The balanced combustion reaction for c 6 h 6 is 2 c 6 h 6 ( l ) 15 o 2 ( g ) ⟶ 12 co 2 ( g ) 6 h 2 o ( l ) 6542 kj if 7.700 g c 6 h 6 is burned and the heat produced from the burning is added to 5691 g of water at 21 ∘ c, what is the final temperature of the water

Explanation:

To calculate the moles, we use the equation:

According to stoichiometry :

2 moles of releases = 6542 kJ of heat

0.9858 moles of  release = of heat

Thus heat given off by burning 7.700 g of  will be absorbed by water.

Q = Heat absorbed= 3224kJ = 3224000J   (1kJ=1000J)

m= mass of water = 5691 g

c = specific heat capacity =

Initial temperature of the water = = 21.0°C

Final temperature of the water =  = ?

Putting in the values, we get:

The final temperature of the water is

what is the general relationship between a galaxy's distance from earth and its speed?

the answer is:

the farther away a galaxy is from us, the faster it is moving away from us.

first let us lay out the formula for potential

and kinetic energy:

pe = mgh

ke = (mv^2)/2

where: m=mass, v=velocity, g=gravitational

acceleration, h=height

calculating for mass using the known values of

pe:

340j = m (9.81 m/s^2) (50ft) (1m/3.28ft)

m = 2.27 kg

the law of conservation of energy states that

energy is neither created nor destroyed. therefore, the change in kinetic

energy from 50 ft to 35 ft would be equal to the change in potential energy

from 50 ft to 35 ft. however it would be opposite in signs since one is losing

while other is gaining.

ke(35ft) – ke(50ft) = - [ pe(35ft) – pe(50ft]

ke(50ft) = 0 since the brick is initially at rest

ke(35ft) = 340j - 2.27kg (9.81 m/s^2) (35ft)

(1m/3.28 ft)

ke(35ft)

= 102.38 j