Semester 1 Chem Flashcards
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When do leading zeros count as significant figures?
They never count as significant figures
When do trailing zeros count as significant figures?
They are significant only is the number is written with a decimal point
How do you round off significant figures in addition and subtraction?
The numbers after the decimal place limit the answer to how many numbers that answer can have after the decimal place.
How do you round off significant figures in multiplication/division?
The smallest amount of significant figures in the numbers being multiplied limits the answer to how many significant figures it can have.
What makes up the atomic mass?
Neutrons and Protons
How is the atomic number found?
of protons
Do non metals or metals gain electrons?
Non metals
What are ionic compounds made up of? (Metals and/or nonmetals)
A metal and a non metal
What are covenant bonds made up of? ( metals and/or non metals)
2 or more non metals
What makes a substance pure?
Constant density
What makes a change chemical?
Anytime electrons are involved or when bonds break. Electricity, heat/decomposition reaction.
What makes a change physical?
Any distillation/ separating a mixture, boiling point (when substances are separated by different boiling points), density, mass
Combustion reaction?
Whine fuel combines with oxygen!
What happens in a single replacement reaction? (What replaces what?)
More reactive element replaces less reactive element
Double replacement? (Where are the aq and solid solutions?)
2 aqueous solutions combine to form a new aqueous and a new solid
Electronegativity
The ability to take electrons from another element
What defines the most reactive and lest reactive metal and non metal?
Non metals take electrons so the higher EN level the more reactive.
It is opposite for metals. Least EN level is most reactive.
When do you use hydro as prefix in front of acids?
When the element doesn’t have oxygen. Elements end in -ic.
When do you use -ous and when do you use -ic as a suffix for acids?
The acid will end in ic if the element has the correct amount of oxygens. When the acid lacks an oxygen molecule, the acid name ends in ous.
Are ionic or covenant bonds always written in empirical formula?
IONIC!!
For Charles law, where pressure is constant, what happens to the temp and volume when one changes?
Temp goes up, volume goes up
In Gay Lussac’s Law, where volume is constant, what happens to the pressure and volume when one changes?
Temperature goes up, pressure goes up? Not sure
What are the polarity/covalent numbers for electronegativity?
> 1.7 Ionic
.3-1.69 polar covalent
<.3 non polar covalent
What is the VSEPR theory?
Lone pair of electrons push elements to a bent position
