What are Physical Properties?
- Physical properties can be ___________________ and measured without changing the _______________ of the substance.
- _______________ Changes:
- _________________ Point: the temperature at which a substance ________ (or ___________…they’re just the reverse of each other, and it happens at the same temperature!). The freezing/melting point of water is _____ degrees C.
- __________ Point: the temperature at which a liquid boils (substances changes from a liquid to a ______). The boiling point of water is _____ degrees C.
- Different _________________ melt and boil at different ___________________, so we can use this to identify an unknown substance.
- Density: _________________________; how much mass is in a given amount of ____________ (volume). Every substance has a _____________ density that stays the same no matter how __________________________ the sample is, so we can use this to identify an unknown substance.
- Other physical properties: ____________, __________, color, smell, etc.
Phases of matter: Solids
- Solids: atoms are packed ______________ together in a rigid _______________. They still have some ___________, so they ______________ in place
Phases of matter: Liquids
- Liquid: at the ______________ point, atoms acquire enough energy to _____________ _____________; the pattern loosens up, and the substance can _____________
Phases of matter: Gases
- Gas: at the _____________ point, atoms have enough energy to change to a ________. In a gas the atoms or molecules move about _______________ and ________________ randomly with the walls of a container and with __________________________. The distance between molecules in a gas is much ______________ than that in a solid or a _________. (In a gas, the particles have LOTS of __________ and bounce off the walls!)
Phases of matter at the atomic level: Density
- As a substance goes from a ___________ to a liquid to a _________, the _____________ of the substance __________________. This is because as the pattern gets ___________, the atoms/molecules get ______________ apart.
- The exception is ___________: ice ____________ on liquid water, meaning ice (a solid) is __________ dense than water (a liquid)
Draw the Phases of Matter
What are Chemical Properties?
- Chemical properties can be observed only when substances ___________ or do not react _________________ with one another, that is, when they undergo a ______________ in composition. A ________________ property of one substance usually involves its ability to react or not react with another specific ___________________.
- Reacting with _______________: The ability of a substance to ____________ is a chemical property that involves a substance reacting _____________ with oxygen to produce light and heat (_________). Reacting with oxygen __________ occurs when iron _________.
- Reacting with an _________: some metals react with acids to form ____________, while ______________ solutions (we’ll talk about later) react with acids to form ________________ solutions.
Chemical Properties: Acids, Bases, and Neutral solutions
- Does it _______________ in water?
- Water is often called the “_____________________________________” because so many substances _______________________________ in it.
- Solutions can be ________________, basic, or _________________.
- Substances that form ____________ and _____________ must be dissolved in _____________ before you can tell if they’re acids or bases. Once dissolved in water, the substances release ___________.
- pH: a measure of how ____________ or basic a solution is.
- The pH scale goes from 1 to _______. A pH of _____ is a ______________ solution (neither an acid nor a base), a pH __________ than 7 is an _________, and a pH greater than _______ is a _____________.
Substances can Change
- Substances change in _____ ways:
- __________________ Change: a change that occurs that does not change the _________________ of the substance (it’s still the same “stuff”)
- ______________ change, ______________ change, change in size or shape, change in physical properties
- __________________ Change: a change that occurs that changes the ________________ of the substance (turns it into something else). Results in the formation of a _______________________________________.
- ______________ paper, digesting food, change in chemical properties
- When a chemical change occurs, it is called a chemical ____________
What is a Chemical Reaction?
- Chemical Reaction: when 2 or more substances _____________ (interact) to form a ___________ substance.
- Happens when substances (compounds or elements) ________________ (hit each other) and interact.
- In a chemical reaction, a ________________ change takes place (the substances you _______________ with become _________ substances).
- ________________ react to form _________________.
- Reactants: the substances you _____________ with
- Products: the substances you ___________ with
- Abbreviation for reaction: ___________
How do I know if a Chemical Change or Reaction has occurred?
- __________________ of a chemical reaction:
- ______________ Change
- Iron turns red-brown when it reacts with _________________ (rust)
- exceptions: food coloring or ________________ something
- ________________________ Change
- Wood __________________—increased temperature
- Exceptions: ______________ water, sunshine heating water in a lake
- Formation of a ______________
- ________________ form
- Exception: ________________ liquid
- Formation of a ________________________
- Precipitate: a _____________ that forms from combining 2 _________
What is a Reaction Rate?
- Reaction ___________: how _____________ it takes for the reaction to occur.
- Reactions occur at _________________ rates, from very __________ to very _____
- The reaction rate can be _________________ by:
- Changing the __________________________ of the reactants
- As concentration increases, reaction rate ___________________ (speeds up)
- Increase in concentration means more ________________ present that can react, leading to a ______________ and/or ______________ reaction.
- Changing the __________________ of the reaction mixture
- As temperature increases, reaction rate _________________
- Increased temperature makes the particles of a substance _______________ This increase in motion allows reactants to _____________ and interact more frequently (_________________ reaction rate).
- ___________________________ of the reactants
- Increased surface area=___________________ reaction rate
- If there’s more surface area, there’s more particles that can ______________ and interact
- Presence of a _________________
- Catalyst: something that _______________ a reaction, but is not ________________ in the reaction.