Answer:
when the chemical composition of a substance change and it is not reversible it is called phase change.for example: turning milk in to yogurt
Based on the periodic table, what is the oxidation number of oxygen (Group VI, period 2) in compounds? a) 0 b) +2 C) -2 d) 1
The oxidation number of oxygen (Group VI, period 2) is -2.
The electrical charge of an atom describes its Oxidation number.\The number of electrons that must be gained or lost in an atom's valence electron shell to make it to be filled or half-filled gives us the oxidation number value.When the atom gains electrons,it acquires a negative oxidation number. When the atom loses electrons,it acquires a positive oxidation number
Oxygen has 8 electrons with {He] 2s² 2p⁴ configuration. With 6 electrons in its valence shell, it need to gain 2 electrons to achieve stability, When it gains 2 electrons, it acquires a negative oxidation number of -2.
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Nitrogen has two naturally occurring isotopes.
Predict the number of neutrons in the two isotopes of
nitrogen, N.
How many protons?
Electrons?
Answer:
Nitrogen has 7 protons and 7 electrons and 7 neutrons.
Explanation:
The atomic number of an element is the number of electrons and protons they have. The atomic mass - the atomic number of an element equals the number of nuetrons. The atomic mass of nitrogen is 14 and the atomic number is 7 therefore we have to subract, 14-7=7.
C3H4(g) + xO2(g) → 3C02(g) + 2H2O(g)
-
What is the value of the coefficient x in this
equation?
Answer:
4
Explanation:
atoms of O2 in the product side:
(3×2)+(2×1)=8
so to balance it:
x × 2 =8
x=4
Carbon dioxide, when present in sufficient amounts, will bind with water to form ____________ , which is capable of dissociating into bicarbonate and hydrogen ions.
Answer:
Carbon dioxide, when present in sufficient amounts, will bind with water to form carbonic acid, which is capable of dissociating into bicarbonate and hydrogen ions.
Explanation:
With the help of carbonic anhydrase which further catalyzes the reaction to convert carbonic acid back into carbon dioxide and water. The carbon dioxide is then expelled from the lungs.
Based on the balanced chemical equation shown below, determine the mass percent of Fe3+ in a 0.6450 g sample of iron ore, if 22.40 mL of a 0.1000 M stannous
chloride, SnCl2(aq), solution is required to completely react with the Fe3+ present in the ore sample. The chemical equation for the reaction is
2 Fe3+ (aq) + Sn2+ (aq) →2Fe2+ (aq) + Snº+(aq).
O 19.40%
O 6.196%
O 38.79%
O 9.697%
Answer:
38.9%
Explanation:
below, determine the mass percent of Fe3+ in a 0.6450 g sample of iron ore, if 22.40 mL of a 0.1000 M stannous chloride, SnCl2(aq), solution is required to completely react with the Fe3+ present in the ore sample. The chemical equation for the reaction is
2 Fe3+ (aq) + Sn2+ (aq) →2Fe2+ (aq) + Snº+(aq).
O 19.40%
O 6.196%
O 38.79%
O 9.697%
2 Fe3+ (aq) + Sn2+ (aq) →2Fe2+ (aq) + Snº+(aq).ole of Sn2+
for every mole of Sn2+, tere are 2 moles of Fe3+
22.4/1000L of 0.1000 M Sn2+ = 22.4 X 0.10/1000 = 0.00224 moleso there are 0.00224 X 2= 0.00448 moles Fe3+
iron atomic mass is 56
56 X 0.00448 = 0.251 gm Fe3+
so the mass % of the Fe3+ in the 0.645 gm iron ore sample is
(0.251/0.645) X 100 = 38.9%
Zn(s) + Cu2+ —> Zn2+(aq) + Cu(s)
In this reaction, copper __ electrons, therefore it is the __ agent.
A. loses, reducing
B. gains, oxidizing
C. loses, oxidizing
D. gains, reducing
Answer: do you guys know the answer
Explanation:
Answer:
gains,oxidizing
Explanation:
Zn(s) + Cu^2+---> Zn^2+(aq) + Cu(s)
I got the answer right on usatp.
Describe how to do an experiment to show that when you dissolve salt in water the salt is still there.
Answer:
When salt is dissolved in water, the particles of salt get into the spaces between particles of water and starts dissolving and disappear.
Explanation:
how many electrons does Fe-55 have
Iron-55 (55Fe) is a radioactive isotope of iron with a nucleus containing 26 protons and 29 neutrons.
Answer:
54
Explanation:
yep
Which of the following elements has the lowest first ionizition energy ?
1 ) Li
2)Mg
3) Na
4) Al
Answer:
I think Mg is correct I am not sure
please help me
Type the correct answer in the box. Spell all words correctly.
What does Dalton's atomic theory propose?
A ______ causes rearrangement of atoms.
how does the molecular geometry change if you replace a bond with a lone pair?
Answer:
The overall molecular shape (the molecule geometry) changes because of the lone pairs repulsion, but the electron geometry does not change because whether an atom or a lone pair is added there's still two electrons being added.
Explanation:
hope that helps :D
Answer:
Un par solitario o par de electrones no compartidos es un par de electrones de valencia que no se encuentra formando un enlace, ni compartido con otros átomos. Cuando un átomo se agrupa con otros para formar una molécula, sus electrones más externos -también conocidos como electrones de capa de valencia- dejan de pertenecer únicamente al átomo del que provienen, pasando a pertenecer a la molécula formada. Los orbitales atómicos de valencia dejan de existir como tales y pasan a formar orbitales moleculares con características diferentes a las originales. Como los pares solitarios se encuentran en la capa más externa de los átomos, cuando estos átomos forman moléculas pasan a formar parte del conjunto de electrones de valencia de la molécula. De esto se deduce que los pares solitarios son, de hecho, un subconjunto de los electrones de valencia de la molécula a la que pertenecen.
Explanation:
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What mass of KBr (in grams) do you need to make 250. 0 mL of a 1. 50 MKBr solution?.
Answer:
KBr final solution:
V = 250mL --> 0.25L
Concentration/Molarity = 1.5 mol/L
To find the amount of moles of KBr here, just multiply the volume by the concentration (0.25 x 1.5 = 0.375 mol)
So the amount of moles for KBr is 0.375 mol. Now we know that the mass divided by the molar mass (the atomic mass values of K and Br in the periodic table added together) would give us the amount of moles aswell.
n = moles
m = mass
M = molar mass
n = m/M
so if we rearrange this equation to find mass, we would get:
m = n x M
Molar mass for KBr: (39.09) of K + (79.90) of Br = 118.99
m = 0.375 mol x 118.99
m = 44.62g
Therefore 44.62g of KBr is needed to make 250mL of a 1.5 M KBr solution.
:) help please I sent in a photo
Answer:
I think it's C I think that's the answer
How many protons,neutrons and electrons make a hydrogen atom
Explanation:
A hydrogen atom has an atomic number of 1.
So it's proton number will always be 1.
A neutral hydrogen atom does not have any charge.
So it has the same amount of electrons as protons, which turns out to be also 1.
A neutral hydrogen atom has an atomic mass of ≈1.00794amu≈1amu.
To find the amount of neutrons, we take the proton number and subtract it from the mass number.
1−1=0
So a neutral hydrogen atom has no neutrons.
In summary,
A hydrogen atom has
1 proton
1 electron
0 neutrons
another way of explaining:
The number of protons is the atomic number, and the number of protons plus neutrons is the atomic mass. For hydrogen, the atomic mass is 1 because there is one proton and no neutrons. For helium, it is 4: two protons and two neutrons
when chlorine gains an electron to have 8 valence electrons and become stable, will it increase, decrease or stay the same in terms of the atomic radius
Answer:
It becomes an ion
Explanation:
The element it took from becomes a positive ion
And chlorine becomes a negative ion
Look at the three kinds of houses shown in the simulation. Which house do you think will best resist damage from a tsunami? Which house will suffer the most damage from a tsunami? Do you think any of the houses will survive a large tsunami? Write down your predictions. https://app.edmentum.com/redirect//358692this link will help the people answer my question the link
Answer:
all the houses will be damaged
Explanation:
i voted for it
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B. A +ion (positive ion, one with extra positive charge)?
Two containers of gas have the same volume, temperature and pressure. One container has a sample of oxygen gas having a mass of 3.95g. The other container has a gas with a mass of 2.99g. Determine the molar mass of the gas in the second container.
Answer:
24.3
Explanation:
Two containers of gas have the same volume, temperature and pressure. One container has a sample of oxygen gas having a mass of 3.95g. The other container has a gas with a mass of 2.99g. Determine the molar mass of the gas in the second container.
O2 has a molar mass of 16 X 2 =32
the number of moles for O2 is the weight divided by the molar mass or, but since the two container have the same P,V, AND T they have the same number of moles since
PV =nRT
SO
the weight of the gas in the second container divided by its molar mass =
0.123
or
2.99/? = 0.123
so
? = 2.99/o.123 = 24.3
Count the following atoms
NEED ANSWER ASAP
How many molecules of H2O are there in 200,000,000L of gas at STP?
Which phrase best describes the vapor point of a substance?
the strength of the bonds between molecules of a substance that is in a gaseous state
the amount of heat energy required to change a substance from a liquid to a gas
the temperature at which additional heat energy causes the substance to change from a liquid to a gas
the average kinetic energy of the molecules of a substance in its gaseous state
The phrase which best describes the vapor point of a substance is Choice C; the temperature at which additional heat energy causes the substance to change from a liquid to a gas.
The vapour point of a substance by definition is the state of a substance at which upon addition of any amount of heat energy; he substance undergoes a phase change from liquid to solid.
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5. How could you use Kepler's 3rd Law to find the relationship between all of the
moons of Jupiter?
Answer:
essentially through the use of keplers 3rd law comparing the proportionality of a planets squared versus cubed orbital patterns you can determine how fast a planet will orbit something and complete a full orbit
Explanation:
Kepler's Third Law: the squares of the orbital periods of the planets are directly proportional to the cubes of the semi-major axes of their orbits. Kepler's Third Law implies that the period for a planet to orbit the Sun increases rapidly with the radius of its orbit. (from NASA)
A. Parts of Solutions
1. The substance that exists in the greatest quantity in a solution is called
the
Answer:
a
Explanation:
the substance that exists
how long does it take to cook a 12 pound turkey in the oven
How are the forces acting on an airplanes flying similar to the forces acting on a boat moving through water?
Answer: The four forces acting on an aircraft in straight-and-level, unaccelerated flight are thrust, drag, lift, and weight.
Explanation:
When gravity is the only force acting on an object, the object is said to be in__.
Which of the following terms is a chemical substance made of a single type of atom that cannot be broken down into a simpler substance?
A- nucleus
B- molecule
C- Compound
D- Element
Assume trilobites went extinct 248 million years ago.
If a trilobite is found in a rock layer, what do you
know about the age of that rock layer?
Answer:
the rock layer is at least 248 million years old
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How do you know how to order an empirical formula?
Answer:
Start with the number of grams of each element, given in the problem. the mass of each element = the percent given. Convert the mass of each element to moles using the molar mass from the periodic table. Divide each mole value by the smallest number of moles calculated.
can someone send the working and answer for this question with formulas used and all
Answer:
its letter d ..................................