How many moles are in 7.91 X 1022 atoms of He?

Answers

Answer 1

Answer:

amount of He = (7.91 × 10^22) ÷ (6.02 × 10^23) = 0.131mol (3sf)

Explanation:

you make use of the mole concept formula

amount(mol) = number of particles ÷ 6.02 × 10^23

(6.02 × 10^23 is the avogadro constant, which is an extremely important number in this formula for mole concept)


Related Questions

Complete the sentence. Select all that apply. A beta particle: is electromagnetic energy is emitted from the nucleus has zero charge has a +2 charge has a -1 charge is an electron

Answers

Answer: has a -1 charge

is an electron

is emitted from the nucleus

Explanation:

The beta particle is basically an electron with -1 charge and no mass.

Beta particles are  fast-moving electron emitted by radioactive decay of substances. Beta particles have a charge of - 1, and a mass of about [tex]\frac{1}{2000}[/tex] th of a proton. This means that beta particles are the same as an electron.

A beta particle, also called beta ray or beta radiation [tex](\beta)[/tex], is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay.

A beta particle is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide.

Please help!!! I'll give brainliest to the most helpful answer
please this is due today and I have no idea :// 3

Answers

87) A
88) D
89) B
90) E
91) C

Questions
1. How would you describe life and why?​

Answers

boring. To be honest we all die at the end of the day

An example of a high explosive is what?

Answers

Answer:

High explosives do not need to be contained to make their bang. Nitroglycerine, trinitrotoluene, and RDX are high explosives.

Explanation:

Write the chief ore of sodium and potassium respectively?

Answers

Answer:

K-sylvite

Na-rock salt

Explanation:

Sylvite is a colourless or white mineral consisting of potassium chloride, occurring typically as cubic crystals(Oxford dictionary). It is the primary ore of potassium metal. It appears colorless, sometimes with a shade of red.

Rock salt is a primary ore of sodium. It is found in rocks, seas etc. Rock salt is sometimes commonly called halite. It usually appears white in colour and is rich in sodium.

PLEASE HELP I'M BEING TIMED!! Which type of star system has the most stars?
A. Open Cluster
B. globular cluster
C. Eclipsing binary
D. binary star system ​

Answers

Answer:

Hi! It's B - globular cluster

Answer:

B Globular Cluster

Explanation:

Sorry if I am wrong :)

Most of the carbon in the rocks that form Earth's mantle and crust was stored there when Earth formed. The rest of Earth's carbon is stored and exchanged in many ways.In a model of the carbon cycle, which process does NOT contribute directly to the storage of carbon within sediment?

Answers

Answer:

Photosynthesis.

Explanation:

In photosynthesis process, carbondioxide gas enters into plant leaves from which plant produces organic molecules such as glucose. This glucose helps the plant to increase it growth and complete development stages and finally the plant dies and buried in the soil so due to decomposition process, the carbon present in the plant body releases in the soil and become part of sediments. So indirectly photosynthesis process provides carbon to the soil.

Shonda’s car gets an average of LaTeX: 27 miles per gallon. Gas costs $LaTeX: 2.25 per gallon and she drives LaTeX: 892 miles to get from Baltimore, MD to Orlando, FL. What are the conversion factors she could use to calculate the cost of gas to get from Baltimore to Orlando? How much will she spend on gas?

Answers

The conversion factors she could use to calculate the cost of gas : 33.037 gallon from Baltimore to Orlando

She will spend $74.33 on gas

Further explanation

Given

Shonda’s car : 27 miles per gallon

Gas cost = $ 2.25/gallon

Distance Baltimore to Orlando = 892 miles

Required

Cost of gas

Solution

Total gallon needed to get from Baltimore to Orlando :

892 miles : 27 miles/gallon = 33.037 gallon

Cost of gas :

33.037 gallon x $2.25/gallon = $74.33

What is the balanced equation for the manufacture of ethanol from glucose

Answers

Answer:

C6H12O6 → 2C2H5OH + 2CO2

Explanation:

Glucose is an organic molecule, specifically a sugar, with the formula C612O6 while ethanol is another organic molecule with formula; C2H5OH.

However, as rightly said in this question, ethanol can be got from glucose via a process called fermentation in the presence of a catalyst called YEAST. The balanced equation is as follows:

C6H12O6 → 2C2H5OH + 2CO2

What is a part's structure related to?

Answers

huh i need you to be more specific

What are two types of matter are pure substances

Answers

Answer:

Elements and compounds are two types of pure substances.

Explanation:

Balance the chemical reaction for the combustion of methanol by adding the correct coefficients below

__CH3OH +__O2(little box)__CO2 +__H2O

Answers

Answer:

[tex]2~CH_3OH+3~O_2\rightarrow2~CO_2+4~H_2O\\[/tex]

The coefficients would be 2, 3, 2, and 4.

Explanation:

If we want to check this we would multiply the coefficient by each element. What we want is to have the same number of atoms on each side.

Reactant side:

# of carbon atoms: 2# of hydrogen atoms: 8# of oxygen atoms: 8

Product side:

# of carbon atoms: 2# of hydrogen atoms: 8# of oxygen atoms: 8

And that's it!

a sample of an unknown metal has a mass of 21.6g and volume of an 8.00cm3 calculate the density of the unknown metal

Answers

Answer:

2.70 g/cm³

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\[/tex]

From the question we have

[tex]density = \frac{21.6}{8} \\ = 2.7[/tex]

We have the final answer as

2.70 g/cm³

Hope this helps you

Solve and use correct sig figs AND units: (Example of how to type: 3.26 m2)
The density of mercury is 13.6 g/mL. What is the mass of 3,426 mL of mercury?

Answers

Answer:

m = 46593.6 g

Explanation:

Given data:

Mass of mercury = ?

Volume of mercury = 3426 mL

Density of mercury = 13.6 g/mL

Solution:

Formula:

d = m/v

d = density

m = mass

v = volume

by putting values,

13.6 g/mL = m/ 3426 mL

m =  13.6 g/mL × 3426 mL

m = 46593.6 g

when 45mL of 0.25mol/L sulfuric acid is mixed w/ 25mL of 0.58mol/L Calcium hydroxide, the solution has a?

Answers

Pls pls help I don’t have time HELP ASAP. It also detects if it’s right or wrong. Pls pls help I don’t have time HELP ASAP. It also detects if it’s right or wrong.

2C3H7OH + 9O2 --> 6CO2 + 8H2O

Determine the number of grams of CO2 produced from the reaction of 5.55 moles of C3H7OH?

a
1466 g

b
16.7 g

c
367 g

d
12.2 g

e
733 g

Please show work

Answers

Answer 12.2g is the answer

What is the mass of 2409793.03 particles of N2?

Answers

ANSWER



ANSWER

EVIDENCE

A student is drinking a cup of hot chocolate as they sit by a campfire on a chilly evening. They know that the cup of hot chocolate transfers thermal energy to the surrounding air. The heated air over their cup of hot chocolate expands and rises and is replaced by cooler, denser air.
This method of energy transfer is —

Answers

Answer:

A student is drinking a cup of hot chocolate as they sit by a campfire on a chilly evening. They know that the cup of hot chocolate transfers thermal energy to the surrounding air. The heated air over their cup of hot chocolate expands and rises and is replaced by cooler, denser air.

This method of energy transfer is

Explanation:

Answer:

radiation

Explanation:

radiation is when an existing heat source spreads heat to its surroundings

1. __N2 + __H2-> __NH3

2. __Fe + __HCl-> __H2 + __FeCl3

Answers

Answer:

N2+ 3H2-> 2NH3

2Fe + 6HCl -> 3H2 + 2FeCl3

Question 18 (5 points)
(03.06 MC)
Which statement is true about oxygen and rocks? (5 points)
a
Both are mixtures.
Both are pure substances.
Oxygen is a mixture and a rock is a pure substance.
d
Oxygen is a pure substance and rocks are mixtures.

Answers

Answer:

d. oxygen is a pure substance and rocks are mixtures

Answer:

A rock is a mixture and oxygen is a pure substance

Explanation:

Oxygen is just O O O O O O and rocks have many things in it like minerals, fossils and rock stuff. I'm not a geologist

what is 1/4 of 12 pleas i need help

Answers

Answer:

3

Explanation:

It's basically saying what number goes into 12 four times, I think.

What happened to your heart rate? What does the increased heart rate tell us about the circulatory system? Why do you think the circulatory system was pumping blood faster when you were running?
Pls help ill give brainliest

Answers

What the person above me said is correct

Which of the following is an example of a precipitate?
A: liquid evaporating into gas
B: a solid formed from a frozen liquid
C: a chunky solid formed from two liquids combining
D: a liquid solution that contains two substances

Answers

I think should be d. Please give me brainlest let me know if its correct or not okay thanks bye

9. How long will it take 120 grams of Strontium-90 to decay to 7.5 grams?
with steps pls​

Answers

Answer:

116 years

Explanation:

To solve this, we will use the half life equation;

A(t) = A_o(½)^(t/t_½)

Where;

A(t) is the amount of strontium left after t years;

A_o is the initial quantity of strontium that will undergo decay;

t_½ is the half-life of strontium

t is the time it will take to decay

We are given;

A(t) = 7.5 g

A_o = 120 g

From online values, half life of strontium-90 is 29 years. Thus, t_½ = 29

Thus;

7.5 = 120 × ½^(t/29)

Divide both sides by 120 to get;

7.5/120 = ½^(t/29)

0.0625 = ½^(t/29)

In 0.0625 = (t/29) In ½

-2.772589 = (t/29) × (-0.693147)

(t/29) = -2.772589/(-0.693147)

t/29 = 4

t = 29 × 4

t = 116 years

Which particle diagram represents a mixture?

( i hope you can read it)

Answers

the 3rd diagram is a mixture because it has 2 substances

The diagram of the mixture is the third diagram

Explanation:

A substance that only has one kind of atom is known as an element.The element cannot be broken down further into simple substances by any physical means.A substance that only has more than one kind of atom is known as a compound.The compound can be broken down further into simple substances by chemical means.The compound has a fixed proportion of atoms of different elements.A substance that only has more than one kind of element or compound is known as a mixture.The mixture can be separated by physical means.

So, from this, we can conclude that from the given particle diagrams, the diagram of the mixture is the third diagram as it has one compound molecule and two atoms of a different element.

Learn more about element, compound, and mixture here:

brainly.com/question/184321?referrer=searchResults

brainly.com/question/1844804?referrer=searchResults

You push 100kg door with force of 200 with what force does the door push back on you

Answers

Answer:

for every action there is equal and oposite reaction so door als pushes us back with same force. ie;200N.

PLEASE HELP ME! The question is on the image! It’s about the mole

Answers

Ok the answer is the

chemistry between people is the stongest like mine and urs right?

Answers

Answer:

..sure....

Explanation:

Answer:

hmm i dont see it homie sike gimmi that bootiy

On any given day or night, what determines the visible phase of the moon

A. how much of the sunlit side of the moon is visible

B. the time of day or night that we look at the moon

C. how far the moon has rotated on its axis

D. how much of the moon is lit by the sun

Answers

Answer:

i think the answer is D if not its A

a compound consists of 81.8% C and 18.2% H by mass. What is its empirical formula?​

Answers

Answer:

Empirical formula of 81.8 carbon and 18.2 hydrogen

Steps

Find the empirical formula of a compound that has 81.8% of Carbon (C), 18.2% of Hydrogen (H).Divide by fractional component of each mole value: C=1.5354936431103, H=4.0709872862205Round to closest whole numbers: C=2, H=4 Combine to get the empirical formula: C2H4

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