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1 year ago

The graph shows a sample of gas when it is hot, cold, and at room temperature.

Chemistry

1 answer:

AveGali [126]1 year ago

3 0

Answer:

B represents gas at room temperature and C represents hot gas.

Explanation:

As the temperature increases, the no. of particles that has higher energy increases.

So, A represents the cold gas, because it has the lowest no. of particles that has high energy.

B represents the gas at room T because it has more no. of particles with higher energy.

C represents the hot gas, because it is the curve that has the highest no. of particles with high energy.

So, the right choice is:

B represents gas at room temperature and C represents hot gas.

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Of the concentration units below, only ________ uses kg of solvent in its calculation.

oksano4ka [1.4K]

Answer:

E) molality

Explanation:

Molality -

Molarity of a substance , is the number of moles present in a Kg of solvent .

Hence , the formula for molality is given as follow -

m = n / s

m = molality

s = mass of solvent in Kg ,

n = moles of solute ,

Hence , from the given information of the question,

The concentration unit which have Kg of solvent , is molality.

6 0

2 years ago

What volume (mL) of a 0.3428 M HCl(aq) solution is required to completely neutralize 23.55 mL of a 0.2350 M Ba(OH)2(aq) solution

EastWind [94]

Answer:

The volume required for complete neutralize is 32.29 mL

Explanation:

The computation of the volume required for complete neutralize is shown below:

As we know that, the balanced equation is

$Ba(OH)_2 + 2Hcl\rightarrow Bacl_2 + 2H_2O$

Now

The number of moles of $Ba(OH)_2$ = n_1 = 1

And, the number of moles of Hcl = n_2 = 2

Therefore

The equation i.e. to be used to find out the volume is given below:

$\frac{M_1V_1}{n_1} = \frac{M_2V_2}{n_2}$

$V_2 = \frac{M_1V_1}{n_1} \times \frac{n_2}{M_2} \\\\ = \frac{0.2350 \times 23.55}{1} \times \frac{2}{0.3428} \\\\ = \frac{11.0685}{0.3428}$

= 32.29 mL

Hence, the volume is 32.29mL

6 0

2 years ago

When a 21.5-g sample of LiCl was added to 195 g of water at a temperature of 20.00°C in a calorimeter, the temperature increased

Paha777 [63]

Answer:

$63.09KJ/mol$

Explanation:

In this case, to calculate the heat of solution (KJ/mol) we have to take into account the mass of water, the specific heat of the water and the temperature change, so:

$m=195~g$

$c=4.18~J/g^{\circ}C$

Δ $T=39.26^{\circ}C$

With this in mind, we can use the equation:

$Q=m*c*T$

If we plug the values into the equation we will have:

$Q=195~g*4.18~J/g^{\circ}C*39.26^{\circ}C$

$Q=32000.83~J$

Now, with the mass value (21.5 g) and the molar mass of LiCl (42.39g/mol) we can calculate the moles of LiCl:

$21.5~g~LiCl\frac{1~mol~LiCl}{42.39~g~LiCl}=0.507~mol~LiCl$

Now, in the heat of solution, we have KJ/mol units. Therefore, we have to convert from J to KJ:

$32000.83~J\frac{1~KJ}{1000~J}=32~KJ$

Finally, we can divide by the moles of LiCl:

$\frac{32~KJ}{0.507~mol}=63.09KJ/mol$

So, for each mole of LiCl, we have 63.09 KJ involved in the dissolution process.

I hope it helps!

8 0

2 years ago

Determine the unknown mineral using the information given below. Be sure to use significant figure rules when doing calculations

Mademuasel [1]

Answer:

Mass: 981.0 g

Density: 5.61 g/cm^3

Hardness: = 2.5 - 3

Unknown material: Chalcocite

8 0

1 year ago

penicillin. an important antibiotic (antibacterial agent), was discovered accidentally by the scottish bacteriologist alexander

dmitriy555 [2]

Answer:

mass percent of carbon = 57.78 %

mass percent of hydrogen = 6.40 %

mass percent of nitrogen = 8.96 %

mass percent of oxygen = 20.49 %

mass percent of sulfur = 10.24 %

Explanation:

Given data

Molecular formula = C₁₄H₂₀N₂O₄S

molecular mass (total mass) = 312.39 g/mol

Percentage of carbon = ?

Percentage of hydrogen = ?

Percentage of oxygen = ?

Percentage of nitrogen = ?

Percentage of sulfur = ?

Solution

1st we find out number of moles of each element from the molecular formula

Number of moles of carbon = 14 mol

Number of moles of hydrogen = 20 mol

Number of moles of nitrogen = 2 mol

Number of moles of oxygen = 4 mol

Number of moles of sulfur = 1 mol

Now we find out the mass of each element

as we know that

mass = number of moles × molecular mass

mass of carbon = 14 mol × 12 g/mol

mass of carbon = 168 g

mass of hydrogen = 20 mol × 1 g/mol

mass of hydrogen = 20 g

mass of nitrogen = 2 mol × 14 g/mol

mass of nitrogen = 28 g

mass of oxygen = 4 mol × 16 g/mol

mass of oxygen = 64 g

mass of sulfur = 1 mol × 32 g/mol

mass of sulfur = 32 g

now we find out the mass percent of each element

mass percent = ( mass ÷ total mass ) × 100

mass percent of carbon = ( 168 g ÷ 312.39 g/mol ) × 100

mass percent of carbon = 57.78 %

mass percent of hydrogen = ( 20 g ÷ 312.39 g/mol ) × 100

mass percent of hydrogen = 6.40 %

mass percent of nitrogen = ( 28 g ÷ 312.39 g/mol ) × 100

mass percent of nitrogen = 8.96 %

mass of oxygen =( 64 g ÷ 312.39 g/mol ) × 100

mass percent of oxygen = 20.49 %

mass percent of sulfur = ( 32 g ÷ 312.39 g/mol ) × 100

mass percent of sulfur = 10.24 %

7 0

2 years ago