Answer:
helium is the smallest element and francium is the largest
M = 0,23kg = 230g
d = 1g/cm³
V = 230g / 1g/cm³ = 230cm³ = 0,23L
The answer is -60.57 = -60.6 KJ.
CaC2(s) + 2 H2O(l) ---> Ca(OH)2(s) +C2H2(g) H= -127.2 KJ
Hf C2H2 = 226.77
Hf Ca(OH)2 = -986.2
<span>Hf H2O = -285.83
Now,
</span><span>add them up. 226.77 - 986.2 + (2*285.83) = -187.77
</span><span>Add back the total enthalpy that is given in the question
-187.77+127.2 = -60.57 </span>
As per the law of constant composition, a given sample will always contain the same number of elements that combine in the same mass proportion.
Therefore if a sample of 13.97 g of NaBr contains 22.39 % of Na by mass then, a sample of 5.75 g of NaBr would also contain 22.39% Na by mass
Hence:
Mass of Na = 5.75 g * 22.39/100 = 1.287 g
5.75 g of NaBr would contain 1.29 g of Na
Has a negative charge and emits energy when it moves to a lower energy orbit from an excited state.
electrons are NOT found in the nucleus but are actually found in rings surrounding the nucleus called orbits.
And while protons and neutrons have reltively the same mass, electrons are about 2000 times lighter.
Also: side note, when electrons move FROM a lower energy orbit INTO an excited state, it absorbs light.
