Post by P.Q. on Mar 17, 2012 5:37:44 GMT -7
The atomic number of an atom is:
is:
the number of protons in the nucleus
The phase of matter that has a defined volume, but not a defined shape is:
is:
liquid
The structure of an atom is best described as:
is:
electrons in orbit about a nucleus of protons and neutrons
Which is always a characteristic of a chemical change, but not always a characteristic of a physical change?
is:
making a new substance
An ionic bond differs from a covalent bond in that: in an ionic bond, one or more electrons transfer from one atom to another; while in a covalent bond, one or more electrons is shared by two atoms
Which reaction cannot proceed without an activation energy?
is:
starting a fire
C2H4 =hydrocarbon AKA Carbon2Hydro4
In the chemical formula 3H2O, how many atoms are there of each element?
6 hydrogen and 3 oxygen (It's because 3 is the oxygen and you have to add hydrogen by 3!) 3+3 = 2
How is the reaction 2H2 + O2 -> 2H2O described in words?
two molecules of hydrogen combine with two molecules of oxygen to form two molecules of water
This is because the 2 before the H Is not lower case 2.
The overall reaction for photosynthesis is: 6CO2 + 12H2O + light -> C6H12O6 + 6O2 + 6H2O. Which of the following statements is true?
The number of atoms on each side of the equation is the same.
chemical equation - name given to the shorthand used to describe the steps of a chemical reaction
reactants - the starting materials for a chemical reaction; the substances that combine in the reaction
products - the substances that are formed as a result of a chemical reaction
chemical reaction rate - the speed at which a chemical reaction occurs
activation energy - the external energy that has to be added in order for a chemical reaction to occcur
catalyst - a substance that helps a chemical reaction to occur (lowers the activation energy), but does not participate in the reaction itself
Law of Conservation of Mass - this Law states that matter is neither created nor destroyed in a chemical reaction. The number of reactant atoms of a chemical reaction will be the same as the number of product atoms.
Solid - a solid has a definite shape and volume
Liquid - a liquid has a definite volume, but can change shape
Gas - the shape and volume of a gas can change
Phase Changes
These phases of matter can change from one to another. Remember the definitions of the following phase changes:
Melting - melting occurs when a substance changes from a solid to a liquid
Boiling - boiling is when a substance changes from a liquid to a gas
Condensing - condensation is when a gas changes to a liquid
Freezing - freezing is when a liquid changes to a solid
Physical & Chemical Changes
The changes that take place in substances may be categorized in two classes:
Physical Change - does not produce a new substance (e.g., phase changes, crushing a can)
Chemical Change - produces a new substance (e.g., burning, rusting, photosynthesis)
Solutions
A solution results from combining two or more substances. Making a solution can produce either a physical or chemical change. You can tell them apart this way:
The original substances can be separated from one another if the solution produces only a physical change.
The original substances cannot be separated from one another if a chemical change took place.
Hydrocarbons - molecules that only contain the elements carbon and hydrogen (e.g., CH4 is a hydrocarbon while CO2 is not)
Organic - refers to the chemistry of living things, all of which contain the element carbon
Organic Chemistry - study of the chemistry of carbon compounds involved in life (so, studying diamond, which is a crystalline form of carbon, isn't included in organic chemistry, but studying how methane is produced is covered by organic chemistry)
Organic Molecules - molecules that have carbon atoms linked together in a straight line (carbon chain) or in a circular ring (carbon ring)
Polymer - hydrocarbons which have chained together
is:
the number of protons in the nucleus
The phase of matter that has a defined volume, but not a defined shape is:
is:
liquid
The structure of an atom is best described as:
is:
electrons in orbit about a nucleus of protons and neutrons
Which is always a characteristic of a chemical change, but not always a characteristic of a physical change?
is:
making a new substance
An ionic bond differs from a covalent bond in that: in an ionic bond, one or more electrons transfer from one atom to another; while in a covalent bond, one or more electrons is shared by two atoms
Which reaction cannot proceed without an activation energy?
is:
starting a fire
C2H4 =hydrocarbon AKA Carbon2Hydro4
In the chemical formula 3H2O, how many atoms are there of each element?
6 hydrogen and 3 oxygen (It's because 3 is the oxygen and you have to add hydrogen by 3!) 3+3 = 2
How is the reaction 2H2 + O2 -> 2H2O described in words?
two molecules of hydrogen combine with two molecules of oxygen to form two molecules of water
This is because the 2 before the H Is not lower case 2.
The overall reaction for photosynthesis is: 6CO2 + 12H2O + light -> C6H12O6 + 6O2 + 6H2O. Which of the following statements is true?
The number of atoms on each side of the equation is the same.
chemical equation - name given to the shorthand used to describe the steps of a chemical reaction
reactants - the starting materials for a chemical reaction; the substances that combine in the reaction
products - the substances that are formed as a result of a chemical reaction
chemical reaction rate - the speed at which a chemical reaction occurs
activation energy - the external energy that has to be added in order for a chemical reaction to occcur
catalyst - a substance that helps a chemical reaction to occur (lowers the activation energy), but does not participate in the reaction itself
Law of Conservation of Mass - this Law states that matter is neither created nor destroyed in a chemical reaction. The number of reactant atoms of a chemical reaction will be the same as the number of product atoms.
Solid - a solid has a definite shape and volume
Liquid - a liquid has a definite volume, but can change shape
Gas - the shape and volume of a gas can change
Phase Changes
These phases of matter can change from one to another. Remember the definitions of the following phase changes:
Melting - melting occurs when a substance changes from a solid to a liquid
Boiling - boiling is when a substance changes from a liquid to a gas
Condensing - condensation is when a gas changes to a liquid
Freezing - freezing is when a liquid changes to a solid
Physical & Chemical Changes
The changes that take place in substances may be categorized in two classes:
Physical Change - does not produce a new substance (e.g., phase changes, crushing a can)
Chemical Change - produces a new substance (e.g., burning, rusting, photosynthesis)
Solutions
A solution results from combining two or more substances. Making a solution can produce either a physical or chemical change. You can tell them apart this way:
The original substances can be separated from one another if the solution produces only a physical change.
The original substances cannot be separated from one another if a chemical change took place.
Hydrocarbons - molecules that only contain the elements carbon and hydrogen (e.g., CH4 is a hydrocarbon while CO2 is not)
Organic - refers to the chemistry of living things, all of which contain the element carbon
Organic Chemistry - study of the chemistry of carbon compounds involved in life (so, studying diamond, which is a crystalline form of carbon, isn't included in organic chemistry, but studying how methane is produced is covered by organic chemistry)
Organic Molecules - molecules that have carbon atoms linked together in a straight line (carbon chain) or in a circular ring (carbon ring)
Polymer - hydrocarbons which have chained together