Answer:
The statements which are true among these are: (a),(b) and (c) because,
(a) The simplest organic compounds which contains only carbon and hydrogen atoms are called hydrocarbons.
(b) The IUPAC naming of organic compounds have some rules for the naming of compounds, which consists of
- Finding the longest chain present in the compound called parent chain.
- A prefix for any substituent attach to the parent chain.
And lastly a suffix for the type of bond that molecule have.
(c) Isomers are the compound which same same molecular formula but different arrangement of molecules, due to this different arrangement they have different physical and chemical properties.
Answer:
Radioactive isotopes ranging from 11O to 26O have also been characterized, all short-lived. The longest-lived radioisotope is 15O with a half-life of 122.24 seconds, while the shortest-lived isotope is 12O with a half-life of 580(30)×10−24 seconds (the half-life of the unbound 11O is still unknown).
Answer : The mass of the water in two significant figures is, 
Explanation :
In this case the heat given by the hot body is equal to the heat taken by the cold body.
where,
= specific heat of iron metal = 
= specific heat of water = 
= mass of iron metal = 32.3 g
= mass of water = ?
= final temperature of mixture = 
= initial temperature of iron metal = 
= initial temperature of water = 
Now put all the given values in the above formula, we get
Therefore, the mass of the water in two significant figures is,
Explanation:
The pH is a 1 to 14 scale that measures how acidic or basic is a solution, at lowest number the solution will be acid, in 7 the solution will be neutral, and in higher values will be basic. It is a logarithmic scale, so with each number you move, the acidity or basicity will be increased by a factor of 10. So, lemon juice is more acidic than orange juice by a factor of 100.
