Answer:
<em>The correct option is B) two liquids are mixed at room temperature and a gas forms.</em>
Explanation:
A chemical change can be described as a change which results in the formation of a new substance by the reactants. In the option B, two liquids react to form a new product which is a gas. Hence, it is an example of chemical change.
Other options,like option D, is not a chemical change as by crushing a solid no new product is formed. Option C is also not correct because as when salt dissolves in water, no new product is made.
To get the molarity you need to follow this equation
moles of solute
Molarity (M = -----------------------
Liters of solution
But before you apply that equation you need to find the moles of solute and the liters of solution. Follow this equation
Na2SO4 + BaCl2 = BaSO4 + 2 NaCl
Solution
Moles of BaSO4 = 5.28 g
---------------
233.43 g / mol
= 0.0226 moles
Moles of NaSO4 = 0.0226
0.0226 mole
Molarity = -----------------
0.250 L
= 0.0905 mol / L
So the answer is 0.0905 mol / L
The first option: the basic unit of the nervous system
Yes a red blood cell placed in a sline solution shrinks because of the process of osmosis.
Good laboratory technique demands clean glassware because the most carefully executed piece of work may give an erroneous result if dirty glassware is used. In all instances, glassware must be physically and chemically clean and in many cases, it must be bacteriologic-ally clean or sterile.
