How many moles does 205 g of helium,He, contain ?

Answers

Answer 1

Answer:

4.002602

Explanation:

Seems Am Converting Between Grams Helium And Mole.

Answer 2
No. of moles = mass / relative molecular mass
n = m / Mr
n = 205 g / 4 g/mol
n = 51.25 mol

Related Questions

At what stage of development are fish the most vulnerable?

Answers

Answer:

child stage.

Explanation:

they are more vubnlerabke at that stage

Check all of the following below which describe experimental errors that would affect the percent chloride you report in your experimental results: ____________
a) The solid product was wet when you weighed the final mass
b) You added excess silver nitrate into the reaction mixture
c) The liquid collected from the filtration was cloudy
d) The transfer from the reaction beaker to the filter funnel was imperfect (you lost some of the reaction solution or some was left in the beaker)
e) Extra water was used to dissolve the original unknown solid

Answers

The options that describe the experimental errors that would affect the percent of chloride reported are:

B (You added excess silver nitrate into the reaction mixture) and D (The transfer from the reaction beaker to the filter funnel was imperfect).

While performing experiments, there are some errors that occur which are generally known as experimental errors.

These experimental errors are the difference between the true measurement and what we measured.

There are three types of experimental errors they include:

systematic,

random, and

human error.

Human errors occur due to carelessness of the observer.

Examples are:

when you added excess silver nitrate into the reaction mixture

when the transfer from the reaction beaker to the filter funnel was imperfect due to lost of some of the reaction solution.

Therefore, the options describe the experimental errors that would affect the percent of chloride reported are B and D.

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what is the mass in g of 7.009 x 10^21 molecules of Pl3?

Answers

I have completed the problem

Consider the gas phase reaction 4HCl + O2 → 2Cl2 + 2H2O. What volume of chlorine gas at STP can be prepared from the reaction of 600. mL of gaseous HCl, measured at STP, with excess oxygen?
a. 150 mL b. 267 mL c. 300 mL d. 425 mL e. 600 mL

Answers

Answer:

c

Explanation:

Check the box under each molecule in the table below that is an isomer of this molecule:

Answers

The branched alkanes in boxes two and three all have molecular formula C6H14 and are isomers of the compound shown.

Isomers are compounds that has the same molecular formula but different structural formulas. Hence, isomers of compounds can be represented by the same molecular formula since they contain the same number of each atom.

The molecule shown has molecular formula C6H14. The branched alkanes in boxes two and three all have molecular formula C6H14 and are isomers of the compound shown.

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The effect of a catalyst is to: change the stoichiometry of the reaction. lower the activation energy of a reaction whereby making it easier for the reactants to get over the energy hump. change the position of the equilibrium. increase the number of collisions between reactants. increase the temperature of the reactants whereby more products are forme

Answers

The effect of a catalyst is

Option B(lower the activation energy of a reaction whereby making it easier for the reactants to get over the energy hump)What is a catalyst

A catalyst allows an alternative reaction pathway that leaves activation energy than the uncatalysed reaction. This does not change the frequency of collision.

Frequency of collision

Frequency of collision depend upon concentration of reactant temperatures

Catalyst on activation energy

Hence, catalyst lowers the activation energy of reaction thereby making it easier for the reactant to get over the energy hump.

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what is the wavelength of a photon emitted when an electron jumps from n=2 to n= 1 energy level of a single ionized helium atom ?​

Answers

Answer:

I hope it help you the wavelength is 1.9130E-28

Sound travels from a phone speaker to the ear of the person listening to the call. Sound waves are modeled by the image below. 1) What do the dots in the image represent? 2) How do sound waves travel through air to a person’s ear?

Answers

Answer:

Remember the black and red dots represented in the below animation are not molecules. They are just markers enabling us to visualize the local displacement of air particles and so, the rise and fall of pressure within the wave medium.

The air is made up of many tiny particles. When sound is created, the air particles vibrate and collide with each other, causing the vibrations to pass between air particles. The vibrating particles pass the sound through to a person's ear and vibrate the ear drum. Light travels much faster than sound through air.

Explanation:

What is the correct form of the equilibrium constant for the reaction of hydrogen and oxygen to form water? The equation is:

2H 2( g) + O 2( g) ⇌ H 2O( g)


Kc = ([H2O]/[O2] [H2])

Kc = ([H2O]/[O2] [H2]2)

Kc = ([H2O]/[O2] [H22])

Kc = ([H2O]2/[O2] [H22])

Kc = ([H2O]/[O2] [2H2])

Answers

Kc = ([H2O]/[O2] [H2]2

Serena mixed two samples together: a gray solid that smells like flowers and a gray solid that smells like bleach. She analyzed the results and found two ending substances. One of the ending substances was a white solid. This ending substance is made up of the repeating group of atoms shown above. Which of the diagrams to the left shows the repeating groups of atoms that make up the samples Serena mixed together?

Answers

The diagrams that shows the repeating groups of atoms that make up the samples which were mixed together is option D.

A chemical reaction is said to have occurred when there a rearrangement of atoms in a substance. This rearrangement of atoms in the substance leads to the formation of new substances.

In this case, we must note that the combination of reactants to be chosen must posses the atoms shown as part of the one of the end substance. The only option that satisfies this requirement is option D.

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Answer:D

Explanation:DDDDD

Alguien saber esto? Literal no se este material

Answers

Answer:

2. 389.15K , 3. 229.15K

Explanation:

K-273.15 = °C

Describe four characteristics of S-block elements​

Answers

1. s block elements have spherical s orbital as

their outermost orbital.

2. Since s orbital can accommodate a maximum of 2 electrons, each one of these elements have 1 or two electrons.

3. These s electrons are lost very easily to form

monopositive ions by Isoing one electron in the

outermost orbital or dipositive ions by losing 2

electrons.

4. They have low ionisation potentials and low electronegativities.

5. They are good conductors of heat and electricity, excepting H2 and He.

6. They are silvery, shiny metallic substances, (with the exception of hydrogen and helium which gaseous nonmetals).

7. They are malleable and ductile, i.e., we can

make sheets and wires from them, (exception:

H2, He)

8. They readily form ionic salts with most nonmetals.

hope it helps plzzz mark as brainliest

which type of element pairs can form ionic bonds

Answers

Answer:

Between metal and nonmetal ion's

Explanation:

for example, sodium (Na),a metal and a chloride (Ci

Brainliest for best answer

Answers

b is answer

Explanation:

please follow me

Answer:

B is the answer

Explanation:

A is incorrect as there is 2 O2 on the RHS while there is only 1 O2 on one side

B is correct as it is going through a process called combustion and I don't feel like explaining it is too long T^T

C is incorrect as the 3 results in multiply N (3 Nitrogen) while there is only one N2

D is definitely incorrect -.-

Hope this helps

(P.S. I lost a lot of my brain cells x-x)

A quantity of 1.922 g of methanol (CH3OH) was burned in a constant-volume bomb calorimeter. Consequently, the temperature of the water rose by 4.20 Ce … lsius. If the heat capacity of the bomb plus water was 10.4 kJ/degree Celsius, calculate the molar heat of combustion of methanol

Answers

The formula for calculating the amount of energy or heat released is:

ΔH = C ΔT

where ΔH is heat of combustion, C is heat capacity, while ΔT is change in temperature

ΔH = 8.69 kJ / °C * (5.14°C)

ΔH = 44.67 kJ

Then we calculate the moles of CH3OH which has molar mass of 32.04 g/mol:

moles = 1.922 / 32.04 = 0.05999 mol

SO the molar heat of combustion is:

ΔHm = 44.67 kJ / 0.0599875 mol

ΔHm = 744.60 kJ / mol

the weak base ionization constant (ka) for h2c2o4 is equal to what?

Answers

The acid ionization constant is the quantitative measure of the acidic strength. For oxalic acid, Ka = [H⁺] [HC₂O₄⁻] / [H₂C₂O₄]

What is acid dissociation?

Acid dissociation (Ka) is the ratio of the concentration of the conjugate base and hydrogen ion to the concentration of the chemical.

Oxalic acid is a weak acid and gets dissociated as:

H₂C₂O₄ ⇌ H⁺ + HC₂O₄⁻

or

HC₂O₄⁻ ⇌ H⁺ + C₂O₄²⁻

The acid ionization constant for the reactant and the product is given as:

Ka = [H⁺] [A⁻] / [HA]

Ka = [H⁺] [HC₂O₄⁻] / [H₂C₂O₄]

Therefore, the ionization constant for oxalic acid is given as Ka = [H⁺] [HC₂O₄⁻] / [H₂C₂O₄]

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what is the correct sequence of stages in cellular respiration

Answers

Answer:

Explanation:

Glycolysis

Pyruvic acid oxidation

Curbs cycle or citric acid cycle.

Respiratory chain.

Have a great night!

1. How does the figure below illustrate Hund's rule?

Answers

Answer:

it indicates that the lower orbitals are filled first and they have the maximum number of electrons compared to the higher orbitals


Help i dont get it

Answers

Answer:

2. Products; FeCl2 and H2S

Reactants; FeS and HCl

3. a) 36g of water

b) 64g of oxygen

If there is direct variation and y=75 when x=25, find x when y=48.


A. x=16

B. x=10

C. x=12

D. x=14

Answers

x = ky where k is a constant

first u find k so :
25 = k * 75
25/75 = k
k = 1/3

now when y = 48 just substitute the values
x = ky
x = 1/3 * 48
x = 16

the answer is A) x=16

If there is direct variation and y=75 when x=25,when y=48 X = 16. Therefore, option A is correct.

What is direct variation ?

link between two variables that can be described mathematically by an equation where one variable equals a constant multiplied by the other. For instance, the constant of variation is k = = 3 if y varies straight as x and y = 6 when x = 2. Consequently, y = 3x is the equation that describes this direct variation.

When x is not equal to zero, an equation of the form y = kx describes the linear function known as direct variation. When x is not equal to zero and k is a nonzero real number constant, the equation of the form xy = k describes the nonlinear function known as inverse variation.

x = ky

where k is constant

25 = k × 75

25 / 75 = k

k = 1 / 3

now when y = 48 then substitute the values

x = ky

x = 1 ÷ 3 × 48

x = 16

Thus, option A is correct.

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No matter what container it is in, a liquid usually:
A.has the same volume
B.has a different volume
C.has the same shape
D.has a different color

Answers

Answer:

A

Explanation:

A liquid will will have the same color, it will not have the same shape and its volume will always be constant because you are not creating mass.

Hope this helps!

Fe3+ and S2- write the formula for the compound that would be formed

Answers

The answer is Fe2S3

why is it important to use compound fixative in histology​

Answers

Answer:

To prevent autolysis (enzymes attack) as well as putrefaction (bacterial attack) of tissues.

napthalene combustion can be used to calibrate the heat capacity of a bomb calorimeter The heat of combustion of naphthalene is -40.1kj/g. When .8210g of naphthalene was burned in a calorimeter containing 1,000g of water, a temperature rise of 4.21C was observed. What is the heat capacity?

Answers

A bomb calorimeter with a heat capacity of 3.63 kJ/°C experiences a temperature rise of 4.21 °C when .8210 g of naphthalene is burned.

The combustion of naphthalene is used to calibrate the heat capacity of a bomb calorimeter.

What is a bomb calorimeter?

It is a device used to measure the change in the internal energy of a reaction.

To determine the heat capacity of the calorimeter (C), we need to follow a series of steps.

Step 1: Calculate the heat released by the combustion.

The heat of combustion of naphthalene is -40.1kJ/g and .8210g were burned.

Qcomb = -40.1kJ/g × .8210g = -32.9 kJ

Step 2: Determine the heat absorbed by the bomb calorimeter.

According to the law of conservation of energy, the sum of the heat released by the combustion and the heat absorbed by the bomb calorimeter is zero.

Qcomb + Qbomb = 0

Qbomb = -Qcomb = 32.9 kJ

Step 3: Calculate the heat capacity of the bomb calorimeter.

32.9 kJ were absorbed, part by the calorimeter itself and part by the 1,000 g (m) of water, whose specific heat capacity (c) is 4.18 J/g°C.

A temperature rise (ΔT) of 4.21 °C is observed. We can determine the heat capacity of the bomb calorimeter (C) using the following expression.

Qbomb = Qcal + Qwater

32.9 kJ = C × ΔT + c × m × ΔT

32.9 kJ = C × 4.21 °C + (4.18 × 10⁻³ kJ/g.°C) × 1,000 g × 4.21 °C

C = 3.63 kJ/°C

A bomb calorimeter with a heat capacity of 3.63 kJ/°C experiences a temperature rise of 4.21 °C when .8210 g of naphthalene is burned.

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What is the pH when 30.0 ml of 0.005 M HF is mixed with 15.0 ml of 0.01 M NaOH?​

Answers

Answer:

7.36

Explanation:

my teacher said that was the right answer

The diagram below shows the reaction between iron oxide and carbon that produces iron and carbon dioxide. The reaction takes place in a closed system. What is true about the carbon atoms in the reaction? A. The mass of carbon atoms in the reactants is the same as the mass of carbon atoms in the products. B. The total mass of the carbon atoms is the same as the total mass of the iron atoms. C. The mass of the carbon atoms increases between the reactants and the products of the reaction. D. The total mass of the carbon atoms is the same as the total mass of the oxygen atoms.

Answers

Answer:

A

Explanation:

The trick here is to know what the conservation of mass means.

It means that no matter what happens and how much change there is, the mass of the carbons on the reactants = the mass of the carbons on the products.

That's exactly what A says.

the name of this fatty acid is caprylic acid :

CH3(CH2)6COOH ??

Answers

Explanation:

Are you asking if that is the formula for caprylic acid? The answer is yes. CH₃(CH₂)₆COOH is the correct formula.

Caprylic acid, also known as C8 or octanoic acid, is a medium chain triglyceride (MCT) primarily found in coconut oil. It's the shortest of all the MCTs, making it the easiest for the body to break down into fuel. Once it is consumed, C8 is instantly digested and converted into ketones.

if one gram of sulphur dioxide contains x molecules what will be the number of molecules in 1g of methane

Answers

The ratio of molecules in sulphur dioxide and methane will be the same as the ratio of their moles. So, first of all we should find out the number of moles of sulphur dioxide in 1 gram of sulphur dioxide in 1 gram of sulphur dioxide, and the number of moles of methane in 1 gram of methane. This can be done as follows :

(i) The molecular formula of sulphur dioxide is [tex]SO_{2}[/tex]

So, [tex]1[/tex]  mole of [tex]SO_{2}[/tex] = [tex]Mass[/tex] [tex]of[/tex] [tex]2'O'[/tex]

[tex]=32+2*16[/tex]

[tex]= 64[/tex] grams

Now, [tex]64g[/tex] of sulphur dioxide [tex]= 1[/tex] mole

So, [tex]1g[/tex] of sulphur dioxide = [tex]\frac{1}{64}[/tex] mole

Thus, we have [tex]\frac{1}{64}[/tex] mole of sulphur dioxide and it contains molecules in it. Now, since equal moles of all the substance contain equal number of molecules, therefore, [tex]\frac{1}{64}[/tex] mole of methane will also contain x molecules of methane.

(ii) Molecular formula of methan is [tex]CH_{4}[/tex]

So, 1 mole of [tex]CH_{4}[/tex]  = Mass of C + Mass of 4 H

[tex]=12+4*12[/tex]

Now, 16g of methane = 1 mole

So, 1 g of mathane = [tex]\frac{1}{16}[/tex] mole

We know that:

[tex]\frac{1}{64}[/tex] mole of methane contains = x molecules

So, [tex]\frac{1}{16}[/tex]  mole of contains will contain =[tex]\frac{x*64}{16}[/tex] molecules

=[tex]4x[/tex] molecules

Pls help plz answer this question

Answers

Answer:

A) Carbon dioxide and Oxygen

Explanation:

Percentage of gases in the Planet's atmosphere:

Carbon dioxide = 4 % Nitrogen = 72 % Oxygen = 24 %

Percentage of gases in the Earth's atmosphere:

Carbon dioxide = 0.036 % (traces)Nitrogen = 78 % Oxygen = 21 %

___________________

On observing the percentage composition of the atmospheres of the two Planets, we get:

The newly discovered planet has more percentage of Oxygen than The Earth. Percentage of Carbon dioxide is more in the planet than in the EarthNitrogen is less in the planet than in the Earth.

___________________

Answer:

What's asked is the name of the gases that are in higher amounts in the atmosphere of the newly discover planet

Therefore,

A) Carbon dioxide and Oxygen

Nitrogen H2 has :

a)Double bonds

b)Bounded by 6 electrons

c) The bond is ionic

d) Can forms der Waals bonds

e) B& d​

Answers

Answer:

the bond is ionic

Explanation:

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