As i am reading the problem, i notice they give two concentrations (M), a volume and asking for the other volume; this should be a hint that we need to use the dilution formula---> M1V1 = M2V2
M1= 2.55 M
V1= ?
M2= 0.75 M
V2= 125 mL
now, we plug in the values into the formula
(2.55 x V1) = (0.75 x 125)
V1= 36.8 mL
The deflection of alpha particles in Rutherford's experiment proved THE ADDITION OF A SMALL, DENSE NUCLEUS TO THE CENTRE OF THE ATOM.
Answer:
2nd option
Explanation:
Molarity is the number of moles of the solute (NaCl) in 1 litre of the solution (NaCl solution).
Given: concentration= 232g/ L
what we are trying to achieve is __mol/ L.
So in 1 litre, we have 232g of NaCl.
To convert mass to mole, we divide it by the Mr.
Given that the Mr is 58g/mol,
number of moles
= 232 ÷58
= 4
Thus, 1 litre has 4 moles of NaCl.
Therefore, the molarity is 4.0 mol/L.
<span>Avogadro's number
represents the number of units in one mole of any substance. This has the value
of 6.022 x 10^23 units / mole. This number can be used to convert the number of
atoms or molecules into number of moles.
</span><span>7.3x10^-3 g of CaSO4 ( 1 mol / 136.14 g ) = 5.36x10^6-5 moles
</span> 5.36x10^6-5 moles ( 6.022 x 10^23 formula units / mole ) = 3.23x10^19 formula units