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
I would he would try to enter as the tide is rising, and leave as the tide is falling. Those things happen at all different times of day during a month. Hope it helps!!
Answer:
- The molar mass of the solute, in order to convert from moles of solute to grams of solute.
- The density of solution, to convert from volume of solution to mass of solution.
Explanation:
Hello,
In this case, since molarity is mathematically defined as the moles of solute divided by the volume of solution and the weight/weight percent as the mass of solute divided by the mass of solution, we need:
- The molar mass of the solute, in order to convert from moles of solute to grams of solute.
- The density of solution, to convert from volume of solution to mass of solution.
For instance, if a 1-M solution of HCl has a density of 1.125 g/mL, we can compute the w/w% as follows:
Whereas the first factor corresponds to the molar mass of HCl, the second one the conversion from L to mL of solution and the third one the density to express in terms of grams of solution.
Regards.
The nuclear reaction occurring is known as alpha-decay, and during this process, an alpha particle is released from a heavy radioactive nucleus to form a lighter more stable nucleus. The alpha particle is equivalent to a helium nucleus, which means it contains 2 protons and two neutrons (net charge of +2)
The decay equation is:
Rn → Po + α
A. the wax is a both; 1. physical change-solid to liquid.
2. chemical change- burned to CO2 + H20 + heat + carbon as seen as black on the rod
b. the wick is neither; the wick does not change, just provides conduit for wax to flame
c. the glass rod is physical change; the carbon is only deported
HOPE THIS HELPS, IVE ALSO LEARNING BEEN LEARNING THIS RECENTLY
