Dalton's atomic theory states a) that an atom is predominantly empty space. b) that matter is composed of small indestructible particles. c) that the properties of matter are determined by the properties of atoms. d) that energy is neither created nor destroyed during a chemical reaction. e) that all elements have several isotopes. 2) identify a solid. a) definite volume and definite shape b) definite volume and no definite shape c) definite shape and no definite volume d) no definite shape and no definite volume 3) a substance that can't be chemically broken down into simpler substances is a) a homogeneous mixture. b) an element. c) an electron. d) a heterogeneous mixture. e) a compound. 4) two or more substances in variable proportions, where the composi

1.B. That matter is composed of small indestructible particles.  

2.A. Definite volume and definite shape.

3.B. An element

Explanation:

1.Dalton's atomic theory postulates:

1.It states that matter is composed of atoms that are  indivisible and indestructible.

2.Atoms of an elements are identical .They have same size ,chemical properties and mass.

3.Atoms of one element are different from atoms of another elements.

4.Compounds are composed of atoms of more than one elements.The relative number of atoms of each element in a given compound is always same.

5.Atoms are not created or destroyed during chemical reaction.

B.That matter is composed of small indestructible particles.  

2.Solid:It is that form of substance which have definite shape and definite volume.

Therefore, option A is true.

A. Definite volume and definite shape.

3.An element: it is a simpler substance .It cannot be broken into smaller substance by chemical reactions.

Therefore, option B is true.

B. An element

as given the equation is

2al + 6 hcl > 2 alcl3 + 3 h2(g)

as per equation two moles of aluminum reacts with six moles of hcl to give two moles of alcl3 and three moles of hydrogen gas

given: three moles of al are present and 7 moles of hcl

for three moles of aluminum nine moles of hcl will be required

however as 7 moles of hcl are present so the limiting reagent is hcl

hcl is going to decide the number of moles of product formed

when six moles of hcl are present = 3 moles of h2 are formed

when one mole of hcl is present == 3/6 mole sof h2 will be formed

when 7 moles of hcl are present = 3 x 7/ 6 moles of h2 will be formed = 3.5 moles of h2