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3 years ago

What is the difference between physical and chemical changes?

1 answer:

4 0

In physical changes, the chemical makeup of an atom stays the same, like water turning into ice or steam, everything is still water but a different physical form. A chemical change is where an atom’s chemical make up does change, like wood burning to become soot, which is not wood, or photosynthesis, where carbon dioxide and water turn into a carbohydrate and oxygen

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What is the mass of the solid NH4Cl formed when 75.5 g of NH3 is mixed with an equal mass of HCl? What is the volume of the gas

Gekata [30.6K]

Answer : The volume of the gas remaining is 56.5 liters.

The gas is hydrochloric acid and the formula of the gas is HCl.

The mass of $NH_4Cl$ produced is, 110.7 grams.

Explanation :

The balanced chemical reaction will be:

$NH_3+HCl\rightarrow NH_4Cl$

First we have to calculate the moles of $NH_3$ and HCl

$\text{Moles of }NH_3=\frac{\text{Mass of }NH_3}{\text{Molar mass of }NH_3}$

Molar mass of NH_3 = 17 g/mole

$\text{Moles of }NH_3=\frac{75.5g}{17g/mole}=4.44mole$

and,

$\text{Moles of }HCl=\frac{\text{Mass of }HCl}{\text{Molar mass of }HCl}$

Molar mass of HCl = 36.5 g/mole

$\text{Moles of }HCl=\frac{75.5g}{36.5g/mole}=2.07mole$

Now we have to calculate the limiting and excess reagent.

From the balanced reaction we conclude that

As, 1 mole of HCl react with 1 mole of $NH_3$

So, 2.07 mole of HCl react with 2.07 mole of $NH_3$

From this we conclude that, $NH_3$ is an excess reagent because the given moles are greater than the required moles and HCl is a limiting reagent and it limits the formation of product.

The remaining moles of HCl gas = 4.44 - 2.07 = 2.37 moles

Now we have to calculate the volume of the gas remaining.

Using ideal gas equation :

PV = nRT

where,

P = Pressure of gas = 752 mmHg = 0.989 atm (1 atm = 760 mmHg)

V = Volume of gas = ?

n = number of moles of gas = 2.37 moles

R = Gas constant = 0.0821 L.atm/mol.K

T = Temperature of gas = $14.0^oC=273+14.0=287K$

Putting values in above equation, we get:

$0.989atm\times V=2.37mole\times (0.0821L.atm/mol.K)\times 287K$

V = 56.5 L

Now we have to calculate the moles of $NH_4Cl$

As, 1 mole of HCl react with 1 mole of $NH_4Cl$

So, 2.07 mole of HCl react with 2.07 mole of $NH_4Cl$

Now we have to calculate the mass of $NH_4Cl$

$\text{ Mass of }NH_4Cl=\text{ Moles of }NH_4Cl\times \text{ Molar mass of }NH_4Cl$

Molar mass of $NH_4Cl$ = 53.5 g/mole

$\text{ Mass of }NH_4Cl=(2.07moles)\times (53.5g/mole)=110.7g$

Thus, the volume of the gas remaining is 56.5 liters.

The gas is hydrochloric acid and the formula of the gas is HCl.

The mass of $NH_4Cl$ produced is, 110.7 grams.

3 0

2 years ago

How many phases are in a homogeneous mixture??

Mars2501 [29]

Technically there is only one phase unless you account for a solution where you have a pure liquid with something dissolved in it. Unless you count aqueous as a phase which is just dissolved. Since you are in high school the answer you are looking for is one. <span />

7 0

3 years ago

Read 2 more answers

Which statement is correct about molarity and volume?

Oksana_A [137]

Answer:

Explanation:

If the choices are:

A. Molarity is defined as moles of solute per liter of solvent.

B. % by mass is defined as grams of solute per 100 g of solvent.

C. % by volume is defined as grams of solute per 100 L of solution.

D. Molarity is defined as moles of solute per liter of solution.

E. All of the above.

then the ans is E

7 0

3 years ago

Under ordinary conditions of temperature and pressure, the particles in a gas are

vova2212 [387]

<span>In normal conditions gas particles remain very distant from each other. They rarely collide and are stable. When temperature increases the gas particles begin to move faster and collide more, reducing the distance. When pressure increases the gas particles also pick up kinetic speed and are also closer to each other.</span>

4 0

3 years ago

Tell how you could distinguish between the pair of compounds by their infrared spectra: compound a ch3ch2ch2n(ch3)2 and compound

maksim [4K]

Answer:-

b. compound b will show an nh absorption while compound a will not.

Explanation:-

For compound B CH3CH2CH2NH2 there are two N-H bonds present. So it will show NH absorption.

But in compound A CH3CH2CH2N(CH3)2 there are no N-H bonds. So it will not show NH absorption.

6 0

3 years ago