Answer:
1)Reactants
2)Light
3)An item that can increase reaction rates
4)Reactants must collide with each other
Less molecules lower the chance for collisions
The more collisions there are the higher the reaction rate
Answer:
30 Liters of 40% acid solution and 10 L of 60% acid solution is needed.
Explanation:
Let volume of the 40% acid solution be x.
Let volume of the 60% acid solution be y.
Volume of solution formed after mixing both solution = 40 L
x + y = 40 L..[1]
Volume of acid 40% solution = 40% of x= 0.4x
Volume of acid 60% solution = 60% of y= 0.6y
Volume of acid formed = 45% of 40 L = 
..[2]
Solving [1] and [2]
x = 30 L , y = 10 L
30 Liters of 40% acid solution and 10 L of 60% acid solution is needed.
1 atom Mg, 2 atoms O and 2 atoms H.
1 + 2 + 2 = 5, so correct answer is C