Question 1 MARKS: 1
A substance was analysed and was found to have a boiling point of 450 °C.
At room temperature it is a soft grey solid.
Which temperature could be the melting point of a pure sample of the substance?
A-12 °C
B 56 °C to 72 °C
C 250 °C to 275 °C
D
142.c

Which describes interactions between substances and stomata during photosynthesis? check all that apply. oxygen enters stomata. oxygen is released through stomata. carbon dioxide enters stomata. carbon dioxide is released through stomata. hydrogen enters stomata. hydrogen is released through stomata.

Consider the four elements above. which one of these elements will combine with oxygen in a 1: 1 ratio?

Identify the correct mole ratio for each substance. sodium chloride (nacl) na: cl = 1: ammonium nitrate (nhno) h: o = 4: