ΔH<span> for the reaction = [sum of heat of formation for products] - [sum of heat of formation for reactants]
-6534 = [(12)(-393.5) + (6)(-285.8)] - (2X)
-6534 = [(-4722) + (-1714.8)] - 2X
-6534 = -6436.8 - 2X
-6534 + 6436.8 = -2X
-</span>97.2 = -2X<span>
then, divide each side by two to cancel out the numerical coefficient.
x = +48.6 kJ, which is the heat of formation for benzene.</span>
Answer:
This equation is based on twin paradox - a phenomena where one of the twin travels to space at a speed close to speed of light and the other remains on earth. the twin from the space on return discovers that the one on earth age faster.
Solution:
= 10 years
v = 0.8c
c = speed of light in vacuum
The problem can be solved by time dilation equation:
(1)
where,
t = time observed from a different inertial frame
Now, using eqn (1), we get:

t = 16.67 years
The age of the twin on spaceship according to the one on earth = 25+16.67 =41.66 years
It will reflect because polished metal is like glass or water it’s shiny and smooth
Answer:
A. It does not exhibit projectile motion and follows a straight path down the ramp.
Answer:
a)
& 
b) 
c) 
Explanation:
Given:
mass of the book, 
combined mass of the student and the skateboard, 
initial velocity of the book, 
angle of projection of the book from the horizontal, 
a)
velocity of the student before throwing the book:
Since the student is initially at rest and no net force acts on the student so it remains in rest according to the Newton's first law of motion.

where:
initial velocity of the student
velocity of the student after throwing the book:
Since the student applies a force on the book while throwing it and the student standing on the skate will an elastic collision like situation on throwing the book.

where:
final velcotiy of the student after throwing the book
b)



c)
Since there is no movement of the student in the vertical direction, so the total momentum transfer to the earth will be equal to the momentum of the book in vertical direction.


