How to prepared sodium chloride solution in the laboratory.​

2.96 × 10²³ molecules is required if Alex drips hydrochloric acid onto a 5.9 g piece of magnesium in a single displacement reaction

According to this question, hydrochloric acid (HCl) reacts with magnesium metal (Mg) to produce magnesium chloride and hydrogen has as follows:

2HCl(aq) + Mg(s) → MgCl2(aq) + H2(g)

Where; Mg = 24g/mol

mole = 5.9/24

mole = 0.246mol of Mg

To convert mole to number of molecules, we multiply number of moles by 6.02 × 10²³ (Avogadro's no.)

Hence, number of molecules of HCl required is 0.492mol × 6.02 × 10²³

= 2.96 × 10²³ molecules of HClHCl

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Answer:

pH of the buffer is 3.75

Explanation:

It is possible to find pH of a buffer using Hendersson-Hasselbalch equation:

pH = pKa + log [A⁻] / [HA]

Where [A⁻] is molar concentration of the conjugate base and [HA] concentration of the weak acid

In the lactic buffer, pKa = 3.86. Lactic acid is the weak acid and its conjugate base is tha lactate salt. H-H equation for this buffer is:

pH = 3.86 + log [Lactate] / [Lactic acid]

Replacing with the concentrations of the problem:

pH = 3.86 + log [0.10M] / [0.13M]

pH = 3.75

Answer:

222.3 ml of a 0.130 M aqueous solution of chromium (II) nitrate must be taken to obtain 5.08 grams of the salt.

Explanation:

Being:

the molar mass of chromium (II) nitrate, Cr(NO₃)₂ is:

Cr(NO₃)₂ = 52 g/mole + 2* (14 g/mole + 3* 16 g/mole)= 176 g/mole

So: if 176 grams are present in 1 mole of the compound, 5.08 grams in how many moles of the compound will be present?

[tex]amount of moles=\frac{5.08 grams* 1 mole}{176 grams}[/tex]

amount of moles=0.0289 moles

Molarity (M) is the number of moles of solute that are dissolved in a given volume. It is then calculated by dividing the moles of the solute by the volume of the solution:

[tex]molarity (M)=\frac{number of moles of solute}{volume}[/tex]

Molarity is expressed in [tex]\frac{moles}{liter}[/tex]

So in this case:

Replacing:

[tex]0.130 M=0.130 \frac{moles}{liter} =\frac{0.0289 moles}{volume}[/tex]

Solving:

[tex]volume=\frac{0.0289 moles}{0.130 \frac{moles}{liter} }[/tex]

volume=0.2223 liters

Being 1 L= 1,000 mL:

volume=0.222 liters= 222.3 mL

222.3 ml of a 0.130 M aqueous solution of chromium (II) nitrate must be taken to obtain 5.08 grams of the salt.

Answer:

156 g Br. Explanation: In order to figure out how many grams of bromine you get in that many grams of calcium bromide, CaBr2 , you must find ...

Answer:

156 g

Explanation:156 g

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The words given are not clear, so the clear question is as follows:

Match the words below to the appropriate blanks in the sentences. Make certain each sentence is complete before submitting your answer:

A. β-1,4- and α-1,6-glycosidic

B. α-1,4-glycosidic

C. α-1,4-galactose

D. an unbranched glucose

E. a branched fructose

F. α-1,6-glycosidic

Amylose is ......... polymer of ....... units joined by ........ bonds.

Amylopectin is ....... polymer of .......units joined by ........ bonds.

Answer:

D. an unbranched glucose

C. α-1,4-galactose

B. α-1,4-glycosidic

E. a branched fructose

A. β-1,4- and α-1,6-glycosidic

F. α-1,6-glycosidic

Explanation:

Amylose and amylopectin are two types of polysaccharides that can be found in starch granules.

Amylose is linear or unbranched glucose polymer of α-1,4-galactose units that are joined by α-1,4-glycosidic.

Amylopectin is a branched fructose polymer of β-1,4- and α-1,6-glycosidic units joined by α-1,6-glycosidic bonds.

Hence, the correct answers in the sequential order are:

Amylose:

D. an unbranched glucose

C. α-1,4-galactose

B. α-1,4-glycosidic

Amylopectin:

E. a branched fructose

A. β-1,4- and α-1,6-glycosidic

F. α-1,6-glycosidic

Answer:

ΔG°  = 1022. 8 kJ

Explanation:

ΔH° = –199 kJ/mol

ΔS° = –4.1 J/K·mol

T = 25°C = 25 + 273 = 298K (Converting to kelvin temperature)

ΔG° = ?

The relationship between these varriables are;

ΔG° = ΔH°  - TΔS°

ΔG° = –199 - 298 (–4.1)

ΔG° = -199 + 1221.8

ΔG°  = 1022. 8 kJ

To calculate ΔG, the following equation should be used:

ΔG° = ΔH°  - TΔS°

Given:

ΔH° = –199 kJ/mol,  

ΔS° = –4.1 J/K·mol

T=25+273K=298K  

Substitute the respective values:

ΔG° = ΔH°  - TΔS°

       =–199 kJ/mol-(298K×(-4.1 J/K·mol*(1KJ/1000J)))

       =-197.78kJ/mol

Thus, we can conclude the value of ΔG°=-197.78kJ/mol  

Learn more about ΔG° here:

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Answer:

Explanation:

The steps to calculate the Zeff is :

1)  Write  the electronic configuration.

Carbon: 1s2 2s2 2p2

Oxygen: 1s2 2s2 2p4

2) there are two core electrons in each atom and four in carbon and six in oxygen.

1s) (2s2p)

3) as mentioned the shielding of electrons within the same shell is negligible.

4) for electron of s or p orbital  the shielding contribution by the electrons having a principal quantum number less by one would be 0.85 each. And all electrons further left would contribute an amount of 1.0 each.

5) For oxygen:

Zeff = Z - S

S = 2X0.85 = 1.7

Zeff = 8- 1.7 = 6.3

For carbon

Zeff = Z - S

S = 2X0.85 = 1.7

Zeff = 6- 1.7 = 4.3

Answer:

The oxidation state of silver in [tex]\rm Ag_2O[/tex] is [tex]+1[/tex].

The oxidation state of sulfur in [tex]\rm SO_2[/tex] is [tex]+4[/tex].

Explanation:

The oxidation states of atoms in a compound should add up to zero.

There are two silver [tex]\rm Ag[/tex] atoms and one oxygen [tex]\rm O[/tex] atom in one formula unit of [tex]\rm Ag_2O[/tex]. Therefore:

[tex]\begin{aligned}&\rm 2 \times \text{Oxidation state of $\rm Ag$}+ \rm 1 \times \text{Oxidation state of $\rm O$} = 0\end{aligned}[/tex].

The oxidation state of oxygen in most compounds (with the exception of peroxides and fluorides) is [tex]-2[/tex]. Silver oxide [tex]\rm Ag_2O[/tex] isn't an exception. Therefore:

[tex]\begin{aligned}&\rm 2 \times \text{Oxidation state of $\rm Ag$}+ \rm 1 \times \text{Oxidation state of $\rm O$} = 0\\ &\rm 2 \times \text{Oxidation state of $\rm Ag$}+ \rm 1 \times (-2) = 0\end{aligned}[/tex].

Solve this equation for the (average) oxidation state of [tex]\rm Ag[/tex]:

[tex]\text{Oxidation state of $\rm Ag$} = 1[/tex].

Similarly, because there are one sulfur [tex]\rm S[/tex] atom and two oxygen [tex]\rm O[/tex] atoms in each [tex]\rm SO_2[/tex] molecules:

[tex]\begin{aligned}&\rm 1\times \text{Oxidation state of $\rm S$}+ \rm 2 \times \text{Oxidation state of $\rm O$} = 0\end{aligned}[/tex].

The oxidation state of [tex]\rm O[/tex] in [tex]\rm SO_2[/tex] is also [tex]-2[/tex], not an exception, either.

Therefore:

[tex]\begin{aligned}&\rm 1 \times \text{Oxidation state of $\rm S$}+ \rm 2 \times \text{Oxidation state of $\rm O$} = 0\\ &\rm 1 \times \text{Oxidation state of $\rm S$}+ \rm 2 \times (-2) = 0\end{aligned}[/tex].

Solve this equation for the oxidation state of [tex]\rm S[/tex] here:

[tex]\text{Oxidation state of $\rm S$} = 4[/tex].

Answer:

I hope it works

Explanation:

As we know that

w=m*g

given m=0.145 , g=9.8

hence we get

w= (9.8)*(0.145)

w=1.421 m/sec 2

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Answer:

[tex]Speed = 3.30 \frac{km}{hr}[/tex]

Explanation:

Given

Distance = 1 mile

Time = 8.92 minutes

Required

Calculate Speed in km/hr

Speed is calculated as thus;

[tex]Speed = \frac{Distance}{Time}[/tex]

Substitute 1 mile for distance and 8.92 minutes for time

[tex]Speed = \frac{1\ mile}{8.92\ minutes}[/tex]

Convert Miles to Kilometres

If

[tex]1\ mile = 1609\ m[/tex];

Then

[tex]1\ mile = \frac{1609\ km}{1000}[/tex]

[tex]1\ mile = 1.609\ km[/tex] --- (1)

Convert minutes to hour

[tex]1\ minutes = 0.0167\ hour[/tex]

Multiply both sides by 8.92

[tex]8.92 * 1\ minutes = 0.0167\ hour * 8.92[/tex]

[tex]8.92 \ minutes = 0.148964\ hour[/tex] ---- (2)

By substituting (1) and (2) in [tex]Speed = \frac{1\ mile}{8.92\ minutes}[/tex], we have

[tex]Speed = \frac{1.609\ km}{0.48694\ hour}[/tex]

[tex]Speed = 3.304309 \frac{km}{hr}[/tex]

[tex]Speed = 3.30 \frac{km}{hr}[/tex] -- Approximated

Answer:

1 ethanol is right answer

Explanation:

CH3- CH2-OH

Answer:

4.84g of FeO is the theoretical yield

Explanation:

The Iron, Fe(s), reacts with oxygen, O₂(g), producing Iron (II) oxide, as follows:

2Fe(s) + O₂(g) → 2FeO

Theoretical yield is the yield of a reaction in which you assume the 100% of reactants is converted in products.

To find theoretical yield we need to find moles of Iron, and, knowing 2 moles of Fe produce 2 moles of FeO (Ratio 1:1), we can find theoretical yield of FeO as follows:

Moles Fe (Molar mass: 55.845g/mol)

Using the molar mass of the compound we can convert grams to moles, thus:

3.76g Fe × (1mol / 55.845g) = 0.0673 moles of Fe

Moles and mass of FeO

As there are in reaction 0.0673 moles Fe, assuming a theoretical yield (And as ratio of the reaction is 1:1), you will obtain 0.0673 moles of FeO.

Theoretical yield is given in grams, As molar mass of FeO is 71.844g/mol, theoretical yield of the reaction is:

0.0673 moles FeO × (71.844g / mol) =

Answer:

The sun

Explanation:

The sun is the primary source of energy in most living communities. The producers or the green plants that prepare their own food by the use of sunlight and other natural resources. Carbon dioxide, water, and other minerals are used by the plants to make their food in the presence of chlorophyll. Plants are then consumed by the consumers. This chain helps in forming the food chain and the food web.

Answer:

D) 152 g

Explanation:

a mass of 1 mol Cr2O3 = 2 × 52 + 3 × 16 = 152 g number of moles of Cr2O3.

Answer:

ch3:-methanide

No2:-nitrogen dioxide

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Answer:

A    ⇒ 20

B    ⇒ 40

C    ⇒ Ca

D    ⇒ 10

E     ⇒ 9

F     ⇒ F

Explanation:

edge 2021

Answer:

the person above is correct

Explanation:

Answer:

Spacecraft’s acceleration (a) = 0.10 N / 500 kg

Explanation:

Given:

Mass of Spacecraft (M) = 500 Kg

Force generate by engine (F) = 0.10 N

Find:

Spacecraft’s acceleration (a)

Computation:

F = Ma

0.10 = 500 (a)

a = 0.10 / 500

Spacecraft’s acceleration (a) = 0.10 N / 500 kg

The expression which can be used to find the spacecraft’s acceleration if its engine created a net force of 0.10 N is  0.10 N/500Kg.

We know that force is the product of the mass a body and its acceleration. The result of motion is the action of an unbalanced force. We have the following information;

Mass of the spacecraft = 500 kg

Force on the engine =  0.10 N

From Newton's law;

F = ma

F = force

m = mass

a = acceleration

a = F/m

acceleration = 0.10 N/500Kg

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Explanation:

Physical change

★ Boiling of water

❤︎ freezing of water

❣︎ washing of clothes

♫︎ mixing black and brown stones

Chemical change

➪ making of dough

㋛︎ burning of wood

❥︎ cooking of the raw food

❁ burning of paper

ꨄ︎ rusting of iron

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Answer:

(i). C6H2COOH and Na2CO3(aq)

observation: Bubbles of a colourless gas (carbon dioxide gas)

(ii) CH3CH2CH2OH and KMnO4 /H

observation: The orange solution turns green.

[This is because oxidation of propanol to propanoic acid occurs]

(iii) CH3CH2OH and CH3COOH + conc. H2SO4

observation: A sweet fruity smell is formed.

[This is because an ester, diethylether is formed]

(iv) CH3CH = CHCH3 and Br2 /H2O

observation: a brown solution is formed.

Explanation:

Hey there!

Charles law states that the volume of gas is directly proportional to the absolute temperature at constant pressure.

As the fact is, at a constant pressure the volume of fix amount of dry gas is directly proportional to absolute temperature from Charles law.

Since V and T are directly varying directly, we can write the equation using constant "k".

V/T = k

In this case the value of k depends on the pressure of gas, the amount of gas and also unit volume.

V/T = k .........(i)

Let us consider V1 and T1 the Volume and temperature of the ideal gases.

Then the equation is;

V1/T1 =k........(ii)

After this let change the temperature and volume be T2 and V2, respectively.

Then the equation is:

V2/T2 = k.......(iii)

Now; Equating equation (ii) and (iii)…

V1/T1 = V2/T2

So, this the formula. (i.e V1/T1 = V2/T2).

Hope it helps!

Answer:

yes it is corrwect iyt is absolitle correct

Explanation:

Answer:

315 g

Explanation:

Step 1: Write the thermochemical equation

2 H₂O(l) → 2 H₂(g) + O₂(g)      ΔH = +572 kJ

Step 2: Calculate the molar of water decomposed by 5.00 × 10³ kJ of energy

According to the thermochemical equation, 572 kJ are required to decompose 2 moles of water.

5.00 × 10³ kJ × (2 mol/572 kJ) = 17.5 mol

Step 3: Calculate the mass corresponding to 17.5 moles of water

The molar mass of water is 18.02 g/mol.

17.5 mol × 18.02 g/mol = 315 g

Answer:

-2, -2 and 0.

- Respiration is a process in which energy is produced and photosynthesis is a process in which energy is used.

Explanation:

Hello,

In this case, oxygen is a substance that is used for animals and us to acquire the energy necessary for several functions by the cellular respiration (we also need glucose), besides, it is a product of the photosynthesis carried out by vegetable cells (plants). Moreover, carbon dioxide and water are used by the plants to produce oxygen we need as well as glucose via the aforementioned photosynthesis, thus, both chemical reactions are shown below:

[tex]C_6H_{12}O_6+6O_2\rightarrow 6CO_2+6H_2O\ \ \ respiration\\\\6CO_2+6H_2O\rightarrow C_6H_{12}O_6+6O_2\ \ \ photosynthesis[/tex]

In such a way, since the oxygen in carbon dioxide and water has an oxidation state of -2 (reduced form) we can say that the respiration is a process in which energy is produced and since the oxygen yielded during the photosynthesis has an oxydation state of 0, we can say that photosynthesis is a process in which energy is used.

Best regards.

Answer:

It has denatured

Explanation:

When the temperature get high the enzymes tend to change shape and denaturing occurs.

Answer:

[tex]pH=11.12[/tex]

Explanation:

Hello,

In this case, ammonia dissociation is:

[tex]NH_3(aq)+H_2O(l)\rightleftharpoons NH_4^+(aq)+OH^-(aq)[/tex]

So the equilibrium expression:

[tex]Kb=\frac{[NH_4^+][OH^-]}{[NH_3]}[/tex]

That in terms of the reaction extent and the initial concentration of ammonia is written as:

[tex]1.8x10^{-5}=\frac{x*x}{0.10M-x}[/tex]

Thus, solving by using solver or quadratic equation we find:

[tex]x=0.00133M[/tex]

Which actually equals the concentration of hydroxyl ion, therefore the pOH is computed:

[tex]pOH=-log([OH^-])=-log(0.00133)=2.88[/tex]

And the pH from the pOH is:

[tex]pH=14-pOH=14-2.88\\\\pH=11.12[/tex]

Best regards.

Answer:

The length the divider is to  equilibrium from Part A = 1.30 m and from Part B = 3.70 m

Explanation:

Given that:

A rectangular cube with 3.2 m breadth, 1.2 m height and 5 m in length is splitted into two parts.

The diagrammatic expression for the above statement can be found in the attached diagram below.

The container has a movable airtight divider that divides its length as necessary.

Part A has 58 moles of gas

Part B has 165 moles of a gas.

Thus, the movable airtight divider will stop at a length where the pressure on it is equal on both sides.

i.e

[tex]\mathtt{P = P_A = P_B}[/tex]

Using the ideal gas equation,

PV = nRT

where, P,R,and  T are constant.

Then :

[tex]\mathsf{\dfrac{V_A}{n_A}= \dfrac{V_B}{n_B}}[/tex]

[tex]\mathsf{\dfrac{L_A \times B \times H}{n_A}= \dfrac{L_B \times B \times H}{n_B}}[/tex] --- (1)

since Volume of a cube = L × B × H

From the question; the L = 5m

i,e

[tex]\mathsf{L_A +L_B}[/tex] = 5

[tex]\mathsf{L_A = 5 - L_B}[/tex]

From equation (1) , we divide both sides by (B × H)

Then :

[tex]\mathsf{\dfrac{L_A }{n_A}= \dfrac{L_B }{n_B}}[/tex]

[tex]\mathsf{\dfrac{5-L_B}{58}= \dfrac{L_B }{165}}[/tex]

By cross multiplying; we have:

165 ( 5 - [tex]\mathsf{L_B}[/tex] )  = 58 (

825 - 165[tex]\mathsf{L_B}[/tex]  = 58

825 = 165[tex]\mathsf{L_B}[/tex] +58

825 = 223[tex]\mathsf{L_B}[/tex]

[tex]\mathsf{L_B}[/tex] = 825/223

[tex]\mathsf{L_B}[/tex]  = 3.70 m

[tex]\mathsf{L_A = 5 - L_B}[/tex]

[tex]\mathsf{L_A = 5 - 3.70}[/tex]

[tex]\mathsf{ L_A}[/tex] = 1.30 m

The length the divider is to  equilibrium from Part A = 1.30 m and from Part B = 3.70 m

Answer:

2

Explanation:

A single covalent bond is formed when two electrons are shared between the same two atoms, one electron from each atom.

Answer:

the answer is 2

Explanation:

Answer:

(a) Chromatography

(b) DNA fingerprinting

(c) Origin

(d) Sweet C consists of more colours than sweet D.

  ii. The speed of colours in sweet C are proportional to one another, while that of colours in D is not.

Explanation:

Chromatography is one of the physical method of separating mixtures. This process composed of the ability of the constituents in a mixture to separate by virtue of rate of movement through a medium, thus separates into constituents.

It can be used to determine the soluble constituents of a given mixture. And for purification purpose.