The differences are the freezing and boiling points being exactly 180 degrees
5. B air is a mixture of many elements, but is not a chemically fused.
6. B Beef stew, composition varies throughout.
7. A. They can be chemically separated into their component elements, but they are all homogenous, and as such, have constant composition, which differs from the components properties, as the components must undergo a chemical change to become compounds.
Answer:
+125.4 KJmol-1
Explanation:
∆H C4H10(g) = -2877.6kJ/mol
∆H C(s)=-393.5kJ/mol
∆H H2(g) = -285.8
∆H reaction= ∆Hproducts - ∆H reactants
∆H reaction= (-2877.6kJ/mol) - [4(-393.5kJ/mol) +5(-285.8)]
∆H reaction= +125.4 KJmol-1
1) Dalton stated that atom is matter that can not be divided, but it is proved that the atom can be divided into subatomic particles (electrons, protons and neutrons).
2) He stated that atoms of one element can not be changed into atoms of other elements, but now that is possible by nuclear reactions.
Today we still use his postulate: Atoms combine in the ratio of small whole numbers to form stable compounds, for example H₂O.
Gets exited and moves at a faster constant speed
