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3 years ago

How can I calculate the valence electrons of ions?

Chemistry

1 answer:

DIA [1.3K]3 years ago

8 0

First of all, you should know the valence electron of atom.

Then add charge, In case of -ve ion & subtract, in case of +ve ion.

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If 16.29 grams of Na2SO4 is mixed with 3.697 grams of C and allowed to react according to the balanced equation: Na2SO4(aq) + 4

abruzzese [7]

Answer: The limiting reagent in the given chemical reaction is carbon metal.

Explanation:

Excess reagent is defined as the reagent which is present in large amount in a chemical reaction.

Limiting reagent is defined as the reagent which is present in small amount in a chemical reaction. Formation of product depends on the limiting reagent.

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

For sodium sulfate:

Given mass of sodium sulfate = 16.29 g

Molar mass of sodium sulfate = 142 g/mol

Putting values in equation 1, we get:

$\text{Moles of sodium sulfate}=\frac{16.29g}{142g/mol}=0.115mol$

For carbon:

Given mass of carbon = 3.697 g

Molar mass of carbon = 12 g/mol

Putting values in equation 1, we get:

$\text{Moles of carbon}=\frac{3.697g}{12g/mol}=0.31mol$

For the given chemical reaction:

$Na_2SO_4(aq.)+4C(s)\rightarrow Na_2S(s)+4CO(g)$

By Stoichiometry of the reaction:

4 moles of carbon reacts with 1 mole of sodium sulfate

So, 0.31 moles of carbon will react with = $\frac{1}{4}\times 0.31=0.0775mol$ of sodium sulfate

As, given amount of sodium sulfate is more than the required amount. So, it is considered as an excess reagent.

Thus, carbon metal is considered as a limiting reagent because it limits the formation of product.

Hence, the limiting reagent in the given chemical reaction is carbon metal.

4 0

3 years ago

A metal oxide with the formula mo contains 15.44% oxygen. in the box below, type the symbol for the element represented by m.

lana66690 [7]

Answer: The element represented by M is Strontium.

Explanation:

Let us consider the molar mass of metal be 'x'.

The molar mass of MO will be = Molar mass of oxygen + Molar mass of metal = (16 + x)g/mol

It is given in the question that 15.44% of oxygen is present in metal oxide. So, the equation becomes:

$\frac{15.44}{100}\times (x+16)=16g/mol\\\\(x+16)=\frac{16g/mol\times 100}{15.44}\\\\x=(103.626-16)g/mol\\\\x=87.62g/mol$

The metal atom having molar mass as 87.62/mol is Strontium.

Hence, the element represented by M is Strontium.

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3 years ago

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The Earth rotates about its axis from west to east. What piece of evidence about the Moon can we use to support this statement?

Debora [2.8K]

The Earth's rotation has no relation to the phases of the moon.
Like everything else in the sky, the moon rises in the east just like the stars, planets, and the sun.

8 0

3 years ago

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Upon balancing the equation below, how many moles of sulfuric acid are needed to react completely with 8.4 moles of lithium hydr

maks197457 [2]

The answer is b. 4.2 mole. The balanced reaction formula is 2LiOH + H2SO4 -->Li2SO4 + 2H2O. And the ratio of mole number of the reactants is the same as the ratio of coefficients.

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3 years ago

Please help me with these 3 questions with will be giving out brainiest

Anna71 [15]

Answer: All of them are true

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3 years ago