Counting gives an exact number and exact numbers have infinite sig figs.
Answer:
protons = atomic numbermass number = protons + neutronsatomic number = mass number - neutrons = 78-38 = 40
Explanation:
Answer:
1, just I) color.
Explanation:
Physical properties are the properties that can be observed without changing the composition of a substance, such as color, temperature, density, and boiling point.
A physical change is a change in the substance that only modifies its aggregation state, such as solidification, and boiling.
Chemical properties are the properties that need a reaction to being observed, such as the combustibility, which needs a combustion reaction to being quantified.
When a chemical reaction occurs, and the composition of the substance change, it's a chemical change.
So, the heating copper with carbon is a chemical reaction, and purification by electrolysis is too. Color is the only physical property.
Answer:
C. 3
Explanation:
12.0 - 3 significant figures 1,2 and 0, because 0 is after decimal point.
