Answer:it’s C
Explanation:
A distant luminous object travels rapidly away from an observer.
We subtract the enthalpies of the reactants from that of the products:

Since this is < 0, this is an exothermic reaction.
Answer:
m = 4.7 μg
Explanation:
Given data:
density of acetone = 60.0 μg/L
Volume = 79.0 mL
Mass = ?
Solution:
Formula:
d = m/v
v = 79.0 mL × 1L /1000 mL
v = 0.079 L
Now we will put the values on formula:
d = m/v
60.0 μg/L = m/0.079 L
m = 60.0 μg/L × 0.079 L
m = 4.7 μg
So health risk limit for acetone = 4.7 μg
Explanation:
The given data is as follows.
= 10 mM =
M
= 750 ml,
= 5 ml
= ?
Therefore, calculate the molarity of given NaCl stock as follows.


= 1.5 M
Thus, we can conclude that molarity of given NaCl stock is 1.5 M.
To Find :
The horizontal range of a projectile launched at 15 degrees to the horizontal with speed of 40 m/s.
Solution :
The horizontal range of a projectile is given by :
( Here, g is acceleration due to gravity = 10 m/s² )
Putting all value in above equation :

Therefore, the horizontal range of projectile is 80 m.