The elements are listed in order of increasing the atomic number. Its the number that is the number of protons in the nucleus of an atom.
Answer:
8 liters of the first salt solution and 12 liters of the second salt solution is needed to get 20L of a solution that is 30% salt
Explanation:
Let x represent the liters of the first salt solution
Let y represent the liters of the second salt solution
x + y= 20......equation 1
x= 20-y
The first solution is 20% salt and the second solution is 45% salt
20/100x + 45/100 y= 30/100 × 20
0.2x + 0.45y= 0.3×20
0.2x + 0.45y= 6............equation 2
Substitute 20-y for x in equation 2
0.2(20-y) + 0.45y= 6
4-0.2y+ 0.45y= 6
4 + 0.25y= 6
0.25y= 6-4
0.25y= 2
y= 2/0.25
y= 8
Substitute y for 8 in equation 1
x + y= 20
x + 8=20
x= 20-8
x= 12
Hence 8 liters of the first salt solution and 12 liters of the second salt solution is needed to get 20L of a solution that is 30% salt.
Answer:
Use a 10 mL pipet and a 50 mL volumetric flask, <em>twice</em>
Explanation:
Given those conditions, in order to have a solution that is 25 times less concentrated that the one previously prepared, we would need two dillution steps, as suggested by the problem.
If we take an aliquot of 10 mL and dilute it to a final volume of 50 mL, we prepare a solution that is 5 times less concentrated. And if we then take again an aliquot of 10 mL of that dilluted solution and dilute it to a final volume of 50 mL, we would have a solution 25 (5 times 5) times less concentrated than the original one.
In order to verify, we can calculate the resulting concentration and compare it with the original one:
Thus we can see that the obtained concentration is in fact 25 times lower than the original concentration.
The energy released in a nuclear reaction may appear only in one of these three ways Kinetic energy of the products. The emission of gamma rays. And gamma rays are emitted by unstable nuclei in their own transition that is from a high energy state that than goes to a lower energy state that is properly known as gamma decay.
A mole<span> is a unit of measurement. One </span>mole<span> equals 6 x 10^23 atoms/molecules/whatever. So take the </span>molecular mass<span> of elemental </span>oxygen<span> - 16 grams per </span>mole<span>. ... 1 </span>mole<span> elemental </span>oxygen<span>(16 grams O/1 </span>mole<span>) = 16 grams.</span>
