Which statement best explains why elements are matter?

a) the building blocks of elements are small particles called atoms
b) elements are pure substances that cannot be divided chemically
c) an element is a physical substance that has mass and takes up space

A) The building blocks of elements are small particles called atoms

Explanation:

There are four kinds of matter: solids, liquids, gas and plasma. According to Charles Darwin all matter is made up atoms. Elements are matter because they are made up of the atoms. In elements all the atoms are the same making elements pure substances and not mixtures. An atom is the smallest part of an element and has all the properties of the element.

answer: semi-infinite solid initially at a uniform temperature of 400 ◦c is cooled at its surface by convection. the cooling fluid at a constant temperature of 200 ◦c has a convective coefficient (ha) of 250 w/m2.k. the physical properties of the solid: k = 20 w/m.k and α = 4 * 10-5  m2/s. using δx = 0.04 m and δt = 10 s. write the finite difference equations describing the transient heat transfer of the first five δx and the temperature profile after 30 s.