Answer:
(d) burning a log.
(b) toasting a slice of bread;
Explanation:
Chemical change -
A chemical change refers to , the change in which a new compound is formed .
From the question ,
Its is not a chemical process , since no new compound is formed , these is only change in state as the liquid is turning to gaseous sate .
It is not a chemical process , as no new substance is formed .
- toasting a slice of bread
It is a chemical change , in which bread surface is deposited by a brown coat via the process of heating , even this process is a irreversible in nature .
It is a chemical change , as with the help of heating , the wood is turning to ashes .
Answer:
The Bohr model suggested that electrons orbited the nucleus in circular paths where as the modern model views the atom to consist of positively charged nucleus surrounded by electrons.
Explanation:
In the modern model, the nucleus contains two sub-atomic particles, the protons which are positively charged and the neutrons which are not charged.According to Bohr's model,the electron in a hydrogen atom travel around the nucleus in a circular orbit. In the modern model, electrons do not move around nucleus around circular obits.
Answer:
Mn(NO3)3 Molar mass = (54.93) + (3 x 14) + (9 x 16) = 240.93g/mol
Total number of Oxygen atoms in formula = 9
Total mass of oxygen atoms theoretically in the formula = 9x16 = 144g/mol
Oxygen's percentage composition:
(144/240.93) x 100 = 59.7% of the compound is oxygen
