What is true for ALL of the examples of electromagnetic waves?

Answer:

%abundance of isotope B-11 is 80%, therefore, the %abundance of isotope B-10 is 20%.

Explanation:

The average atomic mass of an element is actually a weighted average atomic mass, taking into account the percent abundance of the naturally occurring isotopes of the element.

To calculate the weighted average mass, you must take the sum of atomic masses of all the naturally occurring isotopes multiplied by their %abundance.

Ave At. Mass = sum of [(isotopic mass)(%abundance)]/100

If we let the %abundance of B-11 be represented by X, then the %abundance of B-10 must be (100-X).

Now we can set up the following equation and solve for X

10.8 = [(10)(100-X) + (11)(X)]/100

1080 = 1000 - 10X + 11X

80 = X

So, the %abundance of isotope B-11 is 80%, therefore, the %abundance of isotope B-10 is 20%.

If 3-kg of copper (I) sulfide reacts with excess oxygen, 3.9 kg of copper metal may be produced.

Let's consider the following balanced equation for the obtaining of pure copper.

Cu₂S(s) + O₂(g) ⇒ 2 Cu(s) + SO₂(g)

The molar mass of Cu₂S is 95.61 g/mol. The moles corresponding to 3 kg (3000 g) of Cu₂S are:

[tex]3000 g \times \frac{1mol}{95.61g} = 31 mol[/tex]

The molar ratio of Cu₂S to Cu is 1:2. The moles of Cu obtained from 31 moles of Cu₂S are:

[tex]31 mol Cu_2S \times \frac{2molCu}{1molCu_2S} =62 mol Cu[/tex]

The molar mass of Cu is 63.55 g/mol. The mass corresponding to 62 moles of Cu is:

[tex]62 mol \times \frac{63.55g}{mol} = 3.9 \times 10^{3} g = 3.9 kg[/tex]

If 3-kg of copper (I) sulfide reacts with excess oxygen, 3.9 kg of copper metal may be produced.

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Explanation:

Sue added salt to water in order to make a salt solution

the original amount of water is 400 grams

In order for Sue to obtain 405 grams of salt solution using 400 grams of water, 5 grams of salt must be added.

Answer: (D) 5 grams

Explanation: the reason I would chose this is because if you do the simple math of 405-400 you get 5 so if he has 400 in the beginning he would have to add something to make it 405 grams and that something would have to be 5 grams of salt. hoped this helped no need for brainiest just happy to help.:)

and please tell me if I am wrong.

The pH of the solution is approximately : 1.05

Given data :

volume of HCl = 68.00 mL = 0.068 L

concentration of HCl = 0.280 M

Volume of NaOH = 60 mL = 0.6 L

concentration of NaOH = 0.125 M

First step : determine the number of mol of HCl and NaOH

mol of HCl = 0.068 * 0.280  = 0.0190 mol HCl

mol of NaOH = 0.06 * 0.125 = 0.0075 mol NaOH volume of

excess moles of H⁺ after reaction  = 0.0190 - 0.0075 = 0.0115 mol

Next step : determine the pH value of the solution

Total volume of solution = 0.068 + 0.060 = 0.128

concentration of the solution [ H⁺ ] = excess moles / total volume

                                                         = 0.0115 / 0.128 = 0.0898

Therefore

pH = - log [ H⁺ ]

    = - log ( 0.0898 ) = 1.047 ≈ 1.05

Hence we can conclude that The pH of the solution is approximately : 1.05 .

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Answer:

32 electron

Thus,the fourth level can hold up to 32 electrons,2 in the s orbital,6 in the three p orbitals,10 in the five d orbitals,and 14 in the seven f orbitals.

Answer:

The small intestine

Explanation:

You are the small intestine

Answer:

H2O forms a bent structure due to the presence of 2 lone pairs over O Atom. This makes the bond angle 104.5° NH3 forms a pyramidal structure due to presence of 1 lone pair. This makes the bond angle 107°

Answer:

Check the attached one..I only draw the Dot method of Magnesium and Fluorine.. since i love chemistry ..Hope this helps you...Balance you have to do it yourself..If you didn't get the answer let me know in the comments..But you have try okay..

Answer:

1

Explanation:

Mass of

C

a

C

N

2

= 75.0 g

From the equation,

C

a

C

N

2

(

s

)

+

3

H

2

O

(

l

)

→

C

a

C

O

3

(

s

)

+

2

N

H

3

(

g

)

1 mol of

C

a

C

N

2

reacts with 3 moles of water to give calcium carbonate and ammonia.

Number of moles of

C

a

C

N

2

,

n

=

G

i

v

e

n

m

a

s

s

M

o

l

a

r

m

a

s

s

Molar mass of

C

a

C

N

2

= 92.11 g/mol

Therefore,

n

C

a

C

N

2

=

75

g

92

.11

g

/

m

o

l

=

0

.814

m

o

l

Moles of water =Therefore,

n

C

a

C

N

2

=

75

g

92

.11

g

/

m

o

l

=

0

.814

m

o

l

Moles of water =

3

×

0

.814

m

o

l

e

s

=

2

.442

m

o

l

e

s

Mass of water needed;

=

m

o

l

e

s

o

f

w

a

t

e

r

×

m

o

l

a

r

m

a

s

s

o

f

w

a

t

e

r

=

2

.442

m

o

l

×

18

g

/

m

o

l

=

43

.956

g

Thus, 43.96 g of water is needed to react with 75 g of

C

a

C

N

2

.

Answer:

Na₂SO₄·10H₂O.

Explanation:

Hello.

In this case, since the anhydrous sodium sulfate is:

[tex]Na_2SO_4[/tex]

Whose molar mass is:

[tex]M=23+32+16*4=142 g/mol[/tex]

But the total hydrate's molar mass is 322.1 g/mol, we can compute the mass of water:

[tex]m_{water}=322.1-142=180.1g/mol[/tex]

Thus, the molecules of water are found by diving the total mass of water by the mass of one mole of water:

[tex]#water=\frac{180.1}{18}=10[/tex]

It means, that the formula is Na₂SO₄·10H₂O.

Best regards.

Taking into account the reaction stoichiometry, you can observe that:

In first place, the balanced reaction is:

Ca₃P₂ + 6 H₂O  → 3 Ca(OH)₂ + 2 PH₃

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

Then, by reaction stoichiometry, you can observe that:

Learn more about the reaction stoichiometry:

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Answer:

D. Electrical charge

Explanation:

What actually caused the tissue paper to move towards the balloon is "electrical charge".

When they rubbed the balloon with a piece of wool, the wool looses electrons which gives it a positive charge while the balloon gains electrons which gives it a negative charge.

The pieces of tissue paper is able to move toward (i.e attracted) the balloon because the negatively charged balloon is attracted to the positively charged tissue paper which was neutral.

Answer:

D

Explanation:

Answer:

fasting blood work

Explanation:

edge 2022

Answer:

Increased

Explanation:

Answer:

When there are too many protons, some of the outer protons are loosely bound and more free to react with the electron. But most atoms do not have too many protons, so there is nothing for the electron to interact with. As a result, each electron in a stable atom remains in its spread-out wavefunction shape.

In an atom, there is a nucleus made up of neutral charged, neutrons, and positively charged protons. The reason why electrons which are negatively charged, don't fly off is due to its stronger attraction to the protons. ... This, however, still allows the electrons to move around the nucleus of an atom.

Answer:   This is an acid-base reaction (neutralization): Al(OH) 3 is a base, HBr is an acid. ; Colorless gas with a sharp, irritating odor.

...

Search by products (AlBr 3, H 2O)

1 HBr + Al(OH)3 → H2O + AlBr3

2 Al2O3 + HBr → H2O + AlBr3

Explanation:

Explanation:

p=mv

=(4.237)(2.5x10^-2)^3

=6.6x10^-5 kgm-3

Using the stoichiometry of the reaction, we can obtain the molar mass of the complex as 276 g/mol. The number of moles iron II as 0.00181 moles and the mass of iron II as  0.1 g.

A redox reaction is one in which there is loss or gain of electrons. The equation of the reaction is 5Fe2+ + MnO4- + 8H+ - - > 5Fe2+ + Mn2+ +4H2O

Number of moles of permanganate =   0.0200 mol. dm3 * 18.10cm3/1000 L

= 0.000362 moles

If 5 moles of iron II reacted with 1 mole of permanganate

x moles of iron II reacts with 0.000362 moles of permanganate

x = 5 moles * 0.000362 moles/ 1 mole

= 0.00181 moles of iron II

Recall that;

Number of moles = mass/molar mass

Molar mass of iron  II = 56 g/mol

0.00181 moles  = x/56 g/mol

x = 0.00181 moles * 56 g/mol = 0.1 g

If 1 mole of the complex contains 1 mole of iron then;

0.00181 moles = 500 * 10^-3/MM

MM= 500 * 10^-3/0.00181 moles

MM = 276 g/mol

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Answer:

Burning a match... i'm pretty sure.

Explanation:

All the other are phisical changes while Fire is a chemical reaction.

Answer:

Burning a match is a chemical change.

Explanation:

Burning is defined as the rapid oxidation of a combustible material.

Complete oxidation of the match stick results in an entirely different compound (the ash) while electrons are lost by the wood of the match.

Answer:

Column on the periodic table tell the number of valence electrons and the types of chemicals, such as metals, nonmetals, alkaline earth metals, metalloids, halogens, noble gases.

Explanation:

The periodic table is an arrangement of the elements in order of their atomic numbers so that elements with similar properties appear in the same vertical column or group.

Answer: C Snow

Explanation:

Because the temperature is low and it is below freezing temperature. Sorry if I am wrong.

Answer:

the answer should be A. energy that depends on an object's motion

Answer: A

Explanation: Kinetic energy is energy of build up of motion .

Answer:Ithink erosion cuz if we can tell how long ago it eroded we can see how old it is

Explanation:

Answer:

C. Carbon Dioxide-oxygen Cycle

Explanation:

Bacteria plays an important role in carbon cycle. Bacteria are decomposers that break down organic compounds. They decomposes plant and animal waste products and return carbon back in the environment.

Hope it helps:)))

1. Summer Solstice

Summer Solstice is an astronomical event that marks the longest day of the year and the official beginning of summer in the Northern Hemisphere. It takes place when the sun reaches its highest point in the sky, directly over the Tropic of Cancer. During this time, the days have the most hours of sunlight and the nights have the least hours of darkness. This is due to the Earth's tilt in relation to the Sun. On the day of the Summer Solstice, the sun rises earliest and sets latest. This event is celebrated around the world, with many cultures creating rituals to honor the season. In the U.S., some people celebrate by gathering together for festivals, bonfires and fireworks. Others mark the day by practicing yoga, meditating or spending time outdoors in nature. Summer Solstice is a time of renewal and celebration, a reminder of the power of light, and of the beauty of the changing seasons.

2. seasons

3. Winter Solstice

4. Equinoxes

To learn more about  Summer Solstice

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#SPJ1

Answer:

Explanation:

Given data:

Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.

Formula:

Molarity = number of moles of solute / L of solution

Answer:

A

Explanation:

determine which chemicals to use to fight different types of fires

the only one that relates to chem