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

What volume in liters of carbon dioxide will be produced by the reaction of 18.5 liters of oxygen gas at STP?
L CO2

C3H8(g) + 5 O2(g) --> 3 CO2(g) + 4 H2O(g)
**Report your answer to the correct number of significant digits!

Answers

Answer:

0.16 L

Explanation:

Step 1: Write the balanced equation

C₃H₈(g) + 5 O₂(g) → 3 CO₂(g) + 4 H₂O(g)

Step 2: Calculate the moles of CO₂ produced from 0.012 moles of O₂

The molar ratio of O₂ to CO₂ is 5:3. The moles of CO₂ produced are 3/5 × 0.012 mol = 0.0072 mol.

Step 3: Calculate the volume occupied by 0.0072 moles of CO₂ at standard temperature and pressure

At STP, 1 mole of CO₂ occupies 22.4 L.

0.0072 mol × 22.4 L/1 mol = 0.16 L

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name the main form of energy released by the reaction between hydrogen and oxygen inside a combustion engine

Answers

Answer:

When molecular hydrogen (H2) and oxygen (O2) are combined and allowed to react together, energy is released and the molecules of hydrogen and oxygen can combine to form either water or hydrogen peroxide . These two processes are represented by the two chemical equations shown at right.

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*WILL GIVE BRAINLIEST* Which of the following best approximates the percentages of sand, clay, and silt in a sandy loam? Use the soil texture table below to answer.

A. Sand 40
Clay 30
Silt 30

B. Sand 60
Clay 10
Silt 30

C. Sand 20
Clay 60
Silt 20

D. Sand 25
Clay 15
Silt 60

Answers

B
Answer: The answer is B

Two substances both exhibit hydrogen bonding. Substance A has a boiling point of 78.4ºC. Substance B has a boiling point of 100ºC. Which statement correctly compares the substances?(1 point)
A) Substance A has stronger bonds, and it takes more energy to undergo a phase change.
B)Substance B has stronger bonds, and it takes more energy to undergo a phase change.
C) Substance B has stronger bonds, and it takes less energy to undergo a phase change.
D) Substance A has stronger bonds, and it takes less energy to undergo a phase change.

Answers

Answer:

The answer is C

Explanation:

Just took the test

Hydrogen bonding is the intermolecular interaction that occurs due to electronegativity differences. Substance B has stronger bonds and requires more energy. Thus, option B is correct.

What is hydrogen bonding?

Hydrogen bonding is present in the water molecules that is because of the electronegativity differences and the dipole-dipole interaction. The hydrogen of the water molecule is bonded to the oxygen molecule.

The hydrogen bonding affects the boiling and the melting point of the substances as more energy are required to change the phase of the matter. So when substance B requires 100ºC than substance A (78.4ºC) it shows strong hydrogen bonding.

Therefore, option B. substance B has a strong hydrogen bond is correct.

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what percentage of oxygen is attributed fossil fuel combustion


A.43%


B.77%


C.4%


D.17%

Answers

Answer:

C. 4%

Explanation:

The answer is 4%

A 4.0 L balloon has a pressure of 406 kPa. When the pressure increases to 2,030 kPa, what is the volume? *
0.4 L
0.8 L
0.2 L
1 L

Answers

The new volume when pressure increases to 2,030 kPa is 0.8L

BOYLE'S LAW:

The new volume of a gas can be calculated using Boyle's law equation:

P1V1 = P2V2

Where;

P1 = initial pressure (kPa)P2 = final pressure (kPa)V1 = initial volume (L)V2 = final volume (L)

According to this question, a 4.0 L balloon has a pressure of 406 kPa. When the pressure increases to 2,030 kPa, the volume is calculated as:

406 × 4 = 2030 × V2

1624 = 2030V2

V2 = 1624 ÷ 2030

V2 = 0.8L

Therefore, the new volume when pressure increases to 2,030 kPa is 0.8L.

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CO 2 is an element. true or false

Answers

Answer: false

Explanation:

f this helps typically an element wont have a 2 next to it, to see if something is an element or compound check for the element on the periodic table and see if the structure or name matches the one given to you on the question. for example here it is Co2 on the periodic table it's simply written as Co

co2 or carbon dioxide is a  compound not an element, you can even check this on the periodic table

Answer:

true

Explanation:

co2 is carbon dioxide

Hope this helps.

Write the symbol for every chemical element that has atomic number less than 13 and atomic mass greater than 17.2 u.

Answers

I’m so sorry don’t know just need the points asap

How many species are known to be living on Earth?

Answers

Answer:

8.7 million species

Explanation:

Scientists have estimated that there are around 8.7 million species of plants and animals in existence.

How many carbon atoms are in 11.2 ML of C3H6O

Answers

1 mL = 0.815 g

11.2 mL = X

X = 11.2 × 0.815

= 9.128 g

mole = 9.128/58

= 0.157 mole

1 mole = 6.02 × 10^23 atoms

0.157 mol = x

X = 0.157/1 × 6.02 × 10^23

= 9.451 × 10^22 atoms of C

please to recheck answers to ensure they are correct

I really hope this helps

A quantity of HCL ( 1.5*10⁻³ M) is added to water at 25°C to increase the hydrogen ion concentration from 1*10⁻⁷ to 1.5* 10⁻³ moles per liter. What is the new hydroxyl ion concentration?

Answers

Do you have a paper?

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

Ionic bond occurs between two atoms that have different:
a) Electron
b)Size
c)Polarity
d)Energy
e)Charge​

Answers

Answer:

Ionic bond occurs between two atoms that have different:

a) Electron

Explanation:

according to the definition of ionic bond,

it is the electrostatic force of attraction that holds the two oppositely charged ions together and an ionic bond or electrovalent bond is formed when one atom gains electrons while the other atom loses electrons from its outermost level or orbit.

The N2O decomposition, 2 N2O (g) → 2 N2 (g) + O2 (g), is a zero order reaction that has a reaction rate constant of 2.00 × 10−3 M/s. Initially, 2.00 moles of N2O gas are infused into a 1.00 L vessel at 300. K.Calculate the pressure inside the vessel at 100. seconds after the start of the reaction. Temperature is held constant.

Answers

Answer:

2.00n2g

Explanation:

hope its attachments

If 3.31 moles of argon gas occupies a volume of 100 L what volume does 13.15 moles of argon occupy under the same temperature and pressure

Answers

Answer:

397 L

Explanation:

Recall the ideal gas law:

[tex]\displaystyle PV = nRT[/tex]

If temperature and pressure stays constant, we can rearrange all constant variables onto one side of the equation:

[tex]\displaystyle \frac{P}{RT} = \frac{n}{V}[/tex]

The left-hand side is simply some constant. Hence, we can write that:

[tex]\displaystyle \frac{n_1}{V_1} = \frac{n_2}{V_2}[/tex]

Substitute in known values:

[tex]\displaystyle \frac{(3.31 \text{ mol})}{(100 \text{ L})} = \frac{(13.15\text{ mol })}{V_2}[/tex]

Solving for V₂ yields:

[tex]\displaystyle V_2 = \frac{(100 \text{ L})(13.15)}{3.31} = 397 \text{ L}[/tex]

In conclusion, 13.15 moles of argon will occupy 397* L under the same temperature and pressure.

(Assuming 100 L has three significant figures.)

What is the function of the nervous system? What is the basic unit of the nervous system?

#Nova

Answers

Answer:

The basic unit of the nervous system is a nerve cell or neuron. The nervous system transmits signals between the brain and the rest of the body, this way, the nervous system's activity controls the ability to move, breathe, see, and think.




Explanation:

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why lysine is less basic than arginine

Answers

Answer:

Arginine is the most basic among them because it contains guanidine side group, −(CH2)4NHC(=NH)NH2, which is basic. Lysine has two amine groups, which makes it overall basic because of the second isolated amine group (−(CH2)4NH2). Histidine, on the other hand, contains imidazole group, which is also basic.

Explanation:

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Oxygen-15 decays through the release of a beta particle. Draw what the nucleus would look like after a beta particle is emitted. What element does it become?

Answers

When oxygen -15 nucleus undergoes beta emission, it is transformed into Fluorine - 15 nucleus.

Beta decay is said to occur when a neutron is converted to a proton. This process leads to the emission of en electron. The neutron - proton ratio decreases and the atomic number of the daughter nucleus is greater than that of the parent nucleus by one  unit.

Hence, when oxygen -15 nucleus undergoes beta emission, it is transformed into Fluorine 15 nucleus.

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The diagram shows two different methods for collecting the product of a reaction. Which setup would be better for collecting a soluble gas such as ammonia?

Answers

Answer:

The setup above is used to collect hydrogen gas

Both filtration and distillation are useful ,methods to purify or separate components of a mixture. To collect soluble gas such as ammonia the best method is distillation. Thus setup 2 is better for collection of solute.

What is distillation?

Distillation is the process of separation of compounds using  heat and condenser. The mixture is first boiled to the boiling point of solvent. When it is heated the solvent such as water passes from the beaker on which the mixture is taken.

The steam of the solvent is then cooled in the condenser tube and then liquid is collected to a second beaker. Therefore, the solute remains in the first beaker and can be collected.

Using filtration, we can only separate solution with insoluble solutes. Using filter paper the solid from the solution can be separated out.

First set up shows the filtration method  which is not applicable for collecting soluble gas like ammonia. Therefore, the second setup that is distillation is better to collect soluble gases.

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The discrepancy between results given by the van der Waals equation and the ideal gas law will increase as:

Answers

This question is recalling the behavior of real gases in contrast to ideal gases, defined by the van der Waals equation and the ideal gas law respectively, and a reason behind the increasing discrepancy is required.

In such a way, we can start by considering the attached picture in which the choices are shown and clearly, the answer is "as the polarity of the molecules increase".

The aforementioned can be explained with the concept of intermolecular forces, because ideal gas theory states that ideal gas molecules do not interact one to another, and, as the polarity of the molecules increase, these intermolecular forces increase their frequency and strength, and will lead to the formation of associations, which fail to be numerically modelled by simple equations of state such as van der Waals, Redlich-Kwong, Peng-Robinson, etc,.

These associations are, of course, thoroughly neglected by the ideal gas law whereas the ones included in the van der Waals equation, which are not the most reliable, merely attempt to approach this phenomenon, which cause the mentioned discrepancy. As an additional data, robust equations of state, such as CPA (cubic plus association) are able to provide reliable results when working with highly polar gases but turn out really tough to work with due to its mathematical complexity.

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https://brainly.com/question/13423552https://brainly.com/question/13201335

why do we need to study thermodynamics?

Answers

Knowledge of thermodynamics is required to design any device involving the interchange between heat and work, or the conversion of material to produce heat (combustion). Examples of practical thermodynamic devices: What is thermodynamics? The study of the relationship between work, heat, and energy

Pure substances can be classified into element and compound. Choose the
CORRECT pair(s).
I Diamond - element
II Salt - compound
III Sugar solution - element

I and Il only
I only
II and III only
III and III

Answers

I and ll only
Diamond : mostly made of carbon (C) so element
Salt: made of sodium ions and chloride ions (NaCI) so coumpound

Which muscles is most important to you and why?

Answers

Answer:

cardiac muscle

Explanation:

because they help the heart to pump blood to all parts of the body

Answer:

Muscle is also very important to everyone because we need our muscles to survive. The HEART is the strongest muscle in our body and is always looking to get stronger. Muscles enable us to be active and exercise. Our strength comes for our muscles and how much they are used.

Explanation:

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ou dissolve a 2.50 g penny in 50.0 mL of HNO3. After reacting overnight, you dilute the blue solution to a volume of 100 ml. You test a sample of this solution, and find that it has an absorbance of 0.12 abs at 635 nm. i Calculate the concentration of Cu

Answers

This question is describing an spectrophotometry experiment in which the concentration of copper(II) ions has to be determined when 2.50 g of a copper-rich penny is reacted with 50.0 mL of nitric acid. In addition, the absorbance of a sample of the solution turned out to be 0.12 at 635 nm, so that the concentration was estimated as 12.8 g/L.

First of all, we must recall the Beer's law that can be written as follows:

[tex]A=ebC[/tex]

Whereas A is the absorbance of the sample, e the molar absorptivity, b the cuvette's path and C the concentration. However, this problem is not providing sufficient information to calculate the required concentration, however, similar absorbance experiments have graphed (absorbance vs concentration) calibration curves exhibiting trendlines as the one shown below:

[tex]y=0.009647x-0.003655[/tex]

Thus, since y stands for the absorbance and x for the concentration but in g/L not M (mol/L) for those experiments, we can set y equal to 0.12 so we solve for x as the concentration of the copper(II) ions in the sample:

[tex]y=0.009647x-0.003655\\\\x=\frac{0.12+0.003655}{0.009647}\\\\x=12.8g/L[/tex]

Nevertheless, it would be great if you come up with your own trendline, having clear the units for the absorbance vs concentration graph and thus double check your results because the data was not enough for the time being.

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(Beer's law and trendlines) https://brainly.com/question/5093710(Spectrophotometry) https://brainly.com/question/14467788

According to Dalton's atomic theory, atoms
a: of different elements combine in simple whole-number ratios to form compounds
b: can be divided into protons, neutrons, and electrons
c: of all elements are identical in size and mass
d: can be destroyed in chemical reactions

Answers

According to Dalton's atomic theory, atoms of different elements combine in simple whole-number ratios to form compounds.

DALTON'S ATOMIC THEORY:

As the name implies, Dalton's atomic theory is a theory proposed by an English scientist named John Dalton in the 1900's.

The Dalton's atomic theory is composed of five main parts, which are as follows:

All matter is comprised of tiny, definite particles called atoms.Atoms are indivisible and cannot be destroyed.All atoms of a particular element are identical in size and weight.Atoms of different elements contain different mass.Atoms of different elements combine in fixed whole-number ratios when forming compounds.

Therefore, in accordance to Dalton's atomic theory, atoms of different elements combine in simple whole-number ratios to form compounds.

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Which element gives up its valence electrons most readily?
Bi
Fr
Be
Ar

Answers

Answer:

Fr

Explanation:

I took the test

what is the chemical formula of copper (ii) hyddroxide

Answers

Answer:

Cu(OH)₂

Explanation:

Hope that helps

Answer: The chemical formula is Cu(OH)₂

Please help help helpppppppp

Answers

1. Magnesium atoms also have a slightly smaller radius than sodium atoms, and so the delocalised electrons are closer to the nuclei.
2. Sodium has higher melting point than potassium because of stronger metallic bonding .
3. Potassium are very soft metal can be very easily cut with a knife
4. Increase of resistance in metals. Therefore the mobility of electrons decreases and causes decrease in conductivity.
5.To increase strength, increase corrosion resistance, or reduce costs.
6. All metals have low ionization energies and are relatively electropositive, and so they lose electrons fairly easily.
7. All the group 1 metals are reactive, but they get more reactive as you go down the group, so potassium is more reactive than sodium.

A student wants to determine the melting point of water as part of an investigation into the strength of electrostatic forces. The student considers determining the freezing point of water instead. Is this a valid option?

Answers

According to the forces of attraction freezing point and boiling point of water are different and are not related to  strength of electrostatic forces.

What are forces of attraction?

Forces of attraction is a force by which atoms in a molecule  combine. it is basically an attractive force in nature.  It can act between an ion  and an atom as well.It varies for different  states  of matter that is solids, liquids and gases.

The forces of attraction are maximum in solids as  the molecules present in solid are tightly held while it is minimum in gases  as the molecules are far apart . The forces of attraction in liquids is intermediate of solids and gases.

The physical properties such as melting point, boiling point, density  are all dependent on forces of attraction which exists in the substances.

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How many atoms of copper in 3. 11 g of copper

Answers

Atomic weight of copper = 63.5 g1 mole of copper contains = 63.5g = 6.023 × 10²³ atoms of copper1 g of copper contains[tex] = \frac{ 6.023 \times 10²³}{63.5} [/tex]= 9.4 × 10²¹ atomsTherefore, 3.11g of copper contains[tex] = 3.11 \times 9.4 \times {10}^{21} \\ [/tex]= 29.234 × 10²¹ atoms

Hope you could get an idea from here.

Doubt clarification - use comment section.

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