of $CO_2$ .

$\text{Mole fraction of }CO_2=\frac{\text{Moles of }CO_2}{\text{Moles of }CO_2+\text{Moles of }N_2}$

$\text{Mole fraction of }CO_2=\frac{3.35}{3.35+1.12}=0.75$

Now we have to calculate the partial pressure of the $CO_2$ gas.

$\text{Partial pressure of }CO_2=\text{Mole fraction of }CO_2\times \text{Total pressure of gas}$

$\text{Partial pressure of }CO_2=0.75mole\times 300Kpa=225Kpa=225Kpa\times \frac{0.145\text{ psia}}{1Kpa}=32.625\text{ psia}$

conversion used : (1 Kpa = 0.145 psia)

Therefore, the partial pressure of the $CO_2$ in the tank in psia is, 32.6 psia.

3 0

3 years ago

Help pleassssse match allllll of them...

sleet_krkn [62]

Look at the letters, 3 would be MMeters

4 0

3 years ago

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A teacher makes the following statement.

melamori03 [73]

The correct answer among the choices given is the first option.The teacher most likely is talking about distillation of a mixture. Distillation is a unit operation that separates component substances from a liquid mixture which is shown by the teacher. Also, the most common purifying technique in the production of gasoline is by this process.

5 0

3 years ago

Read 2 more answers