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2 years ago

What is the atomic number and mass number of calcium ?

Chemistry

1 answer:

solniwko [45]2 years ago

7 0

Answer:

Calcium has an Atomic number of 20 and Atomic mass of 40.078 u

Hope this helps!

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1. When iron is oxidized, what is reduced?

lys-0071 [83]

Answer:Oxygen

Explanation:

Oxygen gets reduced when iron is oxidized.

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3 years ago

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Molecules in 2 moles of carbon dioxide

Maksim231197 [3]

Answer:

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3 years ago

Suppose you need to prepare 141.9 mL of a 0.223 M aqueous solution of NaCl. What mass of NaCl do you need to use to make the sol

Afina-wow [57]

Answer:

1.811 g

Explanation:

The computation of the mass need to use to make the solution is shown below:

We know that molarity is

$Molarity = \frac{Number\ of\ moles}{Volume\ in\ L}$

So,

$Number\ of\ moles = Molarity\ \times Volume\ in\ L$

$= 0.223\times 0.141$

= 0.031 moles

Now

$Mass = moles \times Molecualr\ weight$

where,

The Molecular weight of NaCl is 58.44 g/mole

And, the moles are 0.031 moles

So, the mass of NaCL is

$= 0.031 \times 58.44$

= 1.811 g

We simply applied the above formulas

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3 years ago

1. How is different kind of molecules different? And similar?

dexar [7]

Answer:

1.Molecules are made of atoms. So different molecules can have different (or same) number of atoms they are made of.Different atoms are made of different number of protons of neutrons in the nucleus (also electrons around the nucleus but they are very small even compared to atom and don’t add up for volume or mass) therefore their radius and mass are different.

2.Chromatography works because of differences in the properties of molecules in materials.some molecules differ in shape and size. These differences in molecular properties allow scientists to separate compounds into individual molecules using chromatography.

Explanation:

hope this helps

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2 years ago

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What volume of 0.152 M KMnO4 solution would completely react with 20.0 mL of 0.381 M FeSO4 solution according to the following n

ANEK [815]

Answer: The volume of permanganate ion (potassium permanganate) is 10.0 mL

Explanation:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$ .....(1)

Molarity of ferrous sulfate solution = 0.381 M

Volume of solution = 20.0 mL = 0.020 L (Conversion factor: 1 L = 1000 mL)

Putting values in equation 1, we get:

$0.381M=\frac{\text{Moles of ferrous sulfate}}{0.020L}\\\\\text{Moles of ferrous sulfate}=(0.381mol/L\times 0.020L)=0.00762mol$

For the given chemical equation:

$5Fe^{2+}+8H^++MnO_4^-\rightarrow 5Fe^{3+}+Mn^{2+}+4H_2O$

By Stoichiometry of the reaction:

5 moles of iron (II) ions (ferrous sulfate) reacts with 1 mole of permanganate ion (potassium permanganate)

So, 0.00762 moles of iron (II) ions (ferrous sulfate) will react with = $\frac{1}{5}\times 0.00762=0.00152mol$ of permanganate ion (potassium permanganate)

Now, calculating the volume of permanganate ion (potassium permanganate) by using equation 1, we get:

Molarity of permanganate ion (potassium permanganate) = 0.152 M

Moles of permanganate ion (potassium permanganate) = 0.00152 mol

Putting values in equation 1, we get:

$0.152mol/L=\frac{0.00152mol}{\text{Volume of permanganate ion (potassium permanganate)}}\\\\\text{Volume of permanganate ion (potassium permanganate)}=\frac{0.00152mol}{0.152mol/L}=0.01L=10.0mL$

Hence, the volume of permanganate ion (potassium permanganate) is 10.0 mL

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3 years ago