The average atomic mass of copper can be calculated from the mass and percentage abundance of its isotopes. The average atomic mass of copper is 36.54 amu.
What are isotopes?Isotopes are atoms of same element with different mass number. Isotopes slightly differ in physical and chemical properties from each other.
The average atomic mass of an element is calculated with the formula given below:
average atomic mass = ∑ (% abundance /100) × isotopic mass.
mass of Cu-63 = 62.93 amu
% abundance = 69.15 %
mass of Cu-65 = 64.93 amu
% abundance = 30.85 %
Average atomic mass = (69.15 % /100 × 62.93 ) + (30.85 % /100 × 64.93)
= 63.54 amu.
Therefore, the average atomic mass of copper is 63.54 amu.
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4.Which scientist described the electrons as traveling in certain orbits or energy levels?
a.Dalton
b.Rutherford
c.Thomson
d.Bohr
5.In a famous experiment, scientists bombarded a very thin gold (Au) foil with positively charged alpha particles. They found that most of the alpha particles passed right through the Au foil. However, a few of the alpha particles were deflected or bounced back toward the source. How did these scientists explain their results?
a.Negative charges are spread throughout the atom.
b.Negative charges are located in the tiny nucleus of the atom.
c.Positive charges are located in the tiny nucleus of the atom.
d.Positive charges are spread throughout the atom.
6.The atomic mass represents the weighted average of an element’s
a.Ions
b.mass numbers
c.atomic numbers
d.isotopes
7.The number of protons is represented by the element’s
a.atomic number
b.mass number
c.atomic mass
d.isotope
8.The number of protons plus neutrons is represented by the
a.atomic number
b.mass number
c.atomic mass
d.isotope
9.How many valence electrons would an atom of Chlorine have?
a.2
b.3
c.7
d.8
10.An element is found to have 2 electrons in the 3rd energy level. What is this element?
a.Boron
b.Magnesium
c.Fluorine
d.Argon
11.Which shows the order of decreasing atomic size?
a.Si, Al, Mg, Na
b.I, Br, Cl, F
c.Be, Mg, Ca, Sr
d.C, P, Se, I
12.Which of the following elements has the highest ionization energy and why?
a.Argon because it has more protons in the nucleus.
b.Argon because it has a full valence shell.
c.Chlorine because it only needs one valence electron to fill its valence shell.
d.Chlorine because it attracts electrons better.
13.Which shows the order of increasing ionization energy?
a.Si, Al, Mg, Na
b.Ga, Ge, As, Se
c.Be, Mg, Ca, Sr
d.F, Cl, Br, I
14.Identify the reason why atoms decrease in size(atomic radius)across a period on the Periodic Table.
a.Gravity pulls the electrons in towards the nucleus.
b.Increase in energy levels increases the attraction and thus pulls electron cloud in.
c.Increasing strong positive nuclear charge from the nucleus pulls in the negative electron clouds and increases with the increase in protons and electrons.
d.Electrons lose energy and collapse with an increasing number of electrons and protons.
15.What is the shielding effect?
a.The neutrons shield protons from the attraction of the electrons from the first energy level.
b.Valence electrons are shared equally between atoms.
c.The repulsion of electrons in the same energy level.
d.The inner-core electrons shield outer-core electrons from the attraction to the atom’s nucleus.
16.Which statement is an accurate description of elements from Period 3 on the periodic table?
a.It contains elements with the same number of 3 protons.
b.It contains elements with the same number of3valence electrons.
c.It contains elements with the outermost protons in the same 3rd energy level.
d.It contains elements with the outermost electrons in the same 3rd energy level.
17.The column that an element is located in tells us
a.the total number of valence electrons an atom has.
b.the total number of energy levels an atom of that element has.
c.the highest energy level an atom of that element has.
d.both b & c.
18.The Halogen family of elements all have 7 valence electrons. Which column would they be in?
a.01 (IA)
b.02 (IIA)
c.4 (IVA) or 14
d.7 (VIIA) or 17
19.The Alkali and Alkaline Earth metals belong to which columns, respectively?
a.Column IA & IIA
b.Column VIIA & Column VIIIA
c.Column IIIA & IVA
20.What do carbon and silicon have in common?
a.They belong to the same column (family), therefore they have the same number of valence electrons.
b.They belong to the same column (family), therefore they have the same number of total electrons.
c.They belong to the same column (family), therefore they have the same number of energy levels.
d.They belong to the same column (family), therefore they have the same number of protons.
21.Electromagnetic radiation can take the form of which of the following types of waves
a.Heat
b.Light
c.Ultraviolet
d.All of the above
24.In order to go to a lower energy orbit, an electron
a.Must disappear
b.Must combine with other electrons
c.Lose energy of a specific amount
d.Must be transferred to another atom
25.Please choose the correct sequence that describes the excitement of an atom.
1. Such an electron transition raises the atom from the ground state to the excited state.
2. When energy is added to an atom from an outside source, its electrons move to a higher energy level (orbit)
3. As a result, the atom emits a photon.
4. When the atom is in an excited state, the electron can drop from the higher energy level to a lower energy level.
a.1, 2, 3, 4
b.4, 3, 2, 1
c.2, 1, 4, 3
d.3, 4, 1, 2
What is the volume at STP of 3.44 x 1023 molecules of CO2
gas?
a 25.1L
b 39.2 L
С
12.8 L
d 15.7 L
Answer:
C. 12.8 liters.
Explanation:
The Standard Temperature and Pressure (STP) of a gas are 273.15 K and 100 kilopascals. From Avogadro's Law, a mole of carbon dioxide contains [tex]6.022 \times 10^{23}[/tex] molecules. If we suppose that carbon dioxide behaves ideally, then the equation of state for ideal gas is:
[tex]P\cdot V = n\cdot R_{u}\cdot T[/tex] (1)
[tex]P\cdot V = \frac{r\cdot R_{u}\cdot T}{N_{A}}[/tex] (1b)
Where:
[tex]P[/tex] - Pressure, measured in pascals.
[tex]V[/tex] - Volume, measured in liters.
[tex]r[/tex] - Amount of molecules, no unit.
[tex]N_{A}[/tex] - Avogadro's number, no unit.
[tex]R_{u}[/tex] - Ideal gas constant, measured in pascal-liters per mole-Kelvin.
[tex]T[/tex] - Temperature, measured in Kelvin.
If we know that [tex]P = 100000\,Pa[/tex], [tex]r = 3.44\times 10^{23}[/tex], [tex]N_{A} = 6.022\times 10^{23}[/tex], [tex]T = 273.15\,K[/tex] and [tex]R_{u} = 8.314\times 10^{3}\,\frac{L\cdot Pa}{mol\cdot K}[/tex], then the volume of carbon dioxide at STP is:
[tex]V = \frac{r\cdot R_{u}\cdot T}{N_{A}\cdot P}[/tex]
[tex]V = \frac{(3.44\times 10^{23})\cdot \left(8.314\times 10^{3}\,\frac{L\cdot Pa}{mol\cdot K} \right)\cdot (273.15\,K)}{(6.022\times 10^{23})\cdot (100000\,Pa)}[/tex]
[tex]V = 12.972\,L[/tex]
Therefore, the correct answer is C.
Which layer of the ocean is the least dense?
Question 4 options:
they are all the same
middle layer
closest to the ocean floor
closest to the surface
Answer:
the deep ocean
Explanation:
goog le
The layer which is closest to the surface is least dense.
What are the layers of ocean?The ocean can be divided into three main layers:
The surface layer (also known as the epipelagic zone), which extends from the surface to about 200 meters deep and is the warmest and lightest layer.
The mesopelagic zone (or twilight zone), which extends from 200 to 1000 meters deep and is characterized by limited light and declining temperatures.
The bathypelagic zone (or midnight zone), which extends from 1000 to 4000 meters deep and is the coldest, darkest, and most pressure-filled layer.
Below the bathypelagic zone lies the abyssopelagic zone, which extends from 4000 to the ocean floor and is characterized by near-constant darkness and extremely cold temperatures.
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mass-mass problem:
If 25.0 grams of carbon dioxide are used in photosynthesis how many grams of glucose (C6H12O6) could be Produced according
to the following equation : 6CO2 + 6H2O → C6H12O6 + 602
Answer:
17.05 g of glucose
Explanation:
The equation of the reaction is given as;
6CO2 + 6H2O → C6H12O6 + 602
From the equation;
6 mol of CO2 produces 1 mol of C6H12O6
Converting to masses;
CO2:
Mass =Number of moles * Molar mass
Mass = 6 mol * 44 g/mol = 264 g
C6H12O6:
Mass = Number of moles * Molar mass
Mass = 1 mol * 180 g/mol = 180 g
This means 264g of CO2 produces 180g of C6H12O6
25g of CO2 would produce x g of C6H12O6
264 = 180
25 = x
x = 25 * 180 / 264
x = 17.05 g
How are molecules arranged in solid ,liquid and gas?
Answer:
A solid has the molecules tightly packed together and are held in a fixed pattern.
A liquid has molecules that are packed together in a random fashion and can move freely.
A gas has molecules that are widely separated and randomly move and collide.
Explanation:
Which of these levels of ecological organization includes the other three?
A. community
B.ecosystem
C.organism
D.population
how does a allergy develop?
PLEASE HELP!
Answer: im not fully sure but from what i rememeber Allergies develop when your immune system mistakenly identifies a thing such as pollen, mold or food as harmful then your body reacts to it
Explanation:
Uniformitarianism is the idea that
Answer:
Uniformitarianism is the idea that the natural processes operating today are the same as the natural processes that operated in the past
list 10 uses of metals
Answer:
1.In electronics
2 In medicine
3.In the construction
4.In jewelry
5.In machinery and automobiles
6.In agriculture
7.In the kitchen
8.Furniture
9. Security system
10 Bullion market
Solid sodium combines with solution of magnesium fluoride to form sodium fluoride solution and magnesium metal.
Solid sodium combines with solution of magnesium fluoride to form sodium fluoride solution and magnesium metal is adding hydrochloric acid into form magnesium chloride solution and hydrogen gas. A solution could be copper oxide is combined with solid carbon. This forms copper metal and carbon dioxide gas.
After the shuttle disaster, an unknown compound residue was removed from a piece of the debris. Upon analysis, it was found to contain 2.61 g of carbon, 6.09 g of nitrogen, and 1.31 g of hydrogen. What is its empirical formula?
Answer:
The final empirical formula is [tex]C_2 N_5 H[/tex]
Explanation:
Given
The amount of carbon, nitrogen and hydrogen in a given compound is as follows
C:N:H
[tex]2.61 : 6.09 : 1.31[/tex]
On simplifying the ration values we get
[tex]\frac{2.61}{1.31} : \frac{6.09}{1.31} : \frac{1.31}{1.31}[/tex]
So the final ratio is
[tex]2 : 5 : 1[/tex]
The final empirical formula is [tex]C_2 N_5 H[/tex]
How many atoms of aluminum (Al) are in 6.98 mol of aluminum?
Answer:
[tex]\boxed {\boxed {\sf 4.20 *10^{24} \ atoms \ Al }}[/tex]
Explanation:
To convert from moles to atoms, we must us Avogadro's number: 6.022*10²³. This tells us the number of particles (atoms, molecules, etc.) in 1 mole of a substance. In this case, it is atoms of aluminum.
We can use the number as a fraction.
[tex]\frac{6.022*10^{23} atoms \ Al}{1 \ mol \ Al}[/tex]
Multiply by the given number of moles: 6.98
[tex]6.98 \ mol \ Al *\frac{6.022*10^{23} atoms \ Al}{1 \ mol \ Al}[/tex]
The moles of aluminum will cancel.
[tex]6.98 *\frac{6.022*10^{23} atoms \ Al}{1 }[/tex]
The denominator of 1 can be ignored.
[tex]6.98 * {6.022*10^{23} atoms \ Al}[/tex]
Multiply.
[tex]4.203356*10^{24} \ atoms \ Al[/tex]
The original measurement of moles has 3 significant figures, so our answer must have the same.
For the number we calculated, that is the hundredth place. The 3 in the thousandth place tells us to leave the 0.
[tex]4.20 *10^{24} \ atoms \ Al[/tex]
There are about 4.20*10²⁴ atoms of aluminum in 6.98 moles.
I need help with this question ASAP
How are plant and animal cells similar? How are they different? To answer these questions, make a list of the different organelles in each cell. Explain how each organelle is vital to the life and function of a plant or animal.
Answer:
A plant cell contains a large, singular vacuole that is used for storage and maintaining the shape of the cell. In contrast, animal cells have many, smaller vacuoles. Plant cells have a cell wall, as well as a cell membrane. In plants, the cell wall surrounds the cell membrane.
what is the equation for hydrogen peroxide
Answer:
H2O2
Explanation:
2 hydrogen, 2 oxygen wikipedia it
Answer:
hey!
Your answer is that the equation for Hydrogen Peroxide is [tex]H_{2}[/tex][tex]O_{2}[/tex]
Explanation:
Its formed when [tex]H_{2}[/tex]O and [tex]O_{2}[/tex] react chemically together!
HOPE THIS HELPED!
How do parasites affect their hosts?
They help their hosts by consuming or using their cells.
They help their hosts by growing in size.
O They harm their hosts by growing in size.
They harm their hosts by using their hosts as a food source.
magnesium__ + sulfuric acid goes to form magnesium sulfate+ water + carbon dioxide
Answer:
carbonate
Explanation:
this is because when carbonates react with acid they form carbon dioxide and water and respective metal oxide
Every ________ will have its own unique set of quantum numbers.
Select the correct answer below:
A. atom
B. shell of electrons
C.proton
D. individual electron
Answer:
D. individual electron
Explanation:
Every individual electron will have its own unique set of quantum numbers.
What are quantum numbers?
Quantum numbers are the numbers which describe the values of conserved quantities with respect to the dynamics of a quantum system.They correspond to the Eigen values of operators which commute with the Hamiltonian quantities.
The Hamiltonian quantities can be known with precision simultaneously with the system's energy.Quantum numbers can take values of discrete sets of integers or even half-integers even though they can approach infinity in some cases.
They can specifically describe energy levels of electrons, and can also explain angular momentum,spin,etc.These are used to describe the path of an electron in an atom ,when the quantum numbers of all atoms are combined they must comply with the Schrodinger equation.
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Which of the following is true? Electrons are shared in ionic bonding
Answer:
The two most basic types of bonds are characterized as either ionic or covalent. In ionic bonding, atoms transfer electrons to each other. ... In contrast, atoms with the same electronegativity share electrons in covalent bonds, because neither atom preferentially attracts or repels the shared electrons.
Explanation:
How does a sugar solution become rock candy?
Answer:
Explanation:
A supersaturated solution is unstable—it contains more solute (in this case, sugar) than can stay in solution—so as the temperature decreases, the sugar comes out of the solution, forming crystals. The lower the temperature, the more molecules join the sugar crystals, and that is how rock candy is created.
Convert 6.03 m to km using Dimensional Analysis
Explanation:
[tex]6.03 \: m \times \frac{1 \: km}{1000 \: m} = 0.00603 \: km[/tex]
Im gonna ride it do it just how you like it and after that let's do it?
what is the answer of this.
Answer:
the hell?
Explanation:
Please help: A complete moon cycle is how many weeks
Answer:
29.5 days
Explanation:
its 29.5 days i hope it helps
Answer:
The Moon takes 27.3 days to orbit Earth, but the lunar phase cycle (from new Moon to new Moon) is 29.5 day
5.
Given: C2H5C1
P1: 951.72 kPa
P2: 362.29 kPa
T1: 653.34 K
Wanted: kelvins?
Answer: The final temperature is 248.7 K
Explanation:
To calculate the final temperature of the system, we use the equation given by Gay lussac Law. This law states that pressure of the gas is directly proportional to the temperature of the gas at constant volume.
Mathematically,
[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]
where,
[tex]P_1\text{ and }T_1[/tex] are the initial pressure and temperature of the gas.
[tex]P_2\text{ and }T_2[/tex] are the final pressure and temperature of the gas.
We are given:
[tex]P_1=951.72kPa\\T_1=653.34K\\P_2=362.29kPa\\T_2=?[/tex]
Putting values in above equation, we get:
[tex]\frac{951.72}{653.34}=\frac{362.29}{T_2}\\\\T_2=248.7K[/tex]
Thus the final temperature is 248.7 K
HELP ME PLEASE!!!
One liter of water is cooled from 20°C to 3°C inside a refrigerator. What is the change in temperature in °F? K?
Answer:
Decrease of temperature by 62.6°F and 290.15°
Explanation:
First identify change in C: 17 degrees
now convert to Fahrenheit and Kelvin
Fahrenheit: 17 * (9/5) +32 = 62.6°
Kelvin: 17 + 273.15 = 290.15°
BRAINLIEST AND POINTS!!
Describe three ways in which scientists communicate the results of their work.
Answer:
There are several ways that scientists communicate our results, including written reports and scientific journal publications, and by giving presentations to our colleagues and the public. One popular venue for scientists to present to colleagues is at scientific conferences.
Explanation:
Answer:
-Good writing explaining their data they have discovered
-Their research is shared with the other scientists, and is peer reviewed
-They present their results at national and international conferences where other scientists can listen and give their input.
Explanatio
____Na3PO4+____CaCI2 --->____NaCI+ ____Ca(PO4)2
Answer:
3CaCi2 + 2Na3PO4 → Ca3(PO4)2 + 6NaCi
Explanation:
Dona is attempting to make an electromagnetic to pick up old nails in her driveway. Which of these materials would be best to us for the core to make the strongest electromagnetic to pick up the most nails?
Answer:
The materials would be best to us for the core to make the strongest electromagnetic to pick up the most nails is described below in detail.
Explanation:
Use a couple of wire strip-pers to exclude some centimeters of insulation from every end of the cable. Skillfully cover the cable around the nail. The more cable you enclose around the nail, the more effective your electromagnet will be. Compose certain that you leave sufficient of the cable unwrapped so that you can connect the battery.
The diagram shows movement of thermal energy
In which areas of the diagram does conduction occur?
W and X
X and Z
Y and Z
Z and W
Answer:
Y AND Z
HOPE IT HELPS THANK ME LATER.
Answer:
B. Y and Z
Explanation:
I need help with this question ASAP
Answer:
True
Explanation:
Asexual reproduction does not involve sex cells or fertilization . Only one parent is required, unlike sexual reproduction which needs two parents. As a result, the offspring are genetically identical to the parent and to each other.