Chemistry Unit 2 - The Law of Conservation of Energy (Endothermic vs. Exothermic) & The Law of Conservation of Matter, Phases of Matter, Separating Mixtures

What can be used to separate a solvent from a solution?

Distillation

Define Enthalpy

another word for heat!

Define Chemical Reaction

A Chemical Reaction is a process that involves rearrangement of the molecular or ionic structure of a substance, as opposed to a change in physical form or a nuclear reaction.

Cold pack? Endothermic or exothermic?

An ice pack is Endothermic. The ice pack usually contains water and a packet of ammonium chloride. The cold pack is activated by breaking the barrier separating them and allowing them to mix. When the chemical ammonium nitrate is dissolved in water, the resulting solution is colder than either of the starting materials. The pack takes heat from the surroundings and becomes cold.

Combustion reaction (exo or endo thermic?)

Combustion is an oxidation reaction that produces heat, and it is therefore always EXOthermic.

What can be used to separate a solute from the solvent in a solution?

Evaporation

Evaporation (exo or endo thermic?)

Evaporation is ENDOthermic reaction because a liquid takes in heat from its surroundings to go from a liquid to a gas.

If the temperature increases (goes up), then you know it is an ________________________ reaction.

Exothermic

Ice melting (exo or endo thermic?)

Ice melting is an ENDOthermic reaction because thermal energy from the environment causes the molecules of solid water to vibrate fast enough to change to a liquid.

Describe molecules in a GAS (shape, movement)

In a gas, the molecules are separated by large distances, do not interact significantly with one another. The molecules shape is indefinite, volume is indefinite and they are compressible

Describe molecules in a LIQUID (shape, movement)

In a liquid, the molecules are closely spaced but free to move around and past each other. The molecule shape is indefinite, spacing close together and incompressible.

Describe molecules in a SOLID (shape, movement)

In a solid, the molecules are a rigid shape, vibrate around a fixed point. The molecule shape is definite, volume is definite and incompressible.

Describe Simple Distillation

In simple distillation, a mixture is heated and the most volatile component vaporizes at the lowest temperature., The vapor passes through a cooled tube (a condenser), where it condenses back into its liquid state. The condensate that is collected is called distillate.

What are the two basic forms of energy?

Kinetic energy and Potential energy

Define Kinetic Energy

Kinetic energy is the energy of motion

Is Electricity potential or kinetic energy?

Kinetic, electrical energy comes from the movement of electrons.

Mixing citric acid within baking soda (exo or endo thermic?)

Mixing citric acid within baking soda is ENDOthermic because it results in a cooler solution and causes a decrease in temperature.

Mixing water and potassium chloride (exo or endo thermic?)

Mixing water and potassium chloride is ENDOthermic because it results in a cooler solution.

Neutralization reaction (exo or endo thermic?)

Neutralization is an EXOthermic reaction because energy is released. A neutralization reaction is when an acid and a base react to form water and a salt.

What can be used to separate two liquids which are immiscible?

Separating Funnel

What can a magnet be used for in the separating process?

Separating a magnetic substance from a non-magnetic substance. Magnets are used in the recycling industry.

Snow forming inside clouds (exo or endo thermic?)

Snow forming inside clouds is EXOthermic. Snow is formed when temperatures drop low enough for water to change from a liquid to a solid, which is an exothermic process - as the surroundings cool, heat is transferred from liquid water into the surroundings, and the water solidifies into snow.

Any dissolving is (exo or endo thermic?)

The process of dissolving is exothermic when more energy is released when water molecules "bond" to the solute than is used to pull the solute apart. Because more energy is released than is used, the molecules of the solution move faster, making the temperature increase.

Define Thermal Energy

Thermal energy is the energy of heat. It is the kinetic energy of particles of matter. It is the heat caused by the friction of the molecules moving fast and bumping into each other. That's why it is kinetic.

Bond breaking is? (endothermic or exothermic?)

endothermic

Use of endothermic reactions

sports injury packs as the reaction allows pack to become instanly cooler without freezer reusable heat packs sodium ethanoate is crystalize by pressing and is spreadd throygh the solution it lasts a short time but is reusable

Burning candle (exo or endo thermic?)

Burning candle is EXOthermic. A candle flame is an exothermic reaction because when the candle burns it gives off heat.

Burning sugar (exo or endo thermic?)

Burning sugar is EXOthermic. Sugar is made of carbon, hydrogen and oxygen atoms. When heated over a candle, these elements react with the fire to turn into a liquid. The heat causes the sugar's atoms to combine with the oxygen in the air, forming new groups of atoms. Energy is released in this chemical reaction in the form of smoke and black soot.

Define chemical energy

Chemical energy is the energy that holds bonds between atoms together. This is potential energy because you don't get the energy until you break the bonds.

Describe how a car engine is an example of transforming chemical energy

Chemical potential energy in gasoline is transformed into kinetic energy of the car as it moves.

Define Chromotography

Chromotography is the separation of a mixture by passing it in solution or suspension or as a vapor through a medium in which the components move at different rates.

Define Nuclear Reaction

A nuclear reaction is a change in the identity or characteristics of an atomic nucleus that results when it is bombarded with an energetic particle, as in fission, fusion, or radioactive decay.

Define Reactants

Reactants are the substances that will be mixed

True or False? During physical and chemical changes, the total amount of matter remains constant.

TRUE

Freezing water into ice cubes (exo or endo thermic?)

Freezing water into ice cubes is EXOthermic. When the water is placed in a freezer, the water slowly loses heat to the surrounding cold air. The water molecules on losing energy begin to move slowly, come closer and pack close enough to change to ice.

Use of exothermic reactions

Hand warmers use the exothermic oxidation of iron in air (with a salt solution catalyst- NaCl) forming hydrated iron (iii) oxide to release energy -can only be used once but lasts a long time when activated

Hand warmers and self heating cans? Endothermic or exothermic?

Handwarmers are Exothermic. Air-activated hand warmers contain cellulose, iron, activated carbon, vermiculite (which holds water) and salt and produce heat from the exothermic oxidation of iron when exposed to air. Heat is produced in the surroundings. Heat Exits.

What is the Law of Conservation of Matter?

Matter cannot be created or destroyed; it can only change forms.

Define Mechanical Energy

Mechanical Energy is the total amount of potential and kinetic energy in a system. ME=PE+KE

Name 4 Types of Energy

Mechanical, Thermal, Electrical and Chemical

If the temperature decreases (goes down), then you know it is an ________________________ reaction.

endothermic (temperature

What is the Law of Conservation of Energy?

The law of conservation of energy states that energy cannot be created or destroyed. It can only be transformed.

Alcohol boils (exo or endo thermic?)

Water boiling is an ENDOthermic reaction. Water ABSORBS the heat from the burner on the stove.

Water boils (exo or endo thermic?)

Water boiling is an ENDOthermic reaction. Water ABSORBS the heat from the burner on the stove.

Water Freezes (exo or endo thermic?)

Water freezing is EXOthermic reaction because the item gets colder when heat is released.

Define Endothermic

With ENDOthermic, a system takes in energy from it's surroundings (outside source like a hot plate, the sun, a battery). It is a positive energy change because energy is gained.

Define Exothermic

With EXOthermic, a system releases (or EXits) energy to its surroundings (normally in the form of heat, but could be light or sound as well)..

Define Solubility

the ability of one substance to dissolve in another

ice pack (exo or endo thermic)

endothermic

Define Energy

what is needed to bond atoms and molecules together

What can be used to separate an insoluble substance from a soluble substance?

Filtration

Define Filtration

Filtration is a separation method used to separate out pure substances in mixtures comprised of particles some of which are large enough in size to be captured with a porous material. Filtration separates solids of different sizes.

Dissolving laundry detergent in water (exo or endo thermic?)

Dissolving of laundry detergent in water is EXOthermic because heat is released or Exits.

Define Distillation

Distillation is a purification process where the components of a liquid mixture are vaporized and then condensed and isolated. Distillation takes advantage of differences in boiling points

Name 4 techniques used to Separate Mixtures

Distillation, Evaporation, Filtration, Chromotography

Define Evaporation

Evaporation is the process by which liquid water becomes water vapor. Evaporation removes a liquid from a solution to leave a solid material. Or it is the process by which an element or compound transitions from its liquid state to its gaseous state below the temperature at which it boils; in particular, the process by which liquid water enters the atmosphere as water vapor. Example, table salt is obtained from the evaporation of seawater in many parts of the world.

glowstick (exo or endo thermic)

Exothermic because energy is released as fluorescent light. No heat energy is released in glow stick reactions..

Nuclear fission (exo or endo thermic?)

Nuclear fission is EXOthermic. Nuclear fission releases substantial amounts of energy.

Photosynthesis (exo or endo thermic?)

Photosynthesis is ENDOthermic reaction because it involves the input of the sun's energy into a chemical to make food for plants.

Define Potential Energy

Potential energy is stored energy.

Rain forming from water vapor in clouds (exo or endo thermic?)

Rain forming from water vapor in clouds is EXOthermic. The condensation of water vapor into rain releases energy in the form of heat so it is exothermic

Respiration (exo or endo thermic?)

Respiration is EXOthermic. Respiration is a series of exothermic reactions that occur in the mitochondria of living cells in order to release energy from food molecules. This energy can then be used to produce heat, for movement, growth, reproduction and other activities in the body.

Rusting of Iron (exo or endo thermic?)

Rusting of iron is an EXOthermic reaction because heat is released in the process.

What are the 3 Phases of Matter

Solid, Liquid and Gas

Steam condenses (exo or endo thermic?)

Steam Condensing is EXOthermic reaction because heat is released in the process. When you see a teapot with steam coming out, it will be hot on your hand if you put it near the steam entering the air.

Sublimation (exo or endo thermic?)

Sublimation is ENDOthermic because it requires energy to convert a solid into a gas. The atoms or molecules in a solid substance are tightly packed. In order to excite the atoms or molecules enough to turn into a gas, energy must be added, which makes sublimation an endothermic process. Sublimation is the transition of a substance directly from the solid phase to the gas phase without passing through the intermediate liquid phase

True or False? In a nuclear reaction, significant changes in mass can occur.

TRUE

True or False? Matter is neither created nor destroyed in a chemical reaction.

TRUE

Bond making is? (endothermic or exothermic?)

exothermic

change in enthalpy is negative

exothermic

Define Immiscible

incapable of being mixed

if change in heat is exothermic (positive or negative?)

it is negative

if energy change is endothermic (positive or negative?)

it is positive

Define Miscible

liquids that dissolve into one another, forming a new, single liquid.