Why are the reactions listed in column a classified as chemical reactions?

i think it is D.

Step-by-step explanation:

because If a physical change occurs, the physical properties of a substance will change, but its chemical identity will remain the same. I hope this helps!

38.5

step-by-step explanation:

lets say, first number = r

second number = 3r+7

total = 49

(r)+(3r+7)= 49

4r+7 = 49

4r = 42

r = 42/4

r= 10.5

3r+7 = 3(10.5)+7 = 38.5

hope this

question:

could we have options?