Calculate the amount in grams of Na2CO3 needed in a reaction with HCl to produce 120g NaCl?

1 answer:

8 0

The balanced chemical reaction is written as :

Na2CO3<span> + 2HCl === 2NaCl + H2O + CO2
</span>
We are given the amount of NaCl to be produced from the reaction. This will be the starting point for the calculations. We do as follows:

120 g NaCl ( 1 mol / 58.44 g) ( 1 mol Na2CO3 / 2 mol NaCl)( 105.99 g / 1 mol ) = 1108.82 g Na2CO3 needed

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If element x forms the oxides xo and x2o3 the oxidation numbers of element x are

Deffense [45]

Answer:

b) +2 and +3.

Explanation:

Hello,

In this case, given the molecular formulas:

$XO$

And:

$X_2O_3$

We can relate the subscripts with the oxidation states by knowing that they are crossed when the compound is formed, for that reason, we notice that oxygen oxidation state should be -2 for both cases and the oxidation state of X in the first formula must be +2 since both X and O has one as their subscript as they were simplified:

$X^{+2}O^{-2}$

Moreover, for the second case the oxidation state of X should be +3 in order to obtain 3 as the subscript of oxygen:

$X_2^{+3}O_3^{-2}$

Thus, answer is b)+2 and +3

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3 0

3 years ago

White phosphorus is composed of tetrahedral molecules of P4 in which every P atom is connected to three other P atoms. In the Le

Dmitrij [34]

Answer:

In the Lewis structure of P4 there are 6 bonding pairs and 4 lone pairs of electrons.

Explanation:

The structure of tetrahedral molecule of P4 is provided below.

Each phosphorus atom has 5 valence electrons out of which 3 electrons involve in bonding and the rest 2 electrons exist as a lone pair that does not involve in bonding.Hence each phosphorus atom has one lone pair.In P4 molecule there are phosphorus atoms and hence 4 lone pairs in total.

As you can see in the figure, each phosphorus atom is bonded to the other three atoms.A bond is formed when two atoms share one electron each and the pair is called bonding pair.

From the figure we can see that there are 6 bonds in total.Each bond consist of one bonding pair of electrons and hence in total there are 6 bonding pairs of electrons.

Hence in a P4 molecule there are six bonding pairs and 4 lone pairs of electrons.