It is 2.1 x 10^3 because your base number needs to be in between 1 and 10, and the number you are converting is non-decimal, so the exponent is positive. It is 10^3 because you are moving the decimal 3 places to the right
I think it’s 1 mole
If Iam not mistaken
Answer:
Volume of water at this temperature is 27.2 mL
Explanation:
We know that 
Here density of water is 0.992 g/mL
Here mass of water is 27.0 g
So 
= 
= 27.2 mL
Answer:

Explanation:
The unbalanced nuclear equation is

Let's write X as a nuclear symbol.

The main point to remember in balancing nuclear equations is that the sums of the superscripts and of the subscripts must be the same on each side of the reaction arrow.
Then
235 = 4 + A , so A = 235 - 4 = 231, and
92 = 2 + Z , so Z = 92 - 2 = 90
And your nuclear equation becomes

Element 90 is thorium, so

I think the answer would be nitrogen