A certain compound contains 4.0 g of calcium and 7.1 g of chlorine. Its relative molecular mass is 111. Find its empirical and molecular formulas

Given :

A certain compound contains 4.0 g of calcium and 7.1 g of chlorine.

Its relative molecular mass is 111.

To Find :

Its empirical and molecular formulas.

Solution :

Moles of calcium , .

Moles of chlorine , .

The ratio calcium and chlorine is 1 : 2 .

So , the empirical formula is .

Now , molecular mass of is :

So ,

Therefore , the molecular formula is also .

Hence , this is the required solution .

- "the choice that is not an indicator of a chemical change is "state of matter changes". more common than not, chemical reactions produce energy in the form of light or heat. along with energy, they also produce a new substance called the product that could be in any state of matter (solid, gas, or liquid)."

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