How much lower should the melting point of a crude substance be compared to that of the pure compound?

Write the chemical symbols for three different atoms or atomic cations with 27 electrons. asap!

Substance x has a fixed volume, and the attraction between its particles is strong .substance y had widely spread out particles and can be compressed what can most likely be concluded about these substances

Which of the following is most likely true about water in chemical systems? a) water dissolves nonpolar ionic compounds. b) water dissociates ionic compounds. c) water dissociates covalent molecules. d) water dissolves nonpolar covalent substances.