At 298 K and 1 atm which noble gas has the lowest density? Why?

1) Ne

2) Kr

3) Xe

4) Rn

Answer:

The best and most correct answer among the choices provided by your question is the fourth choice.

The data explains that sodium atoms hardly ever form 2+ ions.

I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!

Explanation:

Answer: 16.21

Explanation:

A student measures the length of two pieces of paper as 8.21 in and 8.0 in. the total length is 16.21 with 4 significant figures.

The significant figures or digits are the form of scientific methd which represent the digit from zero to nine and use when the value is uncertain where starting zeros are not significant and decimal is also not a significant figure.

In the given value the total is 16.21 with 4 significant figures with it has 4 significant digits and the decimal with it is not significant after adding from which the respective value is here.

Therefore,  with 4 significant figures where the student measures the length of two pieces of paper as 8.21 in and 8.0 in. the total length is 16.21.

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Answer:

The answer is B

Explanation:

I had the same question and I chose B and it was correct.

Answer:

B. Carbon needs more than just three bonds to reach a noble gas

Explanation:

PLATO ANSWER

PLATO EXPLANATION-

Each hydrogen atom can make only one bond, but a carbon atom needs four bonds to be stable. Therefore, three hydrogen atoms are not enough for the carbon atom to make four bonds.

Answer:

M = 17 M

Explanation:

Given data:

Mass of sodium hydroxide = 678.57 g

Volume of solution = 1.00 L

Molarity  of solution = ?

Solution:

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

Number of moles of sodium hydroxide:

Number of moles = mass/molar mass

Number of moles = 678.57 g /40 g/mol

Number of moles = 17 mol

Molarity:

M =  17 mol/1.00 L

M = 17 mol/L

M = 17 M

Answer:

false

Explanation:

"When a metal reacts with hydrogen carbon dioxide gas is produced" statement is false.

A chemical reaction is a representation of symbols of the elements to indicate the amount of substance and moles of reactant and product.

Generally, metals do not react with hydrogen. But some metals like sodium, potassium, calcium and magnesium force the hydrogen atom to accept the electrons given by these elements and form salt-like ionic solid compounds called metal hydrides.

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We are given:

Mass of NaCl in the given solution = 22.3 grams

Volume of the given solution = 2 L

Number of Moles of NaCl:

We know that the number of moles = Given mass / Molar mass

Number of moles = 22.3 / 58.44 = 0.382 moles

Molarity of NaCl in the Given solution:

We know that Molarity of a solution = Moles of Solute / Volume of Solution(in L)

Molarity = 0.382 / 2

Molarity = 0.191 M

Answer:

3.64g

Explanation:

Given parameters:

Mass of NH₃  = 18.1g

Mass of Cu₂O  = 90.4g

Unknown:

Limiting reactant  = ?

Mass of N₂ formed  = ?

Solution:

The reaction equation is given as:

       Cu₂O + 2NH₃ → 6Cu + N₂ + 3H₂O

The limiting reactant is the one in short supply in the reaction. Let us find the number of moles of the given species;

  Number of moles = [tex]\frac{mass}{molar mass}[/tex]  

Molar mass of Cu₂O = 2(63.6) + 16  = 143.2g/mol

Molar mass of NH₃  = 14 + 3(1) = 17g/mol

Number of moles of Cu₂O = [tex]\frac{18.1}{143.2}[/tex]   = 0.13moles

Number of moles of NH₃   = [tex]\frac{90.4}{17}[/tex]   = 5.32moles

  From this reaction;

       1 mole of  Cu₂O combines with 2 mole of NH₃

So   0.13moles of  Cu₂O will combine with 0.13 x 2 mole of NH₃

                                              = 0.26moles of NH₃

Therefore, Cu₂O is the limiting reactant. Ammonia is in excess;

Mass of N₂;

   Mass = number of moles x molar mass

    1 mole of Cu₂O  will produce 1 mole of N₂

    0.13 mole of Cu₂O  will produce 0.13 mole of N₂

    Mass  = 0.13 x (2 x 14) = 3.64g

Answer:

[tex]T_f=26.7\°C[/tex]

Explanation:

Hello.

In this case, when two substances at different temperature are placed in contact in an isolated container, we can say that the heat lost by the hot substance is gained by the cold substance. In such a way, since granite is at 76.0 °C and water at 22.0 °C we infer granite is hot and water is cold, so we write:

[tex]Q_{granite}=-Q_{water}[/tex]

In terms of mass, specific heat and change in temperature, we write:

[tex]m_{granite}C_{granite}(T_f-T_{granite})=-m_{water}C_{water}(T_f-T_{water})[/tex]

Thus, since the temperature is the same for both substance, we can solve for it as shown below:

[tex]T_f=\frac{m_{granite}C_{granite}T_{granite}+m_{water}C_{water}T_{water}}{m_{granite}C_{granite}+m_{water}C_{water}}[/tex]

By plugging in each variable, we obtain:

[tex]T_f=\frac{11.1g*0.790\frac{J}{g\°C} *76.0\°C+22.0g*4.18\frac{J}{g\°C} *22.0\°C}{11.1g*0.790\frac{J}{g\°C} +22.0g*4.18\frac{J}{g\°C}}\\\\T_f=26.7\°C[/tex]

Best regards!

Moles of MgF₂ : 1.2 x 10⁻⁴

Maybe the complete question is like this

A student prepares 100. mL of a saturated solution of MgF2 by adding 0.50 g of solid MgF2 to 100. mL  of distilled water at 25°C and stirring until no more solid dissolves. (Assume that the volume of the  undissolved MgF2 is negligibly small.) The saturated solution is analyzed, and it is determined that [F−] in  the solution is 2.4 × 10−3 M.

The dissociation reaction of MgF₂

MgF₂(s)⇒ Mg²⁺(aq)+2F⁻(aq)

mol ratio MgF₂ : F⁻ = 1 : 2

mol of F⁻ in 100 ml solution :

[tex]\tt mol=M\times V\\\\mol=2.4\times 10^{-3}\times 0.1=2.4\times 10^{-4}[/tex]

mol MgF₂ :

[tex]\tt \dfrac{1}{2}\times 2.4\times 10^{-4}= 1.2\times 10^{-4}[/tex]

Answer:

5.00 moles O₂

General Formulas and Concepts:

Chemistry - Atomic Structure

Explanation:

Step 1: Define

3.01 × 10²⁴ molecules O₂

Step 2: Convert

[tex]3.01 \cdot 10^{24} \ mc \ O_2(\frac{1 \ mol \ O_2}{6.022 \cdot 10^{23} \ mc \ O_2} )[/tex] = 4.99834 moles O₂

Step 3: Check

We are given 3 sig figs. Follow sig fig rules and round.

4.99834 moles O₂ ≈ 5.00 moles O₂

Alcohol is both a Depressant and a Muscle Relaxer. Therefore the answer would be both!

Hope this helps :)

The work energy of this process : 2337.298 J

The laws of thermodynamics 1 state that: energy can be changed but cannot be destroyed or created  

ΔU=Q-W

Q=m.c.Δt

[tex]\tt Q=8.85\times 2.650\times 63.2=1482.198~J[/tex]

the work (W) :

[tex]\tt W=Q-\Delta U\\\\W=1482.198-(-855.1)=2337.298~J[/tex]

Answer:

0.44L

Explanation:

Given parameters:

  Initial volume  = 0.75L

  Initial temperature  = 25°C  = 273 + 25 = 298K

  Final temperature  = -100°C  = 273 + (-100) = 173K

Unknown:

New volume of the balloon = ?

Solution:

According to Charles's law;

   "the volume of a fixed mass of a gas varies directly as its absolute temperature if the pressure is constant".

Mathematically;

    [tex]\frac{V_{1} }{T_{1} }[/tex]   =  [tex]\frac{V_{2} }{T_{2} }[/tex]  

  V and T are temperature values

  1 and 2 are the initial and final states

Insert the parameters and solve;

   [tex]\frac{0.75}{298}[/tex]   = [tex]\frac{V_{2} }{173}[/tex]  

    298V₂   = 129.75

           V₂  = 0.44L

Answer:

-114kJ mol-1

Explanation:

Definition of the enthalpy change of neutralization: the energy released with the formation of 1 mole of water when neutralization takes place between an acid and a base.

Since both reactions yield the same number of moles of water, the answer should be -114kJ mol-1.

The statement for the enthalpy change of reaction 2 is "-114 kJ"

The change in enthalpy (ΔH) is a quantity of heat of a system. The enthalpy change is the amount of heat that enters or exits a system during a reaction.

One equivalent of hydrogen ions is neutralised with one equivalent of hydroxide ions in the reaction 1,

NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)

The change in enthalpy is given as -114 kJ.

Two equivalents of hydrogen ions are neutralised with two equivalents of hydroxide ions in the reaction 2,

Ba(OH)2 + H2SO4 (aq) → BaSO4 (s) + 2H2O (l)

But, that primary ionic reaction is same for both the reaction in which hydrogen ion combines with hydroxide ion to generate a water molecule. So, the enthalpy change of reaction 1 would be exactly same as for reaction 2.

The neutralization enthalpy comes out to be -114 kJ.

Hence the correct answer is -114 kJ.

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Answer:

If an atom gains or loses an electron, it bacomes an ion. An atom that gains a negative electron, it becomes a negative ion. If it loses an electron it becomes a positive ion

Explanation:

A lithium atom has 3 protons and 3 electrons. It can lose one of its electrons, making it an ion. It now has more positive protons than electrons so it has an overall positive charge. Therefore it is a positive ion.

A fluorine atom will tend to gain, rather than lose, an electron. By gaining a negative electron, it has an overall negative charge. It has become a negative ion.

Percent by mass : 4.10⁺³%

The concentration of a solution can be expressed in units such as molarity, normality, mass percent, volume percent etc.

[tex]\tt \%mass=\dfrac{mass~solute}{mass~solution}\times 100\%[/tex]

mass solute= mass of NaOH  

mass of NaOH :

[tex]\tt 0.001~mol/L\times 1~L\times 40~g/mol=0.04~g[/tex]

mass solution = 1000 g

% mass :

[tex]\tt \dfrac{0.04}{1000}\times 100=4.10^{-3}\%[/tex]

The percent by mass concentration of NaOH in the given solution is approximately 0.004%.

To calculate the percent by mass concentration of NaOH, we must find the mass of NaOH in solution.

First, we determine how many moles of NaOH are present in the solution:

Molarity (M) is calculated as moles of solute per liter of solution.

1 L = 0.001 M = mole of NaOH

We rearrange the equation to find that one mole of NaOH is equal to 0.001 moles.

Mass of NaOH = moles of NaOH * molar mass of NaOH

Mass of NaOH = 0.001 mol * 40.00 g/mol

Mass of NaOH = 0.04 g

The mass of the solution is 1000 g which is given in the question.

Percent by mass concentration of NaOH = (mass of NaOH / mass of solution) * 100%

Percent by mass concentration of NaOH = (0.04 g / 1000 g) * 100%

Percent by mass concentration of NaOH = 0.004%

Hence, the percent by mass concentration of NaOH in the given solution is approximately 0.004%.

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C : 52.2%, H : 13.1%, O:34.7%

The empirical formula is the smallest comparison of atoms of compound forming elements.  

A molecular formula is a formula that shows the number of atomic elements that make up a compound.  

(empirical formula) n = molecular formula  

11.5 g of Ethanol-C₂H₅OH contains 6.00 g of Carbon and 1.51 g of Hydrogen.

mass of Oxygen :

[tex]\tt 11.5-(6+1.51)=4~g[/tex]

Percent composition :

[tex]\tt \dfrac{6}{11.5}\times 100\%=52.2\%[/tex]

[tex]\tt \dfrac{1.51}{11.5}\times 100\%=13.1\%[/tex]

[tex]\tt \dfrac{4}{11.5}\times 100\5=34.7\%[/tex]

Answer:

1.5 × 10² mL

Explanation:

Step 1: Given data

Step 2: Calculate the final volume of the gas

For an ideal gas, we can calculate the final volume of the gas using Boyle's law.

P₁ × V₁ = P₂ × V₂

V₂ = P₁ × V₁/P₂

V₂ = 1.9 atm × 80 mL/1.0 atm

V₂ = 1.5 × 10² mL

Since the pressure decreased, the volume of the gas increased.

D. People with different goals can make contributions to scientific knowledge

Both Schwann and Virchow had different thoughts and ideas. Schwann wanted to understand how cells worked - Virchow wanted to know the origin of diseases. Different goals.

Answer:

D

Explanation:

I got it right on studyisland

Answer:

Explanation:

The mass of the bicycle can be found by using the formula

[tex]m = \frac{p}{v} \\ [/tex]

p is the momentum

v is the velocity

From the question we have

[tex]m = \frac{25}{2.5} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

compound

Explanation:

Answer:

The answer is compound

Explanation:

Answer:

46.32 mL

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated below:

2HNO₃ + Ca(OH)₂ —> Ca(NO₃)₂ + 2H₂O

From the balanced equation above,

The following data were obtained:

Mole ratio of the acid, HNO₃ (nA) = 2

Mole ratio of the base, Ca(OH)₂ (nB) = 1

Next, we shall write out the data obtained from the question. This includes:

Molarity of the acid, HNO₃ (Ma) = 0.181 M

Volume of the base, Ca(OH)₂ (Vb) = 25.1 mL

Molarity of the base, Ca(OH)₂ (Mb) = 0.167 M

Volume of the acid, HNO₃ (Va) =?

Finally, we shall determine the volume of the acid, HNO₃ as shown below:

MaVa/ MbVb = nA/nB

0.181 × Va / 0.167 × 25.1 = 2/1

0.181 × Va / 4.1917 = 2

Cross multiply

0.181 × Va = 4.1917 × 2

0.181 × Va = 8.3834

Divide both side by 0.181

Va = 8.3834 / 0.181

Va = 46.32 mL

Therefore, the nitric acid, HNO₃ required for the reaction is 46.32 mL

Answer:

Universe.

Explanation:

Biosphere is just a planet. Solar system contains planets and star. Galaxy holds multiple solar systems only. Universe hold everything, biospheres, solar systems, and galaxies. I hope this helps :D

Answer:

B.

Explanation:

A solar system is IN a galaxy. Its not A.

A Galaxy doesnt have other galaxies in it. Its not c

A biosphere is only referring to earth. its not D.

Therefore, it is B. A universe is everything in outer space including stars, planets, and galaxies.

Answer:

85,020 milligrams

Explanation:

Multiply the mass value by 1,000

Answer:

Watch Naruto that's the answer

Explanation:

Answer:

the answer is d. frequency

Answer:

Explanation:

no of molecules=5.65*10^21

NA=6.23*10^23

no of moles=no of molecules/avogadro number

no of moles=5.65*10^21/6.23*10^23

no of moles=9.07*10^-3

now we know that

no of moles=mass/molar mass

mass=no of moles*molar mass

mass=9.07*10^-3*89.06

mass=0.808 g

Answer:

Mass of CO₂ produced = 20.328 g

Oxygen is limiting reagent.

Explanation:

Given data:

Mass of C₂H₂ = 13.7 g

Mass of O₂ = 18.5 g

Mass of CO₂ produced = ?

What is limiting reagent = ?

Solution:

Chemical equation:

2C₂H₂ + 5O₂      →     4CO₂ + 2H₂O

Number of moles of C₂H₂:

Number of moles = mass /molar mass

Number of moles = 13.7 g/ 26.04 g/mol

Number of moles = 0.526 mol

Number of moles of O₂:

Number of moles = mass /molar mass

Number of moles = 18.5 g/ 32 g/mol

Number of moles = 0.578 mol

Now we will compare the moles of CO₂ with C₂H₂ and O₂

                      C₂H₂              :                CO₂

                           2                :                 4

                       0.526            :              4/2×0.526 = 1.052

                      O₂                  :                   CO₂

                        5                   :                     4

                      0.578             :                4/5×0.578 = 0.462

The number of moles of  CO₂ produced by O₂  are less thus oxygen will be limiting reactant.

Mass of CO₂ produced:

Mass = number of moles × molar mass

Mass = 0.462 mol × 44 g/mol

Mass = 20.328 g