Answer: Rubber source, temperature, thinkness, thread design, driving pattenrs, weather, etc.
Explanation: There are many variables. Here are a few I would include in a tire lifetime study:
1. Type of rubber, including source
2. Thickness of tire
3. Design of tire thread
4. Life as a function of average speed and road surface
5. Expected outside temperature and wet conditions
6. Driving conditions of speed and both acceleration and deceleration parameters (e.g., tire life when slamming on the brakes or accelerating quickly)
Answer:
3-ethyl-4-methyl Heptane
Explanation:
longest chain is straight .
we start assigning number from where we are close to the branch to this mean its from left hand side. and we saw two chain 1 is ethyl and other is methyl . In alphabetical order e comes first as compare to m so we write ethyl first after that methyl and than in last we write longest chain name with ane (bcz we only have single vonds).
Explanation:
Calcium is the element that has 2 valence electrons.
Answer : The balanced chemical equation is,

Explanation :
Balanced chemical equation : It is defined as the number of atoms of individual elements present on the reactant side must be equal to the number of atoms of individual elements present on product side.
The given unbalanced chemical reaction is,

This chemical reaction is an unbalanced reaction because in this reaction, the number of atoms of individual elements are not balanced.
In order to balanced the chemical reaction, the coefficient 2 is put before the
, the coefficient 3 is put before the
and the coefficient 4 is put before the
.
The energy evolved in this reaction = 
Thus, the balanced chemical reaction will be,
