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:
Option E, Half life = 
Explanation:
For a first order reaction, rate constant and half-life is related as:
Where,
= Half life
k = Rate constant
Rate constant given = 
So, the correct option is option E.
Answer:
The answer is B.
Explanation:
The law of conservation of mass states that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations.
According to the law of conservation of mass, the mass of the products in a chemical reaction must equal the mass of the reactants.
The law of conservation of mass is useful for a number of calculations and can be used to solve for unknown masses, such the amount of gas consumed or produced during a reaction.
First, we'll identify the beaker containing pure water as follows:
We'll take equal masses from each of the three beakers and measure the mass of each.
We'll then identify the density of each by using the rule : density =mass/volume
Pure water will be the liquid having density equal to 1 gm/cm^3
Then, we'll differentiate between the salt and sugar solution by measuring the conductivity of each solution. Salt solution is a good conductor while solution of sugar is a bad conductor.
