Chemical Reactions Quiz Flashcards
what does aq in brackets mean
it dissolves in water and its in a solution
what is the law of conservation of mass
states that matter cannot be created nor destroyed, and can only change forms
what makes up a reaction system
reactants and products
what does the total mass of reactants equal
total mass of products
what is the purpose of coefficients in skeleton equations
makes sure law of conservation of mass is obeyed
what do the coefficients tell you in a skeleton equation
the total amount of those molecules in the reaction
what is the difference between the coefficient and subscript in a skeleton equation
subscript tells you how many of each atom are in the compound, coefficient tells you how many of the molecule/compounds are in the reaction
what do you have to make sure of when balancing a chemical equation
that you have the same amount of each individual element on both sides of the equation
how do you find how many of each individual element you have in the reaction
multiply the coefficient by the subscript
what splits the different elements or compounds that are not combined into one in the reactant state
a plus sign
what are the general rules of balancing
- balance atoms/ions you have the most of first
- coefficient always goes at the beginning of the compound
- no fractions
- always have coefficients in the lowest whole number ratios
- balance combustion reactions in alphabetical order based on the chemicals, with oxygen always being last
how can you use nomenclature when writing balanced chemical reactions
to identify ionic, molecular and acidic compounds
how can the solubility table help you when writing balanced chemical reactions
to predict aqueous or solid for ionic compounds reacting in water
how do reaction types help you write balanced chemical reactions
allows you to predict products
what is the purpose of balancing chemical equations
to obey the law of conservation of mass
how do you determine the state of a product if it is ionic
- assume it is solid as a pure substance
- if part of a reaction in water, use solubility table
- reactants are aqueous
how do you determine the state of a product if it is molecular
- use any info from question and databook
- never assume state (if it doesn’t tell you what it is, then just done include state)
what are molecular elements
elements that always exist as molecular atoms and are never found on their own
what are some examples of chemical reactions around us
fireworks, glowsticks, airbags, adhesives, hadnwarmers
what are two examples of chemical reactions in the natural world
photosynthesis and cellular respiration
what are the two ways to show a chemical reaciton
word equation or skeleton equation
how do you read reaction equations
everything on the left of the arrow is the reactants, everything on the right of the arrow is the products
whats a chemical reaction
involves rearranging of atoms to create new substances and is usually irreversible
what is some evidence of chemical change
temperature increase, emission of light or sound, production of electrical energy, decrease in temperature, production of nan odour, colour change, formation of gas, bubbles, formation of precipitate
what are the different types of chemical reactions
formation, decomposition, single replacement, double replacement, combustion
whats a formation reaction
when two or more elements or two or more simple compounds react to produce one compound or one more complex compound
whats a decomposition reaction
when one compound decomposes to produce its constituent elements or to form a simpler substance
whats a single replacement reaction
when an element reacts with compound to produce a different compound and a different element
what replaces what in a single replacement reaction
the metal will always replace the metal in the compound or the non-metal will always replace the non-metal in the compound
whats a double replacement reaction
when two compounds react to produce two different compounds
why will cations or anions never combine
because they are the same charge and will repel each other
where are anions written in a chemical formula
second
whats a combustion reaction
a compound or element reacting with oxygen to produce oxides of the elements in the reactant
what are the by-products of complete combustion
water and carbon dioxide
whats hydrocarbon combustion
any sort of hydrocarbon reacting with oxygen
whats hydrocarbon
any combination of hydrogen and carbon
when does complete combustion occur
when carbon and hydrogen react with oxygen
how do you predict a decomposition reaction
if you see one reactant
how do you predict double replacement
when there are two ionic compounds reacting with each other
how do you predict complete combustion
when you see a hydrocarbon reacting with oxygen
how do you predict combustion
when you see anything reacting with oxygen
how do you predict single replacement
when you see one element on its own reacting with a compound
how do you predict formation
if you see just two elements reacting with each other
