On a temperature versus time graph, how does the temperature at the beginning of a change of state compare with the temperature at the end of the change?

Zoe is investigating the composition of substance a, an unknown substance. using chemical processes, she analyzes substance a and determines it is composed of sodium, oxygen, and hydrogen atoms in a ratio of 1 : 1 : 1. what is substance a? a. a compound b. an element c. a heterogeneous mixture d. a homogeneous mixture

Which metal exist in liquid state and can be cut with knife ?

Name the element in group 17, period 2. (periodic table)