Answer:
We need 7.5 mL of the 1M stock of NaCl
Explanation:
Data given:
Stock = 1M this means 1 mol/ L
A 0.15 M solution of 50 mL has 0.0075 moles NaCl per 50 mL
Step 2: Calculate the volume of stock we need
The moles of solute will be constant
and n = M*V
M1*V1 = M2*V2
⇒ with M1 = the initial molair concentration = 1M
⇒ with V1 = the volume we need of the stock
⇒ with V2 = the volume we want to make of the new solution = 50 mL = 0.05 L
⇒ with M2 = the concentration of the new solution = 0.15 M
1*V1 = 0.15*(50)
V1 = 7.5 mL
Since 0.0075 L of 1M solution contains 0.0075 moles
50 mL solution will contain also 0.0075 moles but will have a molair concentration of 0.0075 moles / 0.05 L =0.15 M
We need 7.5 mL of the 1M stock of NaCl
It's a hazard symbol for irritant.
Answer:
175 kJ
Explanation:
Activation energy can be defined as the potential energy that is needed to change reactants to products. This is the minimum energy required for the chemical reaction to take place. Thus, using the given figure:
Activation energy = activation complex - reactant energy
In the given figure, activation complex = 400 kJ
reactant energy = 225 kJ
Therefore:
Activation energy = 400 - 225 = 175 kJ
Hey there!:
Molar mass MgCl2 = 95.2110 g/mol
So:
1 mole MgCl2 -------------- 95.2110 g
moles MgCl2 ---------------- 319 g
moles MgCl2 = 319 * 1 / 95.2110
moles MgCl2 = 319 / 95.2110
=> 3.350 moles of MgCl2
Hope that helps!
Im working on science too!! I would help you but the attachment isn't pulling up..
