Answer : The mass of sample is, 267.5 grams.
Explanation :
Density : It is defined as the mass of a substance contained per unit volume.
Formula used :

Given:
Volume of Pb = 
Density of Pb = 
Now put all the given values in the above formula, we get the mass of Pb.


Therefore, the mass of sample is, 267.5 grams.
A pure substance has a constant composition and cannot be separated into simpler substances by physical means. There are two types of pure substances: elements and compounds. Elements: are pure substances made up of only l type of atom. Atoms of the same element are identical in properties.
Answer:
nvnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnv
Explanation:
1. solute is the substance that is being dissolve,while solvent is dissolving medium
2.saturated is solution that contain maximum amount of solut that capable of being dissolve and supersaturated is solution that contain less amount or medium of solut that capable being dissolve : example vinger
3. is a number placed in front of a chemical symbol or formula. It shows how many atoms or molecules of the substance are involved in the reaction. For example, two molecules of hydrogen would be written as 2 H2, and two molecules of water would be written 2 H2O . yes it's can be change only in caseWhen you balance an equation you can only change the coefficients
Answer:
7 valence electrons.
Explanation:
Oxygen lies in period 2 and group 16 of the periodic table. It is eighth element on the periodic table. Its symbol is O.
Its electronic configuration is given by:
16 = 2,8,6
It has 6 valance electrons. Its valancy is -2. It means can share share and it can gain 2 electron to get stability.
Hence, The element oxygen has <u>7</u> valence electrons.