Physical Change
What is a physical change?
A change in a substance that does not involve a change in the identity of the substance - solid to liquid to gas.
What is a chemical change?
A change in matter that produces one or more new substances.
What's a chemical reaction?
The process by which one or more substances change to produce one or more different substances.
What's a covalent bond?
Results from the sharing of electron pairs between two atoms.
What are valence electrons?
Electrons on the outermost energy level of an atom.
What physical change could have taken place if the ice cubes in your drink melted?
Answer: Melting
What is combustion?
A substance reacts with oxygen from the air and transfers energy to the surroundings as light and heat.
What is a reactant?
A reactant is a chemical substance that is seen at the start of a chemical reaction.
Is hydrogen a covalent bond?
Answer: Yes
How many valence electrons does fluorine have?
Answer: 7
What are three types of physical changes?
Possible Answers: Boiling, clouding, dissolution, freezing, freeze-drying, frost, liquefaction, melting, smoke, and vaporization.
What is flammability?
The ability of a chemical to burn or ignite, causing fire.
What is an endothermic reaction?
A reaction that absorbs energy in the form of heat and the temperature increases.
True or False: Sodium Chloride is a covalent bond.
Answer: False! It is a ionic bond.
How many valence electrons does nitrogen have?
Answer: 5
Which one is a physical change: Cutting or Density?
Answer: Cutting
True or False: Rusting is a type of chemical change.
Answer: True
What is an exothermic reaction?
A reaction that releases energy in the form of heat and the temperature decreases.
How many electrons can be shared in a covalent bond?
Answer: Two electrons
How many valence electrons does carbon have?
Answer: 4
What's the difference between a physical change and a chemical change?
The difference between the two is that in a physical change the appearance or form of the matter changes but the kind of matter in the substance does not, but in a chemical change the kind of matter changes, and at least one new substance with new properties is formed.
What is the difference between combustibility and flammability?
A combustible material ignites with some effort and a flammable material catches fire immediately on exposure to flame.
What's decomposition?
A chemical reaction that breaks down compounds into simpler products.
What is the difference between a covalent and ionic bond?
The difference between the two are that one atom essentially donates an electron to another atom in an ionic bond while electrons are shared between atoms in a covalent bond.
How many valence electrons does oxygen have?
Answer: 6