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3 years ago

Pls help me I don’t know what to dooooo

Chemistry

1 answer:

Ivan3 years ago

5 0

Molarity = moles of solute/volume of solution in liters.

The solute here is NaCl, of which we have 46.5 g. To calculate the molarity of an NaCl solution, we need to know the number of moles of NaCl. To convert from grams to moles, we divide the mass by the molar mass of NaCl. The molar mass of NaCl is the sum of the atomic masses of Na and Cl: 23 amu + 35 amu = 58 amu. For our purposes, we can regard amu as equivalent to grams/mole.

(46.5 g)/(58 g/mol) = 0.8017 moles NaCl.

Now that we know both the number of moles of our NaCl solute and the volume of the solution, we can calculate the molarity:

(0.8017 moles NaCl)/(2.2 L) = 0.364 M.

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The molecular structure of water contains two atoms of hydrogen and one atom of oxygen. When water reaches its boiling point and

nikklg [1K]

The water reaches its boiling point and turns into water vapor. This process is a physical change. The change is substance status. And the physical change will not destroy the molecular structure. So the molecular structure will not change.

7 0

3 years ago

If 150 g dimethylhydrazine reacts with excess dinitrogen tetroxide and the product gases are collected at 127oC in an evacuated

zhuklara [117]

Answer : The the partial pressure of the nitrogen gas is 0.981 atm.

The total pressure in the tank is 2.94 atm.

Explanation :

The balanced chemical reaction will be:

$(CH_3)_2N_2H_2(l)+2N_4O_4(l)\rightarrow 3N_2(g)+4H_2O(g)+2CO_2(g)$

First we have to calculate the moles of dimethylhydrazine.

Mass of dimethylhydrazine = 150 g

Molar mass of dimethylhydrazine =60.104 g/mole

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

$\text{Moles of dimethylhydrazine}=\frac{150g}{60.104g/mole}=2.49mole$

Now we have to calculate the moles of $N_2$ gas.

From the balanced chemical reaction we conclude that,

As, 1 mole of $(CH_3)_2N_2H_2$ react to give 3 moles of $N_2$ gas

So, 2.49 mole of $(CH_3)_2N_2H_2$ react to give $2.49\times 3=7.47$ moles of $N_2$ gas

Now we have to calculate the partial pressure of nitrogen gas.

Using ideal gas equation :

$PV=nRT\\\\P_{N_2}=\frac{nRT}{V}$

where,

P = Pressure of $N_2$ gas = ?

V = Volume of $N_2$ gas = 250 L

n = number of moles $N_2$ gas = 7.47 mole

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

T = Temperature of $N_2$ gas = $127^oC=273+127=400K$

Putting values in above equation, we get:

$P_{N_2}=\frac{(7.47mole)\times (0.0821L.atm/mol.K)\times 400K}{250L}=0.981atm$

Thus, the partial pressure of the nitrogen gas is 0.981 atm.

Now we have to calculate the total pressure in the tank.

Formula used :

$P_{N_2}=X_{N_2}\times P_T$

$P_T=\frac{1}{X_{N_2}}\times P_{N_2}$

$P_T=\frac{1}{(\frac{n_{N_2}}{n_T})}\times P_{N_2}$

$P_T=\frac{n_{T}}{n_{N_2}}\times P_{N_2}$

where,

$P_T$ = total pressure = ?

$P_{N_2}$ = partial pressure of nitrogen gas = 0.981 atm

$n_{N_2}$ = moles of nitrogen gas = 3 mole (from the reaction)

$n_{T}$ = total moles of gas = (3+4+2) = 9 mole (from the reaction)

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

$P_T=\frac{9mole}{3mole}\times 0.981atm=2.94atm$

Thus, the total pressure in the tank is 2.94 atm.

8 0

3 years ago

Water is a substance made up of the elements hydrogen

xeze [42]

Answer:

A. 2

Explanation:

A particle of water is made up of two hydrogen atoms and one oxygen atom. However, the question asked for how many types of atoms there are, so the answer is 2.

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3 years ago

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Can someone please help me with this chemistry hw plzzzzz I really need help

Viktor [21]

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Which element has a partially filled f orbital? sm os ba bi

Sladkaya [172]

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i hope i helped :)