What determines which element an atom is ?

A gas has a volume of 300 mL in a rigid container at 50oC and 1.75 atm. What will be its pressure at 100K?

eduard

Answer:

Its pressure will be 0.54 atm at 100 K.

Explanation:

Gay-Lussac's law indicates that, as long as the volume of the container containing the gas is constant, as the temperature increases, the gas molecules move faster. Then the number of collisions with the walls increases, that is, the pressure increases. That is, the pressure of the gas is directly proportional to its temperature.

Gay-Lussac's law can be expressed mathematically as the quotient between pressure and temperature equal to a constant:

$\frac{P}{T} =k$

Studying two different states, an initial state 1 and a final state 2, it is satisfied:

$\frac{P1}{T1} =\frac{P2}{T2}$

In this case:

P1= 1.75 atm
T1= 50 °C= 323 K (being 0 C=273 K)
P2= ?
T2= 100 K

Replacing:

$\frac{1.75 atm}{323 K} =\frac{P2}{100 K}$

Solving:

$P2= 100 k*\frac{1.75 atm}{323 K}$

P2= 0.54 atm

Its pressure will be 0.54 atm at 100 K.

8 0

3 years ago

How many milliliters of 2.19 M H2SO4 are required to react with 4.75 g of solid containing 21.6 wt% Ba(NO3)2 if the reaction is

Setler [38]

Answer:

1.7927 mL

Explanation:

The mass of solid taken = 4.75 g

This solid contains 21.6 wt% $Ba(NO_3)_2$ , thus,

Mass of $Ba(NO_3)_2$ = $\frac {21.6}{100}\times 4.75\ g$ = 1.026 g

Molar mass of $Ba(NO_3)_2$ = 261.337 g/mol

The formula for the calculation of moles is shown below:

$moles = \frac{Mass\ taken}{Molar\ mass}$

Thus,

$Moles= \frac{1.026\ g}{261.337\ g/mol}$

$Moles= 0.003926\ mol$

Considering the reaction as:

$Ba(NO_3)_2+H_2SO_4\rightarrow BaSO_4+2HNO_3$

1 moles of $Ba(NO_3)_2$ react with 1 mole of $H_2SO_4$

Thus,

0.003926 mole of $Ba(NO_3)_2$ react with 0.003926 mole of $H_2SO_4$

Moles of $H_2SO_4$ = 0.003926 mole

Also, considering:

$Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}$

Molarity = 2.19 M

So,

$2.19=\frac{0.003926}{Volume\ of\ the\ solution(L)}$

Volume = 0.0017927 L

Also, 1 L = 1000 mL

So, volume = 1.7927 mL

5 0

3 years ago

How many grams of Cl, will be produced by the electrolysis of 23.4 g NaCl?

VLD [36.1K]

Answer:

Explanation:

You know that

2

Na

(

s

)

+

Cl

2

(

g

)

→

2

NaCl

(

s

)

and that the reaction produced

234 g

of sodium chloride. Convert this to moles by using the compound's molar mass

234

g

⋅

1 mole NaCl

58.44

g

=

4.004 moles NaCl

Now, you know that the sample of sodium metal reacted completely, which implies that it was completely consumed by the reaction.

In other words, you don't have to worry about the sample of chlorine gas because the fact that sample of sodium metal was completely consumed lets you know that the chlorine gas is not a limiting reagent.

This means that the reaction consumed

4.004

moles NaCl

⋅

2 moles Na

2

moles NaCl

=

4.004 moles Na

Convert this to grams by using the element's molar mass

4.004

moles Na

⋅

22.99 g

1

mole Na

=

92.1 g

−−−−−

The answer is rounded to three sig figs.

SIDE NOTE You can show that chlorine gas is not the limiting reagent by calculating the number of moles present in the sample

0.142

kg

⋅

1 mole Cl

2

35.453

kg

=

4.005 moles Cl

2

In order to produce

4.004

moles of sodium chloride, you only need

4.004

moles NaCl

⋅

1 mole Cl

2

moles NaCl

=

2.002 moles Cl

2

Since you have more chlorine gas than you need, chlorine is in excess.vExplanation:

You know that

2

Na

(

s

)

+

Cl

2

(

g

)

→

2

NaCl

(

s

)

and that the reaction produced

234 g

of sodium chloride. Convert this to moles by using the compound's molar mass

234

g

⋅

1 mole NaCl

58.44

g

=

4.004 moles NaCl

Now, you know that the sample of sodium metal reacted completely, which implies that it was completely consumed by the reaction.

In other words, you don't have to worry about the sample of chlorine gas because the fact that sample of sodium metal was completely consumed lets you know that the chlorine gas is not a limiting reagent.

This means that the reaction consumed

4.004

moles NaCl

⋅

2 moles Na

2

moles NaCl

=

4.004 moles Na

Convert this to grams by using the element's molar mass

4.004

moles Na

⋅

22.99 g

1

mole Na

=

92.1 g

−−−−−

The answer is rounded to three sig figs.

SIDE NOTE You can show that chlorine gas is not the limiting reagent by calculating the number of moles present in the sample

0.142

kg

⋅

1 mole Cl

2

35.453

kg

=

4.005 moles Cl

2

In order to produce

4.004

moles of sodium chloride, you only need

4.004

moles NaCl

⋅

1 mole Cl

2

moles NaCl

=

2.002 moles Cl

2

Since you have more chlorine gas than you need, chlorine is in excess.

Explanation:

8 0

3 years ago

Ethanol is added to gasoline to produce E-15 and E-85. It promotes more complete combustion of the gasoline and is an octane boo

Artist 52 [7]

Answer:

2,2,4-trimethylpentane has the higher heat of combustion in kcal/mol.

Explanation:

Heat of combustion is defined as heat evolved on combustion of 1 mole of a substance.

2,2,4-trimethylpentane has the higher heat of combustion in kcal/mol.

Heat combustion of 2,2,4-trimethylpentane = (1304 kcal/mol) and

$C_8H_{18}+\frac{25}{2}O_2\rightarrow 8CO_2+9H_2O,\Delta H=-1,304 kcal/mol$

1 mole of 2,2,4-trimethylpentane on combustion gives 8 mole sof carbon dioxide gas and 9 moles of water.

Heat combustion of ethanol = (327 kcal/mol)

$C_2H_5OH+3O_2\rightarrow 2CO_2+3H_2O,\Delta H=-327kcal/mol$

1 mole of ethanol on combustion gives 2 moles of carbon dioxide gas and 3 mole of water.

Heat combustion of ethanol < Heat combustion of 2,2,4-trimethylpentane

7 0

3 years ago

When balancing a chemical equation:

PolarNik [594]

Answer: There must be the same number of atoms of each element on both sides of the equation.

Explanation: This is the only way the equations will be balanced. Adding the coefficients to see if they are equal will not guarantee that the equations are balanced becuase coefficients can be turned into subscripts.

3 0

4 years ago