The diagram shows one way the properties of a polymer can be changed. What does the diagram show? Choose the correct answer
making polymer chains shorter
adding polymer chains to water
linking polymer chains together
making a net out of polymer chains

The boiling point of propanoic acid is higher than that of 1-butanol because: propanoic acid has a higher molecular weight than 1-butanol. propanoic acid is more soluble in water than 1-butanol. propanoic acid is a better hydrogen bond donor than 1-butanol. propanoic acid forms hydrogen bonded dimers and 1-butanol does not. 1-butanol forms hydrogen bonded dimers and propanoic acid does not.

Stage in which a typical star has completely stopped fusion

Precision can be defined as the o exact center of a data set. o reproducibility of a measured value. o correlation between two variables that are measured in a data set agreement between a measured value and an accepted value.