What does the number 84 in the name krypton-84 represent?
the atomic number
the mass number

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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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.

Iron-55 (55Fe) is a radioactive isotope of iron with a nucleus containing 26 protons and 29 neutrons.

Answer:

54

Explanation:

yep

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

Answer:

It becomes an ion

Explanation:

The element it took from becomes a positive ion

And chlorine becomes a negative ion

Answer:

If the initial hypothesis is not supported, you can go back to the drawing board and hypothesize a new answer to the question and a new way to test it. ... Either way, the process of experimentation often leads to whole new questions to explore.

Scientific inquiry uses evidence from observations and investigations to create logical explanations to answer questions related to science. Scientific inquiry is different from the scientific method. ... Scientific inquiry helps you think outside the box to understand the natural world.

Unlike social scientists, behavioral scientists collect empirical data and use experimental methods, including testing, controls and manipulated settings.

Explanation:

Answer:

all the houses will be damaged

Explanation:

i voted for it

The oxidation number of oxygen (Group VI, period 2) is -2.

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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)

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:

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.

Answer:

4

Explanation:

atoms of O2 in the product side:

(3×2)+(2×1)=8

so to balance it:

x × 2 =8

x=4

Answer:

its letter d ..................................

Answer:

the rock layer is at least 248 million years old

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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

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:

espero que te sirva :)

Answer:

I think it's C I think that's the answer

Answer:

a table is a grid of rows and columns that intersect to form cells

Explanation:

Elements are pure substances that cannot be broken down into simpler substances by ordinary chemical means.

Answer:

a

Explanation:

the substance that exists

Answer:

320 gm

Explanation:

4 Fe + 3 O2 ----> 2 Fe2O3 How many moles of iron(III) oxide, Fe2O3 , will be produced if 4 moles of iron, Fe, are consumed

for every 4 moles of Fe, 2 moles of Fe2O3 are produced.

Fe2O3 has a molar mass of (56 X 2) + (16 X 3) = 112 + 48 =160

160 X 2 =320 gm

Answer:

423.44 moles

Explanation:

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.

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.