CHEMISTRY MIDTERM REVIEW SHEET
how many moles of platinum are equivalent to 1.20x10²⁴ atoms? (atoms to moles= atoms / 6.02 x 10²³)
1.99 x 10 moles
determine the number of moles of helium in 10.0 g of helium. the molar mass of helium is 4.00 g/mol
2.5moles
the electron configuration for nitrogen is 1s2 2s2 2p3. what does the ³ in 2p³ mean
3 valence electrons in p orbital of second level
the mass of 1 mol of gold atoms is 196.97 g. find the mass of 1 atom of gold.
3.27 x 10⁻²² ( 1/6.02x10²³=0.1661129x10⁻²³x196.97)
how many atoms are present in 8.00 mol of chlorine atoms? (moles to atoms = moles x 6.02 x 10²³)
4.816 *10²⁴ atoms
determine the mass in grams of 10.0 mol of bromine. the molar mass of bromine is 79.90 g/mol
799 grams
a team of scientists is working to discover how an enzyme affects blood cells in sheep. they are working in the field of ________ chemistry.
biochemistry
which element has the following electron configuration: [Ar] 4s² 3d¹⁰ 4p⁵?
bromine
what is an isotope?
atoms with the same number of protons but different number of neutrons
basic research is performed to increase ____________
knowledge
a scientist is working to develop better dating methods for substances that contain carbon. He is working in the field of ____________ chemistry.
organic
a scietist is working to determine the properties and changes of matter and their relation to energ of a newly discovered mineral. She is working in the field of _____________ chemistry
physical
the melting of butter is a _______ change because it does not produce any new substances.
physical
when examining a mineral, hardness and color are two of the properties used for identification. hardness and color are examples of ________ properties.
physical
distinguish between precision and accuracy
precision- exactness of a measurement accuracy- how close a measurement is to the true value
applied research is often performed to find the answer to a particular_____________
problem
distinguish between mass and weight
Mass- measure of the amount of matter Weight- measure of gravitational force on an object
write the electron configuration for nitrogen, atomic number 7
N 7 -->1s² 2s² 2p³
write the noble gas electron configuration for silicon
[Ne] 3s² 3p²
Iron and sulfur, when heated, form an iron sulfide that has different properties from either iron or sulfur. The formation of iron sulfide is an example of a ________ change.
chemical
an apple turning brown after being cut is an example of a ______ change.
chemical
Describe the law of definite proportions
chemical compound always contains the same elements in exactly the same proportions, regardless the size or source of sample.
the study of matter and changes that occur in matter best describes the science of
chemistry
some iron and sulfur are mixed together, then heated. when the result is cooled, the iron can no longer be separated from the sulfur with a magnet. the result of heating the mixture was the formation of a _______
compound
the two types of matter that are pure substances are _______ and ________
compounds and elements
matter that has neither a definite volume nor a definite shape is in the _______ state
gaseous
Gravel is an example of a ______ mixture
heterogeneous
explain the difference between a pure substance and a homogeneous mixture. give examples in your answer.
homogeneous mix can be separated by physical means a pure substance can not. you can remove salt from salt water by boiling it.
An alloy such as a gold ring is an example of a(n) ____________________ mixture.
homogenous
a chemistry student is studying the formation of quartz crystals. she is studying ____________ chemistry.
inorganic
A sample of matter can be poured from container to container. It takes the shape of its container but only takes up a certain volume. Based on this information, the sample is in the ____________________ state.
liquid
the particles of a substance in teh _________ are able to slide past each other.
liquid state
what is the relationship between isotopes, mass number, and neutrons?
mass # of is basically given by finding average of the most abundant isotope, also within mass # if # is altered by another isotope of element
Identify as metal, nonmetal, or metalloid and give two physical properties for the element Sr.
metal, malleable, good, conductor
Identify as metal, nonmetal, or metalloid and give two physical properties for the element I.
nonmetal, brittle, poor conductor of heat and electricity
what is the atomic number of an atom?
number of protons an atom has in its nucleus
in a bonfire, oxygen allows wood to combust, leaving behind ashes. in this process,oxygen and wood are the reactants, and ashes are the __________
products
explain the differences between qualitative and quantitative observations.
qualitative- descriptive (5 senses) quantitative- numerical info
technological development is performed to better our__________
quality of life
the oxygen in air causes iron to rust. iron and oxygen are ______ in this process, and rust is the product.
reactants
any substance with a definite composition is a _________
solid
a scientist is using mathematical models to isolate a new chemical process. he is working in the field of ______________ chemistry.
theoretical
two scientists are trying to determine the exact nature of the chemicals in a lava flow. they are working the field of ___________ chemistry.
thermo
what is the mass number of an atom?
total # of neutrons and protons in the nucleus
What is the law of multiple proportions?
when two elements combine with each other to form more than one compound, the mass of one element that combine with a fixed mass of the other are in a ratio of small whole numbers.
