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3 years ago

The average atomic mass for any element will be closest to the average atomic mass of the ________ isotope.

Chemistry

1 answer:

dezoksy [38]3 years ago

5 0

Answer:

Explanation:

The average atomic mass for any element will be closest to the average atomic mass of the __different______ isotopes.

To calculate the average atomic mass of any element, the mass spectrometry method helps to determine the proportion/percentage/fraction by which each of the isotopes of an element occurs in nature. The proportion is called the geonormal abundance or abundance. From this, the average atomic mass of an element from different isotopes can be calculated.

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Highest ionization energy: Li, Be, B

Ad libitum [116K]

Hello!

On the periodic table, as we go down the periodic table, the ionization energy decreases, but as we go across the periodic table (left to right), the ionization increases.

On the periodic table, lithium (Li) is located in column one, beryllium (Be) is located in column two, and (B) boron is located in column 13. As stated above, when we go across the periodic table (left to right), the ionization increases.

Therefore, the element with the highest ionization energy is Boron, or symbol B on the period table.

3 0

3 years ago

In the reaction n2 + 3h2 ---> 2nh3, how many grams of nh3 are produced if 25.0 g n2 reacts with excess h2? question 10 option

Lisa [10]

Molar mass of N2 = 28

Moles of N2 = 25 / 28 = 0.89

So, moles of NH3 produce = 2 x 0.89 = 1.78

Note: H2 is in excess. so no need to care about it.

8 0

3 years ago

100 PIONTSSSSS HELP ASAP

valina [46]

Left Panel

Short answer A

Solution

Since you have been given choices, my sloppy numbers will do, but it anyone is going to see this, YOU SHOULD CLEAN THEM UP WITH THE NUMBERS THAT COME FROM YOUR PERIODIC TABLE.

Equation

Sodium Phosphate + Calcium Chloride ===> Sodium Chloride + Calcium Phosphate.

Na3PO4 + CaCl2 ===> NaCl + Ca3(PO4)2

Step One

Balance the Equation

2Na2PO4 + 3CaCl2 ==> 6NaCl + Ca3(PO4)2

Step Two

Find the molar mass of CaCl2

Ca = 40

2Cl = 71

Molar Mass = 40 + 71 = 111 grams/mole

Step Three

Find the number of moles of CaCl2

Given mass = 379.4

Molar Mass = 111

moles = given Mass / molar Mass

moles of CaCl2 = 379.4/111 = 3.418 moles

Step Four

Find the number of moles of Ca3(PO4)2 needed.

This requires that you use the balance numbers from the balanced equation.

For every 3 moles of CaCl2 you have, you get 1 mole of Ca3(PO4)2

n_moles of Ca3(PO4)2 = 3.418 / 3 = 1.13933 moles

Step Five

Find the molar mass of Ca3(PO4)2

From the periodic table,

3Ca = 3 * 40 = 120

2 P = 2 * 31 = 62

8 O = 8 * 16 =128

Molar Mass = 120 + 62 + 128= 310 grams per mole.

Step Six

1 mole of Ca3(PO4)2 has a molar mass of 310 gram

1.13933 moles of Ca3(PO4)2 = x

x = 1.13933 moles * 310 grams /mole

x = 353.2 grams. As you can see, even with my rounding I'm only out 0.3 of a gram. DON'T FORGET TO PUT THIS TO THE PROPER SIG DIGS IF SOMEONE ELSE IS GOING TO SEE IT.

Middle Panel

Short Answer C

Equation

2HCl + Mg ===> H2 + MgCl2

The object of the first part of the game is to find the number of moles of H2.

Step One

Find the moles of HCl

1 mole HCl = 35.5 + 1 = 36.5

n = given mass divided by molar mass

n = 49 grams / 36.5 = 1.34 moles.

The balanced equation tells you that for ever mole of H2 produced, you need 2 moles of HCl. That's what the balance numbers are for.

So the number of moles of H2 is 1.34 / 2 = 0.671 moles of H2.

Now we come to Part II. We have to use an new friend of yours that I have seen only once before from you.

Find V using PV = nRT

R is going to be in kPa so the value of R = 8.314

V = ???

n = 0.671 moles

T = 25 + 273 = 298oK

P = 101.3 kPa

101.3 * V= 0.671*8.314 * 298

V = 0.671 * 8.314 * 298 / 101.3

V = 16.4

The answer is C and again, I have rounded almost everything except R, although it can go out to 8 places.

Right Panel

I can't see the panel. I don't know what the problem is. Never mind I got it. I'm going to be a little skimpy on this one since I've done two like it and they are long.

LiOH + HBr ===> LiBr + H2O and the equation is balanced.

You have to figure out the moles of LiOH and HBr. Use the LOWEST number of moles

n_LiOH = given mass / molar mass = 117/(7 + 16 + 1) = 117 / 24 = 4.875 moles

n_HBr = given mass / molar mass = 141/(1 + 80) = 141 / 81 = 1.741 moles

HBr is the lower number. That's all the LiBr you are going to get is 1.741. There is no adjustment to be made from the balance equation.

n = given mass / molar mass multiply both sides by the molar mass

n * Molar mass (LiBr) = n * (7 + 80) = 1.741 * 87 = 151 grams of

The answer is C

6 0

2 years ago

Which models of the atom does the experimental evidence from Bohr's hydrogen experiment support? Explain why these models are co

STALIN [3.7K]

Answer:

Rutherfords

Explanation:

The model of the atom supported by Bohr's hydrogen experiment is the Rutherford's model of the atom.

Rutherford through his experiment on gold foil suggested the atomic model of the atom. The model posits that an atom has a small positively charged center(nucleus) where nearly all the mass is concentrated.

Surrounding the nucleus is the large space containing electrons.
In the Bohr's model of the atom, he suggested that the extranuclear space of the atom is made up of electrons in specific spherical orbits around the nucleus.

8 0

3 years ago

Help please I’ll give you brainless

Nikitich [7]

Answer:

By atomic number?

Explanation:

fingers crossed its right :/

8 0

2 years ago