Answer:
2.40 M
Explanation:
The molarity of a solution tells you how many moles of solute you get per liter of solution.
Notice that the problem provides you with the volume of the solution expressed in milliliters,
mL
. Right from the start, you should remember that you must convert this volume to liters by using the conversion factor
1 L
=
10
3
mL
Now, in order to get the number of moles of solute, you must use its molar mass. Now, molar masses are listed in grams per mol,
g mol
−
1
, which means that you're going to have to convert the mass of the sample from milligrams to grams
1 g
=
10
3
mg
Sodium chloride,
NaCl
, has a molar mass of
58.44 g mol
−
1
, which means that your sample will contain
unit conversion
280.0
mg
⋅
1
g
10
3
mg
⋅
molar mass
1 mole NaCl
58.44
g
=
0.004791 moles NaCl
This means that the molarity of the solution will be
c
=
n
solute
V
solution
c
=
0.004791 moles
2.00
⋅
10
−
3
L
=
2.40 M
The answer is rounded to three sig figs, the number of sig figs you have for the volume of the solution.
Answer:
The new findings support the theory that walking first arose underwater, preceding the move onto land and the development of toes and limbs adapted to land perambulation.
Answer:- 10 L of ethane.
Solution:- The given balanced equation is:
From this equation, ethane and oxygen react in 2:7 mol ratio, the ratio of volumes would also be same if they are at same temperature and pressure.
Since 14 L of each gas are taken, the oxygen will be the limiting reactant and ethane will be the excess reactant. Let's calculate the volume of ethane used:
= 
From above calculations, 4 L of ethane are used. So, excess volume of ethane left after the completion of reaction = 14 L - 4 L = 10 L
Hence, 10 L of ethane will be remaining.
The law of conservation of mass states that mass or matter cannot be created or destroyed, only transferred or recombined.
For chemical equations, this law means that each element must be accounted for equally both for reactants and products. So the same numbers of each atom must match on each side, hence the necessity for balancing the chemical equation accurately. This created a field of chemistry called Stoichiometry, which accounts for the conservation of matter throughout chemical reactions and processes.
