Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
21 Cards in this Set
- Front
- Back
|
What are the two properties that describe matter?
|
Chemical and physical properties describe matter.
|
|
|
What are the two kinds of changes that matter can undergo?
|
Matter can undergo both chemical and physical changes.
|
|
|
What is a physical property? Know examples.
|
A physical property would be overall appearance including color, texture, odor, etc., and this would also include the state of matter—solid, liquid, or gas.
|
|
|
What is a chemical property? Know examples.
|
A chemical property refers to the reactivity of a substance. Reactivity determines how much a substance will react or combine with other substances.
|
|
|
What is a physical change?
|
A physical change would be any change in a physical property.
|
|
|
What is a chemical reaction? Give an example.
|
Chemical reactions occur when bonds break and new bonds form. An example is oxygen gas and hydrogen gas forming water. You can think of millions of other examples, I’m sure ☺ Just remember that a chemical change will always create a new substance and involve a change in energy.
|
|
|
When do chemical changes occur?
|
Chemical reactions occur when bonds break and new bonds form.
|
|
|
Describe chemical changes in terms of the two kinds of chemical reactions we have studied: ionic and covalent.
|
We have studied ionic reactions and covalent reactions. Remember that ionic bonds form between cations and anions made from metals and nonmetals. These bonds are very strong because of the opposite charges holding them together.
|
|
|
What are three evidences of chemical reactions?
|
Covalent bonds form between two nonmetals that share electrons. These bonds are much weaker.
|
|
|
What is a precipitate?
|
A change in substance and a change in energy are the two primary changes. Other changes can include color changes, precipitate formation, and/or gas production. Remember that every chemical reaction will have a change in substance (something new is made) and energy is always released or absorbed (even if you don’t feel it).
|
|
|
Review labs we have done where precipitates have formed. What kinds of changes did you observe in these reactions?
|
A precipitate is a solid that is formed when some chemicals react. The ones we have looked at are liquids combining to form a solid. Here is an example:
2NaOH + CuSO4 ⇒ Na2SO4 + Cu(OH)2 This reaction combines sodium hydroxide and copper sulfate as the reactants to produce sodium sulfate (liquid) and copper hydroxide (precipitate). |
|
|
What is the difference in exothermic and endothermic reactions? Understand energy differences.
|
Exothermic reactions are reactions in which energy is given off in the form of heat, usually. Endothermic reactions are those that absorb heat from the surroundings. Sometimes they feel cold, but in the case of cooking an egg or baking a cake, heat is being absorbed but you will not feel cold.
|
|
|
What is a chemical equation?
|
A chemical equation is reactants combining to produce products. Ex. 2H2 + O2 → 2H2O
|
|
|
What principle does a balanced chemical equation represent?
|
A balanced equation represents the conservation of mass.
|
|
|
Describe the conversation of mass principle in your own words.
|
The principle of conservation of mass states that matter is neither created nor destroyed in a chemical reaction.
|
|
|
What is a formula? Give a few examples.
|
A formula is chemical symbols and numbers that represent a compound or molecule. Ex. H2O is the chemical formula for water.
|
|
|
What is the structure of a chemical equation?
|
The structure of a chemical equation is:
reactant + reactant → product + product |
|
|
What is the difference between reactants and products?
|
Reactants combine to produce products.
|
|
|
What is the difference between an open system and a closed system?
|
An open system is one in which substances can enter or leave during a chemical reaction. A closed system is one in which nothing can enter and nothing can leave during a chemical reaction.
|
|
|
In which system is the conservation of mass represented and why?
|
Conservation of mass is represented in both open and closed systems since matter is neither created nor destroyed in a chemical reaction, even if it cannot be measured.
|
|
|
What are the five kinds of chemical reactions we have studied?
|
The five types of reactions we have concentrated on are synthesis, decomposition, combustion, single replacement, and double replacement reactions. Combustion reaction is one in which oxygen (O2) is one of the reactants.
|
