The question has missing information, the complete question is:
Cobalt(II) chloride forms several hydrates with the general formula CoCl₂.xH₂O, where x is an integer. If the hydrate is heated, the water can be driven off, leaving pure CoCl₂ behind. Suppose a sample of a certain hydrate is heated until all the water is removed, and it's found that the mass of the sample decreases by 22.0%. Which hydrate is it? That is, what is x?
Answer:
CoCl₂.26H₂O
Explanation:
The molar masses of the compounds that forms the hydrate are:
Co = 59 g/mol
Cl = 35.5 g/mol
H = 1 g/mol
O = 16 g/mol
The molar mass of CoCl₂ is 130 g/mol and of H₂O is 18 g/mol, thus for the hydrate, it will be 130 + 18x g/mol.
Let's suppose 1 mol of the compound. Thus, the mass of the hydrate is: 130 + 18x, and the mass of CoCl₂ will be 130 g. Because the mass decreassed by 22.0% :
0.22*(130 + 18x) = 130
130 + 18x = 590.91
18x = 460.91
x ≅ 26
Thus, the hydrate is CoCl₂.26H₂O
Recall that most atoms are stable when their outermost ring has eight electrons. (Some atoms, such as lithium and beryllium, are stable when their outermost ring has two electrons.)
Answer:
Explanation:
The formula for the amount heat q absorbed by a substance is
q = mcΔT
where
m = the mass of the substance
C = the specific heat capacity of the material
ΔT = the temperature change
Data:
q = 2267 J
m = 44.5 g
T₁ = 33.9 °C
T₂ = 288.3 °C
Calculations:
ΔT = (288.3 - 33.9) °C = 254.4 °C
