science final exam (chem & electricity)

what is the difference between a mixture and a pure substance?

appear substance is made up of only one type of particle which can be atoms or molecules. A mixture contains two more different substances which can be elements and/or compounds that are physically combined, but not chemically bonded.

What is the difference between heterogeneous and homogeneous mixtures?

if a mixture consists of true particles, we have a homogeneous mixture, also known as a solution, it is uniform. If a mixture consists of things that are not true particles, we have a heterogeneous mixture also knows that known as a mechanical mixture. There is no dissolving, and there are bits that make up the mixture larger than actual molecules. It has non-uniform composition.

what is a solution?

when a substance is dissolved in another substance. In a solution, one substance (the solute) is dissolved in another (the solvent)

what is a physical change?

A physical change occurs when materials change, and there are no new materials with no new properties made.

what is a chemical change?

A chemical change occurs when materials change it to a new materials that have new properties

what are elements?

Appears substance made up of only one type of atom.

what are compounds?

A compound is pure substance made of two or more different element elements that are chemically bonded together.

how do objects become charged positively and negatively?

Positively charged objects have lost electrons and negatively charged objects have gained electrons.

what is the difference between ionic and covalent bonds?

Ionic bonds are formed by the transfer of electrons one atom loses electrons become positive and another gains electrons becomes negative covalent bond is formed by the sharing of electrons atoms, achieve stability by sharing electron pairs.

what happens to electrons when covalent bonds are formed?

electrons are shared between the elements involved in the bond

what is the difference between families and periods on the periodic table?

periods are from top to bottom (horizontal) families are from side to the other side (vertical)

what is an isotope?

isotopes is a form of an element that has the same number of protons but a different number of neutrons in its nucleus.

what is the pattern of reactivity of elements on the periodic table?

The more left or right, excluding the noble gases group 18 the more reactive. The elements are also the higher up lower period numbers the more reactive the elements are.

what conditions are needed for the best chance of static discharge to occur?

dry air

how does induction charge objects?

Charging object without touching induction is a method of charging an object without direct contact. Instead, it uses the presence of a charge object to rearrange electrons in a nearby neutral object.

how does conduction charge objects

charging by direct contact conduction is a method of charging an object by touching it with another object during this process electrons are transferred from one object to another.

what is power?

Power is how fast energy is changed into useful energy. It’s measured in watts (1 W = 1 joule pee second) the more electrical energy converted to useful energy the more efficient the machine some energy will always be lost as heat therefore no machine is 100% efficient.

what is voltage?

Also called potential difference or electromotive force it’s a measure of how much charge separation there is more separation means more capacity to do work. It is measured in volts the higher, the voltage, the greater the potential difference and the more energy. The current can supply so a 9 V battery will make a small lightbulb glow much brighter than a AA battery.

what is current?

when electric charges move, they create an electric current electric current is measured by the amount of charge that flows by a certain point every second

what unit measures energy, power and time?

Energy unit is joules (J) power unit is watts (W) what time unit is seconds (s)

how do you calculate power energy, and time using the formula for power?

Power = energy / time

Time = energy / power

Energy = power x time

what is an electrical Circuit and what parts must they have?

It must have a power source, conductive path and a load many circuits also have a switch, but they are not Necessary.

what is a parallel circuit?

A parallel circuit is collected in such a way that there are multiple paths for electricity to flow

what is a series circuit?

A series circuit is connected in such a way that there is a single path for electricity to flow (not counting a switch in direction)