Answer:
Check explanation
Explanation:
In the formation of calcium fluoride we take calcium and fluorine.
in elemental form calcium exist in solid form and fluorine in gaseous form.
formation of compound takes place to complete their octet, in case of calcium need to remove two electron and need to add one elecron in fluorine to complete their octet so two electron will ransferred from calcium to two fluorine atom.
Answer:

Explanation:
Time to mow 1 lawn by Wilma is 80 minutes
so work done in 1 minute by Wilma is given as
Similarly Rocky mow same lawn in 120 minute
so work done in 1 minute by Rocky is given as

now we know that they both worked by "t" time
so total work performed by them

they both mow 2 lawns then it is given as


The answer is B.
A cannot be the answer is melting is a physical change. No chemical reaction took place.
B is the answer as it is a EXOTHERMIC REACTION so heat will be given off.
C cannot be the answer as dissolving is basically atoms becoming ions, not a chemical reaction whereby a reactant reacts with another reactant to form a product.
D cannot be the answer. Same reason as for why A is not the answer.
Cheers.
Answer:
Car H
Explanation:
Frictional force is a resistant force. It is given as:
F = u*m*g
Where u = coefficient of friction
m = mass
g = acceleration due to gravity
From the formula above, we see that frictional force is dependent on the mass of object and the coefficient of friction.
Since they all have the same tires, the coefficient of friction between the tire and the floor is the same for each car. Acceleration due to gravity, g, is constant.
The only factor that determines the frictional force of each car is the mass. Hence, the more the mass, the more the frictional force.
So, the most massive car will have the most frictional force and hence, will come to a stop quicker than the others. The least massive car will have the least frictional force and so, will take a longer time to stop.