Which statement describes a physical change?
a.
sodium metal reacts explosively with oxygen.
b.
lead is heated and becomes more viscous.
c.
calcium is added to acid and hydrogen gas is produced.
d.
iron combines with oxygen to form rust.

What is the main purpose of patent attorneys? defend the company against legal claims manage financial investments invent new products protect rights to new products and processes

One way in which the useful metal copper is produced is by dissolving the mineral azurite, which contains copper(ii) carbonate, in concentrated sulfuric acid. the sulfuric acid reacts with the copper(ii) carbonate to produce a blue solution of copper(ii) sulfate. scrap iron is then added to this solution, and pure copper metal precipitates out because of the following chemical reaction: (s) (aq) (s) (aq) suppose an industrial quality-control chemist analyzes a sample from a copper processing plant in the following way. he adds powdered iron to a copper(ii) sulfate sample from the plant until no more copper will precipitate. he then washes, dries, and weighs the precipitate, and finds that it has a mass of .

Imagine one batch of soup (batch “a”) is made with 8.19 g/can of salt, according to the recipe, and a second batch of soup (batch “b”) is made with 8.32 g/can of salt. explain which batch would be more resistant to frost damage if it is shipped a great distance in winter and explain why.