I have the same question too!!!Dang I thought I would get a answer I just guessed
Answer:
Option B. 28.5 amu
Explanation:
The following data were obtained from the question:
Isotope A:
Mass of A = 28.0 amu
Abundance (A%) = 14.0%
Isotope B:
Mass of B = 29.0 amu
Abundance (B%) = 66.0%
Isotope C:
Mass of C = 27.4 amu
Abundance (C%) = 20.0%
Atomic mass of element X =.?
The atomic mass of element X can be obtained by using the following formula:
Atomic mass = [(Mass of A × A%)/100] + [(Mass of B × B%)/100] + [(Mass of C × C%)/100]
Atomic mass of Element X = [(28 × 14)/100] + [(29 × 66)/100] + [(27.4 × 20)/100]
= 3.92 + 19.14 + 5.48
= 28.54 ≈ 28.5 amu
Therefore, the atomic mass of Element X is 28.5 amu
Answer:
Fe^2+(aq) + S^2-(aq) --------> FeS(s)
Explanation:
First let us look at the molecular equation;
Na2S(aq) + Fe(NO3)2(aq) --------> FeS (s) + 2NaNO3(aq)
Now, the net ionic equation usually shows the most important reaction that took place, in this case, the formation of the FeS precipitate.
Hence, ionically;
Fe^2+(aq) + S^2-(aq) --------> FeS(s)
Avagadros law states that volume of gas is directly proportional to number of moles of gas at constant pressure and temperature.
where V -volume , n - number of moles
parameters for the first instance are on the left side and parameters for the second instance are on the right side of the equation
substituting these values in the equation
V = 44.8 L
answer is C. 44.8 L
Answer:
7 sig figs.
Explanation:
Hello,
By performing the given operation:
The result is:
Thus, we notice that 700.6652 has five non-zero digits which are eligible for significant figures. Moreover, those two zeros after the 7 also are eligible for significant sigures as they are to the right of the first non-zero digit (7). Therefore, the result contains seven (7) significant figures.
Best regards.