What is the atomic mass for Helium (He)? Question 5 options: 8 2 3 4

Answer:

The volume that a mass of 47.2 g would occupy is 0.0334 L

Explanation:

Density is the property that matter, whether solid, liquid or gas, has to compress into a given space. Density is defined as the amount of mass it has per unit volume, that is, the ratio between the mass of a body and the volume it occupies:

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

This indicates that density is inversely proportional to volume: the smaller the volume occupied by a given mass, the higher the density.

In this case:

Replacing:

[tex]1.413 \frac{g}{mL}=\frac{47.2 g}{volume}[/tex]

Solving:

[tex]volume=\frac{47.2 g}{1.413\frac{g}{mL} }[/tex]

volume=33.40 mL

Being 1,000 mL= 1 L:

volume= 0.0334 L

The volume that a mass of 47.2 g would occupy is 0.0334 L

Answer:

Pentan-2-ol

Explanation:

On this reaction, we have a Grignard reagent (ethylmagnesium bromide), therefore we will have the production of a carbanion (step 1). Then this carbanion can attack the least substituted carbon in the epoxide in this case carbon 1 (step 2). In this step, the epoxide is open and a negative charge is generated in the oxygen. The next step, is the treatment with aqueous acid, when we add acid the hydronium ion ([tex]H^+[/tex])  would be produced, so in the reaction mechanism, we can put the hydronium ion. This ion would be attacked by the negative charge produced in the second step to produce the final molecule: "Pentan-2-ol".

See figure 1

I hope it helps!

Answer:

It has 2

Explanation:

The significant figures are 1 and 5!

Hope this helps:)

Answer:

there is one atom of oxygen and two atoms of hydrogen

Explanation:

Answer:

Following are the answer to this question:

Explanation:

For the reductive amination of its carbonyl group, amino acids could be synthesized by reducing ammunition, which can be synthesized in the given attachment file:

please find the attachment:

Answer:

0 g.

Explanation:

Hello,

In this case, since the reaction between methane and oxygen is:

[tex]CH_4+2O_2\rightarrow CO_2+2H_2O[/tex]

If 0.963 g of methane react with 7.5 g of oxygen the first step is to identify the limiting reactant for which we compute the available moles of methane and the moles of methane consumed by the 7.5 g of oxygen:

[tex]n_{CH_4}=0.963gCH_4*\frac{1molCH_4}{16gCH_4}=0.0602molCH_4\\ \\n_{CH_4}^{consumed}=7.5gO_2*\frac{1molO_2}{32gO_2}*\frac{1molCH_4}{2molO_2} =0.117molCH_4[/tex]

Thus, since oxygen theoretically consumes more methane than the available, we conclude the methane is the limiting reactant, for which it will be completely consumed, therefore, no remaining methane will be left over.

[tex]left\ over=0g[/tex]

Regards.

Answer:

-69 kJ

Explanation:

Step 1: Given data

Standard cell potential (E°cell): +0.24 V

Electrons involved (n): 3 mol

Step 2: Calculate the standard Gibbs free energy change (ΔG°) for the voltaic cell

We will use the following expression.

ΔG° = -n × F × E°cell

where,

F is Faraday's constant (96,485 C/mol e⁻)

ΔG° = -n × F × E°cell

ΔG° = -3 mol e⁻ × 96,485 C/mol e⁻ × 0.24 V

ΔG° = -69 kJ

Answer:

1. oxidation

2. reduction

3. oxidation

4. oxidation

Explanation:

Oxidation and Reduction in terms of hydrogen

Oxidation and Reduction in terms of Oxygen

Answer:

[tex]\large \boxed{\text{0.57 g/mL; 3.7 mL; 6.6 g; 0.366 g/mL}}[/tex]

Explanation:

1. Density from mass and volume

[tex]\text{Density} = \dfrac{\text{mass}}{\text{volume}}\\\\\rho = \dfrac{m}{V}\\\\\rho = \dfrac{\text{8.6 g}}{\text{15 mL}} = \text{0.57 g/mL}\\\text{The density is $\large \boxed{\textbf{0.57 g/mL}}$}[/tex]

2. Volume from density and mass

[tex]V = \text{9.7 g}\times\dfrac{\text{1 mL}}{\text{2.6 g}} = \text{3.7 mL}\\\\\text{The volume is $\large \boxed{\textbf{3.7 mL}}$}[/tex]

3. Mass from density and volume

[tex]\text{Mass} = \text{4.1 cm}^{3} \times \dfrac{\text{1.6 g}}{\text{1 cm}^{3}} = \textbf{6.6 g}\\\\\text{The mass is $\large \boxed{\textbf{6.6 g}}$}[/tex]

4. Density by displacement

Volume of water + object = 24.6 mL

Volume of water                = 12.8 mL

Volume of object               = 11.8 mL

[tex]\rho = \dfrac{\text{4.3 g}}{\text{11.8 mL}} = \text{0.36 g/mL}\\\text{The density is $\large \boxed{\textbf{0.36 g/mL}}$}[/tex]

Your drawing showing water displacement using a graduated cylinder should resemble the figure below.

Answer:

The acid reacts with the conjugate base producing more weak acid.

Explanation:

A buffer solution is defined as the mixture of a weak acid and its conjugate base or a weak base with its conjugate acid.

The acetic buffer, CH₃COOH/CH₃COO⁻, is in equilibrium with water as follows:

CH₃COOH(aq) + H₂O(l) ⇄ CH₃COO⁻(aq) + H₃O⁺

When an acid HX (Source of H₃O⁺) is added to the buffer, the reaction that occurs is:

CH₃COO⁻ + HX → CH₃COOH

In fact, this is the principle of the buffer:

An acid reacts with the conjugate base producing weak acid. And the weak acid reacts with a base producing conjugate base

If a small amount of acid is added to an acetic acid-sodium acetate buffer, the acid will react with the acetate ion from sodium acetate.

We have a buffer formed by acetic acid and sodium acetate.

A buffer is a solution used to resist abrupt changes in pH when an acid or a base is added.

They can be formed in 1 of 2 ways:

Our buffer is formed by a weak acid (acetic acid) and its conjugate base (acetate ion from sodium acetate).

When an acid (HX) is added, it is neutralized by the basic component of the buffer. The generic net ionic equation is:

H⁺ + CH₃COO⁻ ⇄ CH₃COOH

If a small amount of acid is added to an acetic acid-sodium acetate buffer, the acid will react with the acetate ion from sodium acetate.

Learn more about buffers here: https://brainly.com/question/24188850

Answer:

B) geminal diol

Explanation:

Hello,

In this case, considering the attached picture, you can see that the substance resulting from the hydrolysis of an aldehyde or a ketone is a geminal diol since the two hydroxyl groups are in the same carbon. Such hydrolysis could be carried out in either acidic or basic conditions depending upon the equilibrium constant.

Regards.

Answer:

Explanation:

50 HP = 50 x 746 watt

= 37300 watt

= 37300 J /s

heat produced in one hour = 60 x 60 x 37300 J

= 134280 x 10³ J

latent heat of vaporization = 2260 x 10³ J / kg .

for evaporation of water of mass 1 kg , 2260 x 10³ J of heat is required .

kg of water being evaporated by boiler per hour

= 134280 x 10³ / 2260 x 10³

= 59.41 kg

rate of production of steam

= 59.41 kg / hr .

Answer:

Solid sodium hydroxide dissolves in water to form an aqueous solution of ions.

NaOH(s) ⇌ Na+(aq) + OH–(aq) ΔH1 = ?

Solid sodium hydroxide reacts with aqueous hydrochloric acid to form water and an aqueous solution of sodium chloride.

NaOH(s) + H+(aq) + Cl–(aq) ⇌ H2O(l) + Na+(aq) + Cl–(aq) ΔH2 = ?

Solutions of aqueous sodium hydroxide and hydrochloric acid react to form water and aqueous sodium chloride.

Na+(aq) + OH–(aq) + H+(aq) + Cl–(aq) ⇌ H2O(l) + Na+(aq) + Cl–(aq) ΔH3 = ?

Answer:

There are no forces holding the gas particles together.

Explanation:

Answer:

a.

[tex]m_K=8.056gK\\ \\m_{Cl_2}=4.028gCl_2[/tex]

b.

[tex]m_{Cr}=10.51gCr\\ \\m_{O_2}=4.851gO_2[/tex]

c.

[tex]m_{Sr}=13.88gSr\\\\m_{N_2}=1.479gN_2[/tex]

Explanation:

Hello,

In this case, we proceed via stoichiometry in order to compute the masses of all the reactants as shown below:

a. [tex]2K+Cl_2\rightarrow 2KCl[/tex]

[tex]m_K=15.36gKCl*\frac{1molKCl}{74.55gKCl}*\frac{2molK}{2molKCl}* \frac{39.1gK}{1molK}=8.056gK\\ \\m_{Cl_2}=15.36gKCl*\frac{1molKCl}{74.55gKCl}*\frac{1molCl_2}{2molKCl}* \frac{70.9gCl_2}{1molCl_2}=4.028gCl_2[/tex]

b. [tex]4Cr+ 3O_2\rightarrow 2Cr_2O_3[/tex]

[tex]m_{Cr}=15.36gCr_2O_3*\frac{1molCr_2O_3}{152gCr_2O_3l}*\frac{4molCr}{2molCr_2O_3}* \frac{52gCr}{1molCr_2O_3}=10.51gCr\\ \\m_{O_2}=15.36gCr_2O_3*\frac{1molCr_2O_3}{152gCr_2O_3l}*\frac{3molO_2}{2molCr_2O_3}* \frac{32gO_2}{1molCr_2O_3}=4.851gO_2[/tex]

c. [tex]3Sr(s) + N_2(g) \rightarrow Sr_3N_2[/tex]

[tex]m_{Sr}=15.36gSr_3N_2*\frac{1molSr_3N_2}{290.86gSr_3N_2}*\frac{3molSr}{1molSr_3N_2}* \frac{87.62gSr}{1molSr}=13.88gSr\\\\m_{N_2}=15.36gSr_3N_2*\frac{1molSr_3N_2}{290.86gSr_3N_2}*\frac{1molN_2}{1molSr_3N_2}* \frac{28gN_2}{1molN_2}=1.479gN_2[/tex]

Regards.

Answer:

[tex]\large \boxed{1.503 \times 10^{23}\text{ molecules of Cu(OH)}_{2}}$}[/tex]

Explanation:

You must calculate the moles of Cu(OH)₂, then convert to molecules of Cu(OH)₂.

1. Moles of Cu(OH)₂[tex]\text{Moles of Cu(OH)}_{2} = \text{24.35 g Cu(OH)}_{2} \times \dfrac{\text{1 mol Cu(OH)}_{2}}{\text{97.562 g Cu(OH)}_{2}} = \text{0.2496 mol Cu(OH)}_{2}[/tex]

2. Molecules of Cu(OH)₂[tex]\text{No. of molecules} = \text{0.2496 mol Cu(OH)}_{2} \times \dfrac{6.022 \times 10^{23}\text{ molecules Cu(OH)}_{2}}{\text{1 mol Cu(OH)}_{2}}\\\\= \mathbf{1.503 \times 10^{23}}\textbf{ molecules Cu(OH)}_{2}\\\text{There are $\large \boxed{\mathbf{1.503 \times 10^{23}}\textbf{ molecules of Cu(OH)}_{2}}$}[/tex]

The number of molecules of copper (II) hydroxide in 23.45 g sample has been [tex]\rm \bold {1.45\;\times\;10^2^3}[/tex].

According to the Avogadro number, the number of molecules in a mole of atom has been equivalent to the Avogadro constant. The value of Avogadro constant has been [tex]\rm 6.023\;\times\;10^2^3[/tex].

The moles of a compound has been given as:

[tex]\rm Moles=\dfrac{Mass}{Molar\;mass}[/tex]

The moles in 23.45 g copper (II) hydroxide has been:

[tex]\rm Moles=\dfrac{23.45}{97.562} \\Moles=0.24\;mol[/tex]

The moles of copper (II) hydroxide has been 0.24 mol.

The number of molecules in 0.24 mol sample has been driven by:

[tex]\rm 1\;mol=6.023\;\times\;10^2^3\;molecules\\0.24\;mol=0.24\;\times\;10^2^3\;molecules\\0.24\;mol=1.45\;\times\;10^2^3\;molecules[/tex]

The number of molecules of copper (II) hydroxide in 23.45 g sample has been [tex]\rm \bold {1.45\;\times\;10^2^3}[/tex].

For more information about molecules in a mole of sample, refer to the link:

https://brainly.com/question/24577356

Answer:1 )T2=134°C   2) T2=339.48°C. 3)

P=817.59 mmHg.

Explanation:

1.Given ;

pressure, P1 of neon gas = 0.646 atm

temperature, T1 =242oC + 273=515oC

Volume, V1 =515ml

Volume V2= 407ml

temperature , T 2= ?

Solution;

And at constant pressure, the volume cools at V2=407 mL at T2=?

From ideal gas equation, PV=nRT

V/T=constant

therefore

V1/V2=T1/T2 = T2=(V2 xT1)/V1

T2=(407 mL x 515 K)/515 mL= 407K.

T2= 407K -273= 134°C.   recall 0°C=273 K)

2..Given ;

pressure, P1 of neon gas = 0.633 atm

temperature, T1 =261oC + 273=534oC

Volume, V1 =694ml

Volume V2= 796ml

temperature , T 2= ?

Solution;

And at constant pressure, the volume expands  at V2=796mL at T2=?

From ideal gas equation, PV=nRT

V/T=constant

therefore

V1/V2=T1/T2 = T2=(V2 xT1)/V1

T2=(796 mL x 534 K)/694mL= 612.48K.

T2= 612.48K -273= 339.48°C. recall 0°C=273 K

3

Given;

moles of CO2= n=0.962 mol,

temperature T=20°C=20+273 K =293 K,

volume V=21.5 L,

gas constant R at L·mmHg/mol·K= 62.3637 L mmHg mol^-1 K^-1

Using  ideal gas equation PV=nRT

P=nRT/V

P=(0.962 mol)x(62.3637mmHg mol^-1 K^-1)x(293 K)/(21.5L)

P=817.59 mmHg.

Answer:

B) The complex ion is favored over solid silver chloride

C) The free Ag+ ion is unstable.

Explanation:

Hello,

In this case, since the dissociation of solid silver chloride occurs at equilibrium with a neglectable solubility product (very small Ksp), which means that the solid tends to remain undissolved:

[tex]AgCl(s)\rightleftharpoons Ag^+(aq)+Cl^-(aq)[/tex]

By the addition of ammonia, the following reaction is favored:

[tex]Ag^+(aq)+2NH_3(aq)\rightleftharpoons [Ag(NH_3)_2]^+(aq)[/tex]

Which has a large equilibrium constant, which means that the formation of the complex is assured. In such a way, by addition of more ammonia, more complex will be formed, therefore B) The complex ion is favored over solid silver chloride is true. Moreover, C) The free Ag+ ion is unstable, since they tend to form the complex once they are formed by the solid silver chloride so it readily reacts.

Best regards.

Answer:

The answer is o2

Explanation:

I took the test

Answer:

This is due to the water moisture present in the recovered sample.

Explanation:

The total amount of material recovered isn’t meant to weigh more than the original sample. However when this happens then it means there is the presence of water moisture in the recovered sample.

The recovered samples however needs to be heated to make it dry and eliminate the water moisture through evaporation.

Answer:

195.5 K

Explanation:

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

2S + 3O2 + 2H2O → 2H2SO4

Next, we shall determine the number of mole in 17.55 g of H2SO4. This can be obtained as follow:

Molar mass of H2SO4 = (2x1) + 32 + (16x4) = 2 + 32 + 64 = 98 g/mol

Mass of H2SO4 = 17.55 g

Mole of H2SO4 =...?

Mole = mass /Molar mass

Mole of H2SO4 = 17.55/98

Mole of H2SO4 = 0.179 mole.

Next, we shall determine the number of mole of O2 needed for the reaction. This can be obtained as illustrated below:

From the balanced equation above,

3 moles of O2 reacted to produce 2 moles of H2SO4.

Therefore, Xmol of O2 will react to produce 0.179 moleof H2SO4 i.e

Xmol of O2 = (3 x 0.179) / 2

Xmol of O2 = 0.2685 mole

Therefore, 0.2685 mole of O2 is needed for the reaction.

Finally, we shall determine the temperature of O2. This can be obtained by using the ideal gas equation as follow:

Volume (V) of O2 = 5.01 L

Pressure (P) = 0.860 atm

Number of mole (n) of O2 = 0.2685 mole

Gas constant (R) = 0.0821 atm.L/Kmol

Temperature (T) =..?

PV =nRT

0.860 x 5.01 = 0.2685 x 0.0821 x T

Divide both side by 0.2685 x 0.0821

T = (0.860 x 5.01) /(0.2685 x 0.0821)

T = 195.5 K

Therefore, the temperature of O2 must be 195.5 K.

Answer:

Answers are in the explanation

Explanation:

It is possible to obtain K of equilibrium of related reactions knowing the laws:

A + B ⇄ C K₁

C ⇄ A + B K = 1 /K₁

The inverse reaction has the inverse K equilibrium

2A + 2B ⇄ 2C K = K₁²

The multiplication of the coefficients of reaction produce a k powered to the number you are multiplying the coefficients

For the reaction:

2 CO2(g) + 4 H2O(g) ⇄ 2 CH3OH(l) + 3 O2(g) K

1) CH3OH(l) + 3/2 O2(g) ⇄ CO2(g) + 2 H2O(g)

This is the inverse reaction but also the coefficients are dividing in the half, that means:

[tex]K_1 = \frac{1}{k^{1/2}} = (1/K)^{1/2}[/tex]

2) CO2(g) + 2 H2O(g) ⇄ CH3OH(l) + 3/2 O2(g)

Here,the only change is the coefficients are the half of the original reaction:

[tex]K_2 = K^{1/2}[/tex]

3) 2CH3OH(l) + 3 O2(g) ⇄ 2 CO2(g) + 4 H2O(g)

This is the inverse reaction. Thus, you have the inverse K of equilibrium:

[tex]K_3 = \frac{1}{K}[/tex]

Answer:

AgBr

Explanation:

Silver bromide has a very low solubility product constant of about 7.7 ×10^-13 in pure water hence it is not quite soluble in pure water.

However, with NaCN, the AgBr forms the complex [Ag(CN)2]^2- which has a formation constant of about 5.6 ×10^8. This very high formation constant implies that the complex is easily formed leading to the dissolution of AgBr in NaCN.

The equation for the dissolution of AgBr in cyanide is shown below;

AgBr(s) + 2CN^-(aq) ----> [Ag(CN)2]^2-(aq) + Br^-(aq)

Answer:

Cells are the basic structures of all living organisms. Cells provide structure for the body, take in nutrients from food and carry out important functions. ... These organelles carry out tasks such as making proteins?, processing chemicals and generating energy for the cell

Answer: I absolutely love this question! Biology is so interesting, so I always love to answer the curiosity of others regarding biology, such as that!

Cells are simply the basic structures of all organisms, that are living, of course! Cells provide structure for the body, and they also take in nutrients that your body needs from food and they carry out important functions. These organelles carry out tasks such as making proteins, processing chemicals, and generating energy for the cell. Isn’t that cool?

Hope this helped! <3

Answer:

In order from lowest to highest:

Methane < Ethane < Chloroethene < Methanol

i.e: CH4 < CH3CH3 < CH3CH2OH < CH3CH2Cl

Explanation:

Compounds with stronger molecular fore have higher boiling points, thus making the molecules more difficult to pull apart. The presence of chains also increases the molecular dispersion. The dipole force of ethanol makes it have a very high boiling point.

I'm positive this explanation would suffice. Best of luck.

The order of increasing boiling points of the substances listed is; CH4 < CH3CH3 < CH3CH2Cl < CH3CH2OH.

Intermolecular interactions occur between molecules. The boiling point and melting points of substances depends on the nature and magnitude of intermolecular interaction between the molecules of the substance.

The order of increasing boiling points of the substances listed is as follows; CH4 < CH3CH3 < CH3CH2Cl < CH3CH2OH. CH3CH2OH has the highest boiling point due to intermolecular hydrogen bonds in the molecule. Though CH4 and CH3CH3 are both alkanes, CH3CH3 has a higher molecular mass and consequently greater dispersion forces and a higher boiling point.

Learn more: https://brainly.com/question/865531

Answer:

(D) The reaction cannot take place in a single elementary step

Explanation:

Statements are:

(A) The time it takes for [CH3I] to decrease to 0.005 M is independent of [N3-], as long as [N3] >> [CH3I].

B) If the initial concentrations of azide and CH3I are equal, then it takes half as long for [CH3I] to decrease to 0.005 M as it does for it to decrease from 0.005 M to 0.0025 M.

(C) The reaction rate is significantly smaller if excess I- is added to the solution.

(D) The reaction cannot take place in a single elementary step.

The rate of the reaction is:

rate = k[CH3I][N3–].

That means rate depends of concentration of CH₃I as much as N₃⁻ concentration

(A) The time it takes for [CH3I] to decrease to 0.005 M is independent of [N3-], as long as [N3] >> [CH3I]. FALSE. The reaction rate depends of N₃⁻ as much as CH₃I

B) If the initial concentrations of azide and CH3I are equal, then it takes half as long for [CH3I] to decrease to 0.005 M as it does for it to decrease from 0.005 M to 0.0025 M. FALSE. Reaction is second-order. Half-life is 1/K[A]₀. If initial concentration is 0.1M, to a concentration of 0.005M it takes:

1/K*0.1. If initial concentration is 0.005M it takes 1/K*0.005. That means it takes half to decrease from 0.005M to 0.0025 as it does for it to decrease from 0.01M to 0.005M.

(C) The reaction rate is significantly smaller if excess I- is added to the solution. FALSE. Reaction rate is independent of I⁻

(D) The reaction cannot take place in a single elementary step. TRUE. As this reaction is a single-replacement reaction implies the formation  of 1 C-N bond. But also the rupture of the C-I bond is impossible to explain this kind of reaction in a single elementary step.

Answer:

d. carboxyl

Explanation:

The presence of carbonyl group (>C=O)) and a hydroxyl group ( (−OH) on the same carbon atom is called a "carboxyl" group. A carboxyl group is represented as COOH and acts as the functional group part of carboxylic acids.

For example:

Hence, the correct option is "d. carboxyl ".

Answer:

Empirical formulae is NO2

Molecular Formulae is NO2

Answer:

The equilibrium concentration of ICl is 2.26 M

Explanation:

Chemical equilibrium is a state in which no changes are observed as time passes, despite the fact that the substances present continue to react. This is because chemical equilibrium is established when the forward and reverse reaction take place simultaneously at the same rate.

For the study of chemical equilibrium, the so-called equilibrium constant Kc is useful. Being:

aA + bB ⇔ cC + dD

the equilibrium constant Kc is:

[tex]Kc=\frac{[C]^{c} *[D]^{d} }{[A]^{a}*[B]^{b} }[/tex]

That is, the constant Kc is equal to the multiplication of the concentrations of the products raised to their stoichiometric coefficients by the multiplication of the concentrations of the reactants also raised to their stoichiometric coefficients.

For the reaction:

2 ICl (g) ⇌ I₂ (g) +Cl₂ (g)

the constant Kc is:

[tex]Kc=\frac{[I_{2} ]*[Cl_{2} ]}{[ICl]^{2} }[/tex]

Being Kc =0.110 and the concentration being the amount of moles of solute that appear dissolved in each liter of the mixture and being calculated by dividing the moles of the solute by the liters of the solution:

and replacing in the constant we get:

[tex]0.110=\frac{0.750*0.750}{[ICl]^{2} }[/tex]

Solving, you get the ICl concentration at equilibrium:

[tex][ICl]^{2} =\frac{0.750*0.750}{0.110 }[/tex]

[tex][ICl] =\sqrt{\frac{0.750*0.750}{0.110 }}[/tex]

[ICl]= 2.26 M

The equilibrium concentration of ICl is 2.26 M