Bài 1: Hãy chỉ ra đâu là vật thể tự nhiên? Là vật thể nhân tạo?là vật vô sinh ?vật hữu sinh? là chất ( những từ in nghiêng) trong các câu sau:
a/ Dây dẫn diện làm bằng đồng hoặc nhôm, được bọc trong chất dẻo (nhựa)
b/ Trong thân cây mía có chứa nhiều đường, nước và chất xơ.
c/ Quần áo may bằng sợi bông(thành phần chính là xenlulozo) mặc thoáng mát hơn may bằng nilon

adding or remove a gaseous reactant or product changes the concentrations. if the concentration of reactant or product is increased, the system will shift away from the side in which concentration was increased (i.e. if the concentration of reactants is increased, the system will shift toward the products. if more products are added, the system will shift to form more reactants). conversely, if the concentration of reactant or product is decreased, the system will shift toward the side in which concentration was decreased (i.e. if reactants are removed, the system will shift to form more reactants. if the concentration of products is decreased, the equilibrium will shift toward the products).

explanation:

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.

14,16 18 reacts with group

explanation:

let the different atoms be x and y. each with four protons and same mass will be represented as follows.

mass number is number of protons + number of neutrons.

            and  

since, it is given that one has a negative charge while the other is neutral. therefore, there will be increase in number of protons and the atom will be represented as follows.

according to periodic table, mass number of beryllium is 9 and it has atomic number 4 so, the atoms will be and .  

the protons and neutrons will be located inside the nucleus whereas the electrons will be revolving around the nucleus.