Can someone please explain how to do number 11?

HBr + Mg(OH)2 —> MgBr2 + H2O.

To balance the above, we must do a head count of the individual atoms present to ensure they balance on both sides of the equation. To get the balance equation, add 2 in front of HBr and 2 in front of H2O as shown below:

2HBr + Mg(OH)2 —> MgBr2 + 2H2O

We can see clearly that the numbers of the individual atoms on the left side is the same on the right side

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

tracks, burrows, eggshells, nests, tooth marks, or gastroliths