A new material was produced in a laboratory by bonding atoms of different elements together in a unique arrangement. Other laboratories

were able to reproduce these results, producing the same material with

the same elements in the same arrangement. What type of matter was

produced?

*

A compound

Explanation:

A compound is a substance formed from the chemical combination of atoms of two or more elements together.

A chemical compound always contains the same kinds of atoms of elements combined together in as specific ratio by mass and can be represented by a chemical formula. For example, water is a compound formed from the chemical combination of hydrogen and oxygen atoms in the ratio of 2 : 1. It has a chemical formula H2O.

A pure compound also always have the same chemical properties irrespective of the source of the compound. For example, chemically pure has similar properties irrespective of whether it is obtained from rain, streams or underground wells.

Therefore, if a new material was produced in a laboratory by bonding atoms of different elements together in a unique arrangement and other laboratories were able to reproduce these results, producing the same material with the same elements in the same arrangement, then the substance must be a compound.

n2(g) + 3h2-> 2nh3(g)   this is the balanced equation

note the mole ratio between n2, h2 and nh3.   it is 1 : 3 : 2   this will be important.

moles n2 present = 28.0 g n2 x 1 mole n2/28 g = 1 mole n2 present

moles h2 present = 25.0 g h2 x 1 mole h2/2 g = 12.5 moles h2 present

based on mole ratio, n2 is limiting in this situation because there is more than enough h2 but not enough n2.

moles nh3 that can be produced = 1 mole n2 x 2 moles nh3/mole n2 = 2 moles nh3 can be produced

grams of nh3 that can be produced = 2 moles nh3 x 17 g/mole = 34 grams of nh3 can be produced

note:   the key to this problem is recognizing that n2 is limiting, and therefore limits how much nh3 can be produced.