Identify the pure substances in the list. If there is more than one, select all the apply.
a) gold (Au)
b) Air (mostly N2 and O2)
c) white blood
d) saline solution
e) alcoholic drink
f) ethanol (CH3CH2OH)
g) elemental oxygen
h) table salt (NaCl)
What is your trouble with this? If they are elements they are pure. If mixtures or compounds they are not.
I will get you started.
a. Gold is an element. Pure.
b. air (mixture N2 and O2 and other gases). not pure.
c. white blood (you must mean white blood cells (consists of compounds). not pure.
d. saline solution. That's a mixture of salt and water. not pure.
etc
etc.
To identify the pure substances in the given list, we need to understand what a pure substance is. A pure substance is a type of matter that has a fixed chemical composition and specific properties. It can either be an element or a compound.
Let's analyze each option:
a) Gold (Au): Gold is an element, which means it is a pure substance.
b) Air (mostly N2 and O2): Air is a mixture of gases, primarily nitrogen (N2) and oxygen (O2). It is not a pure substance because it contains different types of particles.
c) White blood: White blood is not specific enough to determine if it is a pure substance. Without additional information, we cannot say for sure.
d) Saline solution: A saline solution is a mixture of water and salt (NaCl). Therefore, it is not a pure substance.
e) Alcoholic drink: An alcoholic drink is a mixture of various compounds, including ethanol (CH3CH2OH) and other substances. It is not a pure substance.
f) Ethanol (CH3CH2OH): Ethanol is a compound and, therefore, a pure substance.
g) Elemental oxygen: Elemental oxygen refers to oxygen that exists as individual atoms (O2). It is an element and a pure substance.
h) Table salt (NaCl): Table salt is a compound composed of sodium (Na) and chloride (Cl). While it is a pure substance, it is not an element.
Based on this analysis, the pure substances in the list are:
a) Gold (Au)
f) Ethanol (CH3CH2OH)
g) Elemental oxygen (O2)
h) Table salt (NaCl)