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For the 9th grade MPCS science final

A substance that is made up of only one kind of atom is an

element

Which of the following statements about ice melting is true?

water molecules move from their fixed positions

the phase change in which a substance changes from a solid to a liquid is

melting

the phase change in which a substance change from a solid to a gas or vapor without changing to a liquid first is

sublimation

which of the following phase changes is an endothermic change

vaporization

which of the following phase changes is an exothermic change

deposition

the Greek philosopher Democritus coined what word for a tiny piece of matter that cannot be divided

atom

J.J. Thomson's experiments provided evidence that an atom

contains negatively charged particles

The number of protons in one atom of an element is that element's

atomic number

to find the number of neutrons in an atom, you would subtract

atomic number from the mass number

Which statement is true about oxygen-17 and oxygen-18

they are isotopes of oxygen

what can you assume has happened if an electron moves to a higher energy level?

the electron has gained energy

which statement accurately represents the arrangement of electrons in Bohr's atomic model

electrons travel around the nucleus in fixed energy levels with energies that vary from level to level

what does the electron cloud model describe

the most likely locations of electrons in atoms

which statement about electrons and atomic orbitals is true?

an electron cloud represents all the orbitals in an atom

the glowing of a neon light is caused by electrons emitting energy as they

move from higher to lower energy levels

mendelev arranged the known chemical elements in a table according to increasing

mass

which statement is true about the metalloid silicon

silicon is a better conductor of an electric current than sulfur is

at room temperature none of the metals are

gases

atoms of the most reactive elements tend to have

one or seven electrons

an alkali metal has one valence electron, while an alkaline earth metal has

two

among the alkali metals, the tendency to react with other substances

increases from top to bottom within the group

which of the following gases emit colors when an electric current is applied

helium and neon

to keep them from reacting, some highly reactive elements are stored in

argon

the formation of an ionic bond involves the

transfer of electrons

which of the following statements correctly describes the substance with the formula KI

there is a one-to-one ratio of potassium ions to iodide ions

in the compound MgCl2, the subscript 2 indicates that

there are two chloride ions for each magnesium ion

the water molecule H2O is polar because it contains two polar single bonds and

its molecule has a bent shape

water has a higher boiling point than expected because

of the strong attractions between polar water molecules

the elements most likely to form more than one type of ion are the

transition metals

beryllium, Be, and chlorine, Cl, form a binary ionic compound with a one-to-two ratio of beryllium ions to chloride ions. the formula is

...

a force acting on an object does no work if

the force is not in the direction of the object's motion

if you exert a force of 10 N to lift a box a distance of .75m, how much work do you do?

7.5J

the SI unit of power is the

Watt

a machine is a device that can multiply

force

how can you make the work output of a machine greater than the work input?

you can't!

reducing friction in a machine

increases its efficiency

a mechanical device requires 400J of work to do 340J of work in lifting a crate. What is the efficiency of the device?

85%

an inclined plane reduces the effort force by

increasing the distance over which the force is applied

an ax is an example of a

wedge

the ideal mechanical advantage of a pulley system is equal to the

number of rope segments supporting the load

an example of a compound machine is a

bicycle

an element has a fixed composition because it contains only one type of

atom

the symbol for elements have either ____ or ___ letters

one/two

in a ________ mixture, the parts of the mixture are noticeably different from one another

heterogeneous

if a spoon gets hot quickly when it is used to stir a pot of soup, it is probably made of

metal

_____ is a process that could be used to separate dissolved particles from the liquid in a solution

distillation

when a metal changes color because it has been heated a _______ change has occurred

physical

when a metal changes color because it has reacted with another substance, a _______ change occurred

chemical

the ______ theory of matter states that all particles of matter are in constant motion

Kinetic

______ between particles of a gas and the walls of the container cause pressure in a closed container of gas

collisions

a graph representing Charles's law shows that the _______ of a gas increases at the same rate as the ______ of the gas

volume/temperature

water boils when its vapor pressure becomes equal to -________ pressure

atmospheric

during vaporization, a substance changes from a ______ to a _______

liquid to a gas

neutrons and ______ have almost the same mass

protons

if element Q has 11 protons, its atomic _____ is 11

number

the ___________ of an isotope is the sum of the protons and neutrons in the nucleus

mass number

In Bohr's model of the atom, _______ move in a fixed orbit around the nucleus

electrons

when all the electrons in an atom are in orbitals with the lowest possible energy, the atom is in its ______ state

ground

Mendelev's periodic table was useful because it enabled scientists to predict properties of unknown ______

elements

the atomic mass unit(amu) is defined as one-twelfth the mass of a _____-12 atom

Carbon

from left to right across a period in the periodic table, elements become less _____ and more ________ in their properties

metallic; nonmetallic

in general, a _______ metal will be more reactive than an alkaline earth metal in the same period

alkali

the two most reactive groups of elements in the periodic table are the alkali metals and the ________

halogens

although they are called _____ lights, they can contain any noble gas

neon

in an ionic compound the attractions between cations and _____ hold the compound together

...

in its simplest form, the alloy brass consists of zinc and ______

copper

to produce stainless steel, ______ is added to iron

chromium

any part of a force that does not act in the direction of an object's motion does no _____ on an object

work

the SI unit of work is the _____

jule

you calculate work by multiplying the force acting in the direction of _______ by the distance the object moves

motion

the ideal mechanical advantage of a third-class lever is always ___ than one

less

two or more simple machines working together make up a ____ machine

compound

a watch consists of a complex system of gears. each gear acts as a continuous _____

lever

which of the following has the highest viscosity

corn syrup

a substance has a melting point of 0C and a boiling point of 100C. the substance is most likely

water

a material that is malleable and conducts electricity is most likely

a metal

which of the following is a physical change/

sawing a piece of wood in half

a substance that has high reactivity

easily combines chemically with other substances

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