M (NaCl) = n × M = 3.75 × 58.5 =
219.375 g
M (NaCl) = 23 + 35.5 = 58.5 g/mol
The Big Bang probably occurred.
~30,000 B.C. North America Asian hunter-gatherers had crossed over the frozen Bering Strait to become first humans in North America.
~10,000 B.C. South America Those who crossed over on Bering Strait into North America had traveled as far south as Argentina by this point.
~6,000 B.C. Europe End of land bridge between Britain and continental Europe. Britain becomes an island.
~4,500 B.C. Brittany (France) The megalithic structures of Carnac were built.
~3,500 B.C. Wales Pentre Ifan is built.
~3,200 B.C. Ireland The Newgrange tomb is built.
C) a chemical change.
Chemical reactions will always convert a certain chemical(s) into one or more products.
<span>Aluminum Oxide Formula</span>
Answer 1) Butane : It is a compound which is made up by combination of elements of carbon and hydrogen together. It contains four carbon atoms which has ten atoms of hydrogen. The bonds between carbon and hydrogen are formed by covalently sharing of electrons. Therefore, butane is a compound.
Answer 2) Benzene : It is also a compound. Benzene contains six molecules of carbon and six molecules of hydrogen. They are covalently bonded with hydrogen atoms around the carbon atoms. It is termed as compound because it cannot be separated chemically.
Answer 3) Gasoline : This is an example of mixture. Gasoline usually contains mixture of many hydrocarbons in the compound state. It consists of mainly hydrocarbons which are between 4 to 12 carbon atoms per molecule (C4 - C12). It is majorly has the mixture of paraffins (which are alkanes), cycloalkanes (which are naphthenes), and olefins (which are alkenes). So, it will be correct to assign the term mixture to gasoline.
Answer 4) Kerosene - It is a mixture. Kerosene is made up of mixture of hydrocarbons. The chemical composition mainly depends on its source, but it usually consists of about ten different hydrocarbons, where each contains ten to sixteen carbon atoms per molecule. Therefore, assigning kerosene as a mixture is correct.
Answer 5)
- It is an element. The molecular formula of oxygen is
. Which states that when found in diatomic state the oxygen is stable and can exist freely in nature. The elemental form of oxygen is in the diatomic form. Therefore, oxygen (
) is an element.