Answer:
59.8%
Explanation:
First find the Mr of manganese (III) nitrate.
Mr of Mn(NO₃)₃ = 54.9 + (14 × 3) + (16 × 3 × 3) = <u>240.9</u>
Since we have to find the percentage composition of oxygen, we need to find the Mr of oxygen in the compound, which is:
Mr of (O₃)₃ = (16 × 3) × 3 = <u>144</u>
Now we can find percentage composition / percentage by mass of oxygen.
% composition = 
× 100
% composition = 
× 100 = <u>59.776%</u>
∴ % compostion of oxygen in maganese(III)nitrate is 59.8% (to 3 significant figures).
The mass of the atom would change. With no atoms being there then the mass would possibly change. With no neutrons then the mass of the atom will decrease
Answer:
The unknown element is Carbon.
(a) X is Carbon, its oxide is of acidic nature
(b) C+ O2 → CO2
Explanation:
We are given an unknown element that reacts with oxygen.
X + O2 → XO2
It is given that the oxide XO2 turns blue litmus red which is shown by acids, so XO2 is an acidic oxide. Also X will be a Non metal because Non metallic oxide is Acidic in nature.
The Oxide XO2 is dissolving is water. The oxide upon reacting with water will give an Acid.
XO2 type of oxide is found in the 14th group of the periodic table generally
So we have options like C, Si and Ge as these only have the Acidic oxide.
But when it comes to reactivity with water Only Carbon satisfies the need so the unknown element X is C.
CO2 + H2O → H2CO3 which is an acid.
(a) Element X is Carbon (C), The nature of the compound formed is Acidic.
(b) The reaction given will be as follows
C+ O2 → CO2
Therefore the unknown element is Carbon.
