Answer:
C
Explanation:
when the equation is balanced, 2 moles of sodium is to 1 mole of hydrogen in the mole ratio so we need to find how many moles of sodium will produce hydrogen then we cross multiply
2Al(s) + 3Cl₂ → 2AlCl₃
Forming the equation:
2(28) + 3(223) = ΔH + 2(111)
ΔH = 503 kJ
Writing this outside of the reaction equation:
ΔH = -503 kJ
3 sf
<span>(Rules:
> Non-zero digits are always significant.
123 - 3sf
> Any zeros between two significant digits are significant.
102 - 3 sf
<span>> A final zero or trailing zeros in the decimal portion ONLY are significant.
4500 - 2 sf
0.04 - 1 sf
0.0013 - 2 sf )
</span></span>
All of the group iia metals (the column with Be, Mg, Ca, etc) have an outermost s suborbital with 2 electrons
Answer: 27 neutrons
Explanation:
Recall that the number of protons in the nucleus of an atom = Atomic number.
Hence, Calcium with mass number 47 and atomic number 20 will have 20 protons
Therefore, since Mass number = number of protons + neutrons
47 = 20 + neutrons
Neutrons = 47 - 20 = 27
Thus, there are 27 neutrons in radioactive calcium nucleus.
