Answer:
the mas is .291 g
Explanation:
the mass of a object does not change. so when added the substance the beaker. you had the mass of both objects together. you know the mass of the beaker and you know the mass of both. since mass does not change. the beakers mass is still 74.605g. the mass of both objects is 74.896. all you have to do is subtract the mass of the beaker from the total mass. 74.896 - 74.605 equals .291g. so the mass of the unknown substance Is .291g
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
The first part is C a substitution and the second part is A i believe, please check with others first
It should be I, Br, Cl, F
