3. After 7.9 grams of sodium are dropped into a bathtub full of water, how many grams of hydrogen gas are released? 4. Excess oxygen gas is added to 34.5 grams of aluminum and heated under pressure. How many grams of aluminum oxide are produced?

Please explain as well if possible!

Solution given:

3.

2Na=2*23g.

2O=18g.

=62g

=2 g

we have

2*23g of Na produce 2g of

Now

7.9 g of Na produce 2*7.9/(2*23)

=0.34g of

4.

we have

=3*16g*2g

4Al=4*27g

= 2*27*2g+2*16*3g

4*27g of Al produces 204g of

34.5g of Al produces 204g*34.5/(4*27)

answer: - 3.) the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

solution: - as per the rules, oxidation number of oxygen in its compounds is -2. the sum of oxidation numbers of all the elements of a molecule or compound is zero.

also, the oxidation number in elemental form is zero.

in no, the oxidation number of o is -2 so the oxidation number of n is +2 so that the sum is zero.

similarly, the oxidation number of c in co is +2 and o is -2.

on product side the oxidation number of n is 0 as it is in the elemental form() .

oxidation number of c in carbon dioxide is +4 as there are two oxygen in it and we know that each oxygen is -2.

so, oxidation number of n is changing from +2 to 0 and the oxidation number of c is changing from +2 to +4.

since nitrogen is reduced and hence no is acting as an oxidizing agent. carbon is oxidized and so co is acting as a reducing agent.

so, the right choice is number 3.)the oxidation state of nitrogen in no changes from +2 to 0, and the oxidation state of carbon in co changes from +2 to +4 as the reaction proceeds.

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