Elements vs Compounds
This is a pure substance made of only one kind of atom. Give an example.
What is an element. Ex: Gold, Oxygen, Hydrogen, etc.
What does the chemical symbol on the periodic table represent? Give an example.
A symbol is a 1–2 letter abbreviation for an element (e.g., O = oxygen)
In the chemical formula H2O, how many hydrogen atoms are in one molecule?
2
If you have 4H2O, how many molecules do you have?
4
For H2O, what is the total number of atoms in one molecule?
3 (2+1)
This type of pure substance is made of two or more different elements chemically combined in a fixed ratio. Give an example.
What is a compound. EX: salt (NaCl), water (H2O)
How many elements are known on the periodic table?
118
How many oxygen atoms are present in 3 molecules of CO2?
6 (3*2)
You are given 6CO2. How many molecules of CO2 are present?
6
For 3Na2SO4, find the total number of atoms and show how you calculated it
Total: 21
7*3 or 6+3+12
Is H2 a single element or a compound? Explain using atoms and molecules language.
It is an element because it is made up of one type of atom (hydrogen) even though it has 2 atoms, they are the same element.
Who is credited with organizing the current periodic table of elements? Element 101 is named after him.
Dmitri Mendeleev
For Al2(SO4)3, how many sulfur atoms are in one formula unit?
3
If a sample contains 5 molecules of CH4, how many carbon atoms are in that sample?
5
4Fe(NO3)3 . Calculate the total number of atoms.
52
13*4 or 4+12+36
Compare the smallest particle of an element and the smallest particle of a compound
Smallest particle of an element is an atom, but the smallest particle of a compound is a molecule because it is at least 2 atoms chemically bonded.
Using the periodic table, what does the atomic number tell you about an atom? Give an example.
Atomic number = number of protons (Oxygen is #8 because it has 8 protons)
For Al2(SO4)3, calculate the total number of oxygen atoms in one formula unit
12 (4*3)
If a student has 8 molecules of NH3, how many hydrogen atoms are present?
24 (8*3)
4K2CO3
What are the total atoms for EACH element?
K=8 (4*2)
C=4 (4*1)
O=12 (4*3)
A sample contains only molecules that are each made of two different elements chemically bonded. Is the sample an element, compound, or mixture?
What is a compound.
Explain how the periodic table can help you determine the identity and number of different atoms in the formula C2H5OH (ethanol)
The periodic table can help you identify the elements in the formula (C=Carbon, H=Hydrogen, O=Oxygen) and then the subscripts can help you identify the number of atoms
How many atoms of hydrogen are in this formula: CH3COOH?
4 (3+1)
A container holds 7C6H12O6 (glucose). How many molecules of glucose are there, and how many hydrogen atoms are in the container total?
Molecules=7
Hydrogen= 84 atoms
Breakdown how many Elements, Molecules, and Total Atoms there are
Elements=4 (Na, H, C, O)
Molecules=3
Total Atoms: 18 (6*3 or 3+3+3+9)