Adults have stem cells because they are needed to repair certain tissues in the body such as in the muscles, bone marrow, skin, teeth, heart, and liver, to name a few. Thus, they can develop into many different cell types and function to replace older and damaged tissues.
A is obviously out because it leads to a volume of 125.0 milliliters of the new solution and gives you a lower concentration than you were aiming for.
D is out because you are adding 75 milliliters of the stock solution, so your concentration would be too high. You only need 25.0 milometers of stock solution per 100 milliliters of the new solution.
C is also out because it leads to 50.0 milliliters stock solution per 100 milliliters of the new solution and hence the wrong concentration.
B is by default the correct answer. It also details the correct technique. First you add the stock solution (This you know from your calculations to be 25 milliliters.) then you add the water up to the volume you needed. (Because the calculations only tell you the total volume of water not what you need to add) You also add the water last so you can rinse the neck of the flask to make sure you also get all the stock solution residue into the stock solution.
I would add the final step of stirring, but B is the only answer that can be correct.
Answer:
Explanation:
Not Many
1 mol of CO has a mass of
C = 12
O = 16
1 mol = 28 grams.
1 mol of molecules = 6.02 * 10^23
x mol of molecules = 3.14 * 10^15 Cross multiply
6.02*10^23 x = 1 * 3.14 * 10^15 Divide by 6.02*10^23
x = 3.14*10^15 / 6.02*10^23
x = 0.000000005 mols
x = 5*10^-9
1 mol of CO has a mass of 28
5*10^-9 mol of CO has a mass of x Cross Multiply
x = 5 * 10^-9 * 28
x = 1.46 * 10^-7 grams
Answer: there are 1.46 * 10-7 grams of CO if only 3.14 * 10^15 molecules are in the sample
I am not sure but this is what I think
This question uses the formula connecting mass, density and volume
Which is Density= Mass/Volume
Convert the mass in g
92.5 kg = 92,500g
7.87g/ml = 92,500/ Volume
Volume= 92,500/7.87
= 11,753.5 ml
Now since we have to give the answer in liters we can just divide by 1000 and get
11.75 litres
<span>2AlPO4 ( aq) + 3MgCl2 (aq) -> Mg3(PO4)2 (s) + 2AlCl3 (aq) </span>
<span>Right answer is D
</span>
