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k0ka [10]
3 years ago
15

Calculate the number of molecules present in 3.50 mol FeO2.

Chemistry
2 answers:
Gwar [14]3 years ago
8 0
3.5*(6.02*10^23)=2.107*10^24 molecules, so A
Reika [66]3 years ago
5 0
If you do 3.50 x 6.022x10^23 it will equal 2.1077e+24which you will then round to 2.11e+23
so the answer is 2.11e+23
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A chemist combined 0.440 L of an unknown calcium solution with an excess of ammonium chromate. This resulted in the precipitatio
Rina8888 [55]

The concentration of the original calcium ions is 0.005 M

<h3>What is concentration?</h3>

The term concentration has to do with the amount of substance in solution. We know that the concentration can be measured in a lot of units such as mole/litre, grams per litre, percentage and so on.

As such we have the equation;

Ca^2+(aq) + (NH4)2CrO4(aq) --------> CaCrO4(s) + 2NH4^+(aq)

Number of moles of the precipitate = 346.7 * 10^-3 g/156 g/mol

= 0.0022 moles

Now;

1 mole of Ca^2+ produces 1 mole of CaCrO4 hence 0.0022 moles of CaCrO4 was produced by  0.0022 moles of CaCrO4.

Given that the volume of the solution is  0.440 L, the concentration of the solution is;   0.0022 moles/0.440 L

= 0.005 M

Learn more about molarity:brainly.com/question/8732513

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6 0
1 year ago
. If this same atom with 22 protons and 19 electrons were to gain 3 electrons, the net charge on the atom would be
mina [271]

Answer:

neutral

Explanation:

19+3=22

22 protons & 22 neutrons --> neutral net charge

3 0
3 years ago
What does the law of conservation of energy state?
Anarel [89]

Answer:

it states that the total mass of the products are the same as the total mass of the reactants in a chemical reaction.

Explanation:

4 0
3 years ago
Can someone help.? thanks :)​
laila [671]

Answer:

  • <u>1. Equation: 2x  + 3 = 9x - 11</u>

<u></u>

  • <u>2. Each row has 2 chairs</u>

Explanation:

The variable x represents the number of chairs in each row.

<u />

<u>1. She can form 2 rows of a given length with 3 chairs left over.</u>

Thus, she has:

number of rows  number of chairs in      chairs             number of chairs

                             each row                       left over         she has

     2                        x                                    3                      2x + 3

<u>2.  She can form 9 rows of the same length if she gets 11 more chairs.</u>

That means that she is short in 11 chairs to have 9x chairs, or that she has 11 less chairs than 9x chairs. Then she has:

  • 9x - 11

<u>3. Equation:</u>

Then, number of chairs she has is 2x + 3 and, also, 9x - 11, which allows to set the equation:

  • 2x + 3 = 9x  -11

<u>4. Solve the equation:</u>

  • 9x - 2x = 3 + 11
  • 7x = 14
  • x = 2

Therefore, each row has 2 chairs, and she has 2x + 3 = 4 + 3 = 7 chairs.

4 0
3 years ago
Molarity to percent by mass. Convert 1.672 mol/L MgCl2(aq) solution to percent by mass of MgCl2 in the solution. The solution de
nignag [31]

Answer:

\%m/m=14\%

Explanation:

Hello!

In this case, since the molarity of magnesium chloride (molar mass = 95.211 g/mol) is 1.672 mol/L and we know the density of the solution, we can first compute the concentration in g/L as shown below:

[MgCl_2]=1.672\frac{molMgCl_2}{L}*\frac{95.211gMgCl_2}{1molMgCl_2}=159.2\frac{gMgCl_2}{L}

Next, since the density of the solution is 1.137 g/mL, we can compute the concentration in g/g as shown below:

[MgCl_2]=159.2\frac{gMgCl_2}{L}*\frac{1L}{1000mL}*\frac{1mL}{1.137g}=0.14

Which is also the by-mass fraction and in percent it turns out:

\%m/m=0.14*100\%\\\\\%m/m=14\%

Best regards!

6 0
3 years ago
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