Answer: (3) silicon
Explanation:
Element is a pure substance which is composed of atoms of similar elements.It can not be decomposed into simpler constituents using chemical reactions.Example: Silicon (Si)
Compound is a pure substance which is made from atoms of different elements combined together in a fixed ratio by mass.It can be decomposed into simpler constituents using chemical reactions. Example: ethane 
, propanone 
and water 
Answer:
one advantage of KLO3 as a primary standard is that it is used to know concentration of a solution.
Explanation:
The reaction provides confirmation that the solution is at a specific concentration. Primary standards are often used to make standard solutions (a solution with a precisely known concentration
Explanation:
Sugar - Pure substance
Magnesium Ribbon - Pure Substance
Vegetable soup Heterogeneous mixture
Bath oil - Homogeneous mixture
Tin of assorted biscuits - Heterogeneous mixture
Peanuts and raisins - Heterogeneous mixture
Copper wire - Pure Substance
Bicarbonate of soda (Baking soda) - Pure Substance
The tubes 1, 5 and 6 is the answer to the question which test tubes were used to determine the optimal ph lipase activity. Lipase is an enzyme and optimum ph the maximum possible point on which enzyme become active.
