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8th grade chemistry

8th grade chemistry unit 8

QuestionAnswer
Physical Properties a property that can be observed without changing the identity of the substance
Physical Changes occurs when matter changes its property by not in a chemical nature: texture, shape,, size, color, odor, volume, mass, weight, density
Chemical properties the way a substance may change or react to form another substance-heat combustion, re-activity to water, pH, oxidation, flammability, re-activity to other chemicals
Chemical changes changes matter undergoes when it becomes new or different matter
Boiling point physical property- the point in which the property is from liquid to gas
Ability to rust chemical property- reacts with oxygen to produce rust
Melting point physical property- the point in which the property is liquid form from a solid or gas state
Brittleness physical property- the property where it can break without deforming or shredding the object
Reactivity with vinegar Chemical property- the ability to change the form of the property
elasticity physical property- the ability to be stretched or not
flammability Chemical property- the ability to burn
denisity physical property- the compactness of the substance
transparency physical property- the property of letting light pass through something
ductility physical property- the property to be able to be flatten
sublimation when anything solid turns into a gas with out being liquid first
combustible ability to catch fire and burn
what are the five indicators of chemical reaction emission of light or heat, formation of gas, formation of precipitate, color change, emission of odor
color change when the property change from gray to brown rust- ex rust
precicipitate a solid substance that forms as a result of reaction between chemicals in two liquid- ex. baking soda and vinegar
gas production when two substances are mixed and forms gas. ex antacid and stomach fluid
temperature change most reactions involve this. from a flame, or concrete before hardening ex. fireworks
change in characteristic properties are changed by light or odor. ex. light stick
what are the five types of chemical reactions synthesis, decomposition, single replacement, double replacement, combustion
synthesis two or more elements or compounds combine to make a more complex substance
synthesis example a + b -> AB
decomposition definition compound breaks down into simpler substance
decomposition example AB -> A + B
single replacement definition occurs when one element replaces another one in a compound
single replacement example AB + C -> AC + B
double replacement definition occurs when different atoms in two different compounds trade places
double replacement example AB + CD -> AC + BD
combustion definition one reactant is always oxygen and another reactant often contains carbon and hydrogen. the carbon and hydrogen atoms combine with oxygen, producing
combustion example C + O2-> CO2 + heat
what is the speed of reaction called Rate of reaction
What is Activation energy The minimum amount of energy needed for particles to react and is different for each reaction
What are 4 factors affect the rate of reaction Increase temperature increased concentration of dissolved reacts or pressure of gas in teased surface area use a catalyst
Why does a reaction proceed faster when the react ants have greater surface area more particles are available to collide and react when the surface area is greater Each time a large piece is broken, more surface area is exposed
Concentration A number of particles present in a certain volume. Higher means more can collide
Catalyst Is a substance that increases the rate of a chemical reaction without being consumed in the reaction
Inhibitor Is a substance that slows or prevents a reaction
Why must chemical reactions be balanced
To shine or not to shine what are the catalyst Salt acted as a catalyst to help speed up the chemical reaction
What does lower activation energy mean More coliseum between particles have sufficient energy to react
Why must chemical reactions be balanced The law of conservation says that matter is neither created nor destroyed during a chemical reaction so the number of atoms of each element must be the same on both sides of the equation
What are reactants Are the substance at the beginning of a he iCal reaction
Product The substance afterit is combined by a chemalreaction
What is a coefficient Indicates how many molecules take place in the reaction
If a chemical equation does not obey the law of conservation of mass the equation is said to be Not to balanced
Who was Afntoine Lavosier Scientist who came up with the law of conservation of mass helped construction of periodic table , named On and H
What is the law of conservation Mass is neither created nor destroyed during chemical reaction or physical reaction the bond between atoms in the reaction so all chemical equations must be balanced
What is bond energy The energy associated with bonds breaking
What is photosynthesis It is an endothermic reaction that absorbs energy from the sun to turn carvon dioxide and water into oxygen and glucose
Endothermic process A change (chemical reaction) that requires (or absorbs) heat, energy is taken in but not necessary given out
How can you determine if the reaction is endothermic The temperature of the reaction mixture decrease
Exeothermic process A change (a chemical reaction) that releases heat-energy is released as heat and light. More energy is given out than taken in
Example of Exothermic Burning fossil fuels, combustion, salt ando water
Examples of endothermic Photosynthesis, a edict acid and sodium,
Why were catalyst converters developed To help cars and trucks or machines move
What part of Silicon makes properties important in electronics 98%per
How is chemical reaction important in indusrty To make things move, light up, heat up, pick things up,machine things
Created by: Flynnfamily