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
D)By increasing or decreasing the size of systems that are difficult to study we make it easier for students to see how they work and therefore make it easier for them to learn.
Explanation:
Scientific models makes it easier to teach students about systems because their sizes can be adjusted and this makes it easier for students to see how they work.
A model is a simplification of the real work. It takes a part of the real world and studies it.
Models are highly desired in teaching and understanding very complex systems.
- Since a tutor owns the control of the model, they can make adjustments on them to a scale that is convenient to work with.
- Also, a part of a system can be studied one at a time making it simple for students to comprehend.
learn more:
Models brainly.com/question/1858613
#learnwithBrainly
In a non-flowering plant, the embryo is in spores found in the stem, and in a flowering plant, the embryo is in seeds found in the flower.
(don’t count on my answer but I think it might be this one and I apologize if you get it wrong)
Answer:
6
Explanation:
Any atom with the atomic number 6 is carbon and has 6 protons
P=18000000/6 zeros. not sure how to do rest
