Elements
Elements, Compounds, and Mixtures
Atomic Molecular Theory
Relative Masses and the Mole
Math
100
What are the symbols for hydrogen, nitrogen, oxygen, and carbon?
H, N, O, and C
100
What is air?
A mixture
100
What is the Law of Combining Volumes?
"when gases combine during a chemical reaction at a fixed pressure and temperature, the ratios of their volumes are simple whole number ratios" -Atomic Molecular Theory in class notes
100
What is a mole?
The mass of substance containing the same number of units as there are atoms in exactly 12.000 g of Carbon 1 mole, for an atom, is its atomic mass. Every mole has the same number of particles as other moles.
100
Calculate the number of moles in 72.5g of neon.
20.18g Ne/1mol Ne = 72.5g Ne/x mol Ne =3.59mol Ne
200
What is the symbol for molybdenum?
Mo
200
What is the difference between a pure substance and a mixture?
A pure substance is a group of the same compounds or elements A mixture is a group of different elements, compounds or both
200
What is Avogadro's Hypothesis?
Equal volumes of two gases at the same temperature and pressure contain equal numbers of molecules.
200
What is the molecular mass of CO2?
44.01 (12.01+16+16)
200
If there is 79.89% of Copper 20.11% of oxygen in a copper oxide, how much copper and hydrogen is there in a 63.00g sample of the same substance.
50.33g Cu 12.67g O
300
How can you identify hydrogen gas and oxygen gas?
Oxygen ignites when it comes in contact with a lit match Hydrogen pops when it comes in contact with a lit match
300
What are elements, molecules, and compounds?
An element is formed by only one kind of atom; it can be multiple of the same atoms bonded together (molecule) or as an individual atom. A molecule is two or more atoms of the same element bonded together. A compound is a particle of two or more different elements bonded together
300
Draw a particle diagram of 3 liters of hydrogen combining with 1 liter of nitrogen to create 2 liters of ammonia.
(check with group)
300
If you have 4.00g of tungsten and 4.00g of carbon, do you have the same amount of particles? Explain.
No; it would take more moles of carbon to weigh 4.00g because it has a smaller relative mass than tungsten.
300
Sulfur and oxygen form both sulfur dioxide and sulfur trioxide. When samples of these were decomposed the sulfur dioxide produced 3.49 g oxygen and 3.50 g sulfur, while the sulfur trioxide produced 6.75 g oxygen and 4.50 g sulfur. Calculate the mass of oxygen per gram of sulfur for each sample and show that these results are consistent with the law of multiple proportions. (#37 from the TB)
Sulfur Dioxide (SO2)- 1gO:1gS Sulfur Trioxide (SO3)- 1.5gO:1gS 1gO (SO2): 1.5gO (SO3) ---> 2:3 It satisfies the law of multiple proportions because there is a whole number ratio when the oxygen and sulfur combine
400
Name all diatomic particles
Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, and Fluorine (Br2I2N2Cl2H2O2F2)
400
Which of the following terms can be used to used to describe C6H12O6? (both 6s and 12 are subscripts) Element, Compound, Mixture, Pure Substance, Molecule
Compound, Pure Substance, and Molecule (question was slightly edited, but it is from the Atomic Molecular Theory quiz)
400
What is the Law of Definite Proportions? What is the Law of Multiple Proportions?
The Law of Definite Proportions states that "when two or more elements combine to form a compound, their masses are in a fixed and definite ratio" (-the Atomic Molecular Theory in class notes). For example, in carbon dioxide there is always the same percent of carbon and oxygen in a sample The Law of Multiple Proportions states that "when two elements combine to form more than one compound, the mass of element A in one compound has a simple whole number ratio with the mass of element A in another compound for a given mass of element B" (-The Atomic Molecular Theory in class notes). In other words, if you have two or more substances with the same elements in them, you can set one of the elements equal to 1g (like 1g of carbon for example) to see how much of the other element is there per that 1g. There should be a whole number ratio of the element that you didn't set equal to one.
400
How many moles of molecules are there in 5.00g of nitrogen gas?
.178mol N (nitrogen gas is N2- if you got .357, you forgot to double the relative mass of nitrogen for 1 mole of N2)
400
Phosphorus creates two compounds with chlorine. In the first compound, 1.000g of phosphorus is combined with 3.433g chlorine. In a second compound, 2.500g of phosphorus is combined with 14.306g of chlorine. Show that these results are consistent with the law of multiple proportions.
5g Cl (B): 3g Cl (A) it is consistent with the law of multiple proportions because chlorine combines with 1g of phosphorus in a whole number ratio.
500
Sb, At, Ac, and Sr
What is antimony, astatine, actinium, and strontium?
500
In 3C6H12O6 how many carbon, hydrogen, and oxygen atoms are there in total? How many total compounds are there? How many unique compounds are there? Is this a pure substance?
18 Carbon atoms; 36 Hydrogen atoms; 18 Oxygen atoms. 3 total compounds; 1 unique compound This is a pure substance
500
3 compounds are formed when nitrogen combines with oxygen. Compound A has a mass of 1.750g of nitrogen when it combines with 1g of oxygen; compound B has a mass of .8750g of nitrogen when it combines with 1g of oxygen; compound C has a mass of .4375g of nitrogen when it combines with 1g of oxygen. If compound B is NO, what is the chemical formula of the other compounds?
Compound A- N20 Compound C- NO2
500
Does 78.97g of Se have the same number of particles as 12g of C? Explain.
yes because 78.97g of Se is one mole of Se; 12g is one mole of C. Moles have the same number of particles.
500
Methane is a compound composed of carbon and hydrogen. Analysis of a 15.00g sample shows that it contains 11.22g of carbon and 3.78 3.78g of hydrogen. a) calculate the percent composition by mass of carbon and hydrogen in methane. b) Calculate the mass of carbon that could be recovered from 50.0g of methane. c) Analysis of a 25.0 g sample of an unknown hydrocarbon shows that it contains 19.97g of carbon and 5.03g of hydrogen. Is the unknown compound methane? Justify ~this question is taken directly from the Atomic Molecular Theory quiz~
a) 74.8%C and 25.2%H b) 37.4g C in 50.0g of methane c) 79.89%C and 20.11% H; no it is not methane because there is not the same proportion (percent) of carbon and hydrogen in the substance as there is in methane.
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