Which one of the following statements is correct? a. a pure substance may be separated by filtration or distillation into two or more components. b. a heterogeneous mixture is also known as a solution. c. a heterogeneous mixture is composed of two or more substances in the same phase. d. the composition is uniform throughout a homogeneous mixture. e. the combination of a liquid and a solid always results in a heterogeneous mixture.

Option (D) is the correct answer.

Explanation:

For example, is a molecule and it is a pure substance.

Also, substances that contain two or more different element which are chemically combined in a fixed ratio by mass are known as compounds. They are also pure substances.

A pure substance can only be separated by a chemical method and not by any physical method.

For example, mud dissolved in water.

It is not necessary that two or more substance present in a heterogeneous mixture should be of same phase.

Also, it is not necessary that combination of a liquid and a solid always results in a heterogeneous mixture.

If the solid is able to dissolve completely into the liquid then it will result in a homogeneous mixture.

For example, salt dissolved in water is a homogeneous mixture.

Thus, we can conclude that the statement composition is uniform throughout a homogeneous mixture, is correct.

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