science finale semester 2

which is a property shared by most molecular compounds

low melting points

when an action bosses an electron, it becomes

a positive ion

magnesium bromide is an ionic compound with chemical formulas MgBr2. what does the two tell you

there are two bromide ions for ever one magnesium ion

in the chemical formula for an ionic compound, which item is written first?

the name of the positive ion

the chemical name for the compound with the formula Na2S is

sodium sulfide

what is a double bond

two pairs of electrons shared between two atoms

electrons involved in bonding between atoms are

valence electrons

the columns in the periodic table are called

groups

which molecule has a polar bond

HF

which of the following groups contain the most reactive elements

the alkali metals

covalent bonds usually form when a non metal combines with a

non-metal

solid metals are good conductors of eat and

electricity

a ___ is a neutral group of atoms joined by covalent bonds

molecule

because the electrons in a molecule of hydrogen fluoride new more strongly pulled towards the fluorine atom, the molecule is

polar

in the periodic table, the number of valence electrons in each element _________ from left to eight across each period

increases

the properties of solid metals can be explained by the __structure__ of and the bonding among the metal atoms

true

orderly crystal shapes, high melting points, and electrical conductivity when dissolved in water are properties of __Ionic__ compounds

true

when electrons new __transferred__ between two atoms, a covalent bond is formed

shared/false

a low melting point is one property of __molecular__ compounds

true

a __non polar__ bond is formed when two atoms shared electrons unequally.

polar/false

list three elements from the group containing the most reactive nonmetals

fluorine, chlorine, and bromine

in an electron dot diagram of aluminum , how many dots show be drawn around the symbol. explain

there should be three dots around aluminum because it is in group 3a/13. there should also be three because aluminum has three valence electrons.

how many atoms of a group 17 element should be needed to react with one atom of group 2 element. explain

there should be 2 atoms form a groups 17 atom because when you transfer 1 valence electron from a group 2 atom, the group 17 atom would be stable. there group two atom would not be stable. there fore we must add 1 more group 17 atom to transferee there 1 valence electron from the group 2 atom. now all three atoms are stable.

water - ionic/covalent

covalent

HCN -ionic/covalent

covalent

Be + N - ionic/covalent

ionic

CS2 - ionic/covalent

covalent

NaCl - ionic/covalent

ionic

Al + Br

Ionic

Ba + F - ionic/covalent

ionic

CCl4 - ionic/covalent

covalent

sodium nitrate

NaNO3

lithium oxide

Li2O

magnesium sulfate

MgS

potassium bicarbonate

KHCO3

beryllium carbonate

BeCO3

sodium chloride

NaCl

CaSO4

calcium Sulfate

Na2O

sodium oxide

MgCO3

magnesium carbonate

speed = distance divided by

time

when you know both the speed and direction of an objects motion, you know the

velocity of the object

the steepness of a line on a graph is called the

slope

the rate at which velocity changes is call

acceleration

which pf the following is the SI unit for acceleration

m/s^2

on a graph showing distance verses time, a horizontal line represents an object that is

no moving at all

the International Systiem of Units is used by scientist

all over the world

an object changing direction is an example of

acceleration

which of these is an example. of deceleration

a car approchant a red light

if you know a car traveled 300 kilometers in three hours, you can find its

average speed

suppose you are siting in a car at. red light when a car is moving toward the north begins to pass you. if you are passing the car as a reference point, the direction in which you paper to be moving towards the

south

the basic SI unit for length is the

meter

a golf ball ______ when either it speeds up or direction changes

accelerates

if a car is speeding up, its initial speed is ____ than its final speed

less

if two lines appear on the same motion graph, ht Eline with the steeper ____ indicates a greater speed.

slope

if a toy car traveling at 10 cm/s asses a toy car moving at 10 cm/s in the opposite direction, both cares have the some __velocity__

speed/ false

motion is measured relative to a reference point

true

__Average speed__ is the rate at which am object is moving at a given instant

institanious speed/false

an SI unit of __velocity__ is the meter per second per second

acceleration/false

a strait diagonal line on a __distance-verses-time__ graph indicates constant speed

true

does the graph indicate that the ball decelerated? explain

the graph does not indicate that the ball is decorating because the line is rising not falling

what happened to the speed of the ball during the final two seconds

the speed of the ball in the last two seconds stay at a constant speed of 3 m/s.

what is the acceleration of the ball between 0 and 3 seconds

the acceleration is 1m/s2 between 0 and 3 seconds

a skater increases her velocity from 2.0 m/s to 10.0 m/s in 3.0 seconds. what is the skaters acceleration

pic

a truck traces down the highway at a speed of 110 km/hr. how lang does the trip last if the ruck covered 2200 km

pic

a car traveled 1027.88 km from Harrisburg, pA to Chicago, il in 11.75 hours. what was the average speed of the car

pic

at the circus, the human cannon ball is fired from its cannon at a speed of 350 m/s. how long does it take him to fly 200 m

pic

what is the acceleration

1\.5 km/h/s

what two variables are plotted on the graph

the two variables are time in minutes and distance in meters

how far did Kathy jog in the first four minutes

in the first 4 minutes, Kathy jogged 600 meters

describe the two joggers speed, is it constant, changing, instantaneous, how do you know

Kathy has a constant speed because she has a constant speed of 150 m/min. Rachle has a changing speeds ultimately leading to her stopping from minutes 7-10.