Answer:
An example would be ice.
Explanation:
Because ice starts off as a solid and then when it melts from heat turns into a liquid and then if heated can to into a gas.
Answer:

Explanation:
Hello!
In this case, since the sulfuric acid and sodium hydroxide react in a 1:2 mole ratio, given the reaction, we realize they have the following mole ratio at the equivalence point:

Which in terms of concentrations and volumes is:

Thus, we can plug in the volume and concentration of acid to find the moles of base:

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4X + 3O₂ = 2X₂O₃
n(X₂O₃)=0.02225 mol
m(X)=4.000 g
x - the molar mass of metal
m(X)/4x=n(X₂O₃)/2
x=m(X)/{2n(X₂O₃)}
x=4.000/{2*0.02225)=89.89 g/mol
X=Y (yttrium)