Calculate experimental error using the following data: the measured value equals 1.4 cm; the accepted value equals 1.2 cm.
a) -14.3%
b) 4.3%
c) -16.7%
d) 16.7%

Answer:

4.3

Explanation:

Data provided in the question as per the question is as follows

[tex]k_b = 1.6 \times 10^{-6}[/tex]

Now we use the log in both the sides

So,

[tex]Pk_b = -log\ k_b = -log (1.6 \times 10^{-6})[/tex]

[tex]Pk_b[/tex] = 5.795

And, C = 0.0015

log c = -2.823

Now pH is

[tex]= \frac{1}{2} (Pk_b - log\ c)[/tex]

[tex]= \frac{1}{2} (5.795 - (-2.823))[/tex]

= 4.3

Hence, the pH of the solution of 0.0015 M morphine is 4.3 and the same is to be considered by applying the above formulas and the calculations part

Answer:

The answer is option a. The evaporation of water from the skin

Explanation:

An endothermic reaction is any synthetic reaction that retains heat from its environment. The ingested energy gives the enactment energy to the reaction to happen.

No new bonds formed, no bonds broken in this example. water molecules go from liquid to vapour (gas ), intermolecular bond exist between polar (-OH) molecules and energy is required to break these bonds during the change from liquid to gas. So, it is endothermic .

Remaining three above examples are exothermic. combustion of gas releases energy(exothermic). burninig of the candle exothermic because the energy released from the oxygen into carbon dioxide and water.oxidation of iron also exothermic

Answer:

#1: 0.00144 mmolHCl/mg Sample

#2: 0.00155 mmolHCl/mg Sample

#3: 0.00153 mmolHCl/mg Sample

Explanation:

A antiacid (weak base) will react with the HCl thus:

Antiacid + HCl → Water + Salt.

In the titration of antiacid, the strong acid (HCl)  is added in excess, and you're titrating with NaOH moles of HCl that doesn't react.

Moles that react are the difference between mmoles of HCl - mmoles NaOH added (mmoles are Molarity×mL added). Thus:

Trial 1: 0.391M×14.00mL - 0.0962M×34.26mL = 2.178 mmoles HCl

Trial 2: 0.391M×14.00mL - 0.0962M×33.48mL = 2.253 mmoles HCl

Trial 3: 0.391M×14.00mL - 0.0962M×33.84mL = 2.219 mmoles HCl

The mass of tablet in mg in the 3 experiments is 1515mg, 1452mg and 1443mg.

Thus, mmoles HCl /mg OF SAMPLE for each trial is:

#1: 2.178mmol / 1515mg

#2: 2.253mmol / 1452mg

#3: 2.219mmol / 1443mg

Answer:

A.  1.88 mol H₂

B.  182 g Al₂(SO₄)₃

C.  54.8%

Explanation:

2 Al  +  3 H₂SO₄  ⇒  Al₂(SO₄)₃  +  3 H₂

A.  Convert grams of Al to moles.  The molar mass is 26.98 g/mol.

(33.8 g)/(26.98 g/mol) = 1.253 mol Al

Use stoichiometry to convert moles of Al to moles of H₂.  Looking at the equation, you can see that for every 2 mol of Al consumed, 3 moles of H₂ is produced.  Use this relationship.

(1.253 mol Al) × (3 mol H₂)/(2 mol Al) = 1.879 mol H₂

You will produce 1.88 mol of H₂ gas.

B.  Again, use stoichiometry.  For every 3 moles of H₂SO₄ consumed, 1 mole of Al₂(SO₄)₃ is produced.

(1.60 mol H₂SO₄) × (1 mol Al₂(SO₄)₃/3 mol H₂SO₄) = 0.533 mol Al₂(SO₄)₃

Convert moles of Al₂(SO₄)₃ to grams.  The molar mass is 342.15 g/mol.

(0.533 mol) × (342.15 g/mol) = 182.48 g Al₂(SO₄)₃

You will produce 182 g of Al₂(SO₄)₃.

C.  Calculate percent yield by dividing the actual yield by the theoretical yield.  Multiply by 100%.

(100.0/182.48) × 100% = 54.8%

The percent yield is 54.8%.

Answer:

The enthalpy change is −636.9798 kJ

Explanation:

The equation of the reaction between Carbon and Oxygen can be represented as :

[tex]C_{(s)} + O_{2(g)} \to CO_{2_(g)} \ \ \ \ \ \ \Delta H = -394 \ \ kJ/mol[/tex]

molar mass of Carbon = 12 mole

when mass of  19.399999999999999 g of carbon reacted with oxygen;

the number of moles = mass/molar mass

the number of moles = 19.399999999999999/12

the number of moles = 1.6167 mol

Thus the enthalpy change when  1 mole of carbon react with oxygen = -394 kJ/mol

Therefore when 1.6167 moles react with oxygen; we have:

= 1.6167 mol ×  -394 kJ/mol

= −636.9798 kJ

Answer:

Alcl3 and Cl2

Explanation:

the product above will be formed

Answer:

silver (Ag) and aluminum chloride (AlCl₃)

Explanation:

The reaction between aluminum and silver chloride is a single replacement reaction. A single replacement reaction is when one element switches places with another.

Al + 3AgCl ➔︎ 3Ag + AlCl₃

In the reaction, the cations (positively charged ions) switch places. Aluminum (Al) switches places with Silver (Ag). So, the products of the reaction are silver and aluminum chloride.

Hope this helps.

Answer:

1. It dissolves much more ice faster than sodium chloride

2. Calcium chloride is more effective in melting ice at lower temperatures.

Explanation:

Salts are used to melt ice on roadways and sidewalks because they help to lower the freezing point of water.

Sodium chloride and calcium chloride are both salts used for this purpose but calcium chloride is usually preferred for the following two reasons:

1. It dissolves much more ice faster than sodium chloride: Calcium chloride dissolves much more ice faster than sodium chloride because when it dissociates, it produces three ions instead of the two produced when sodium chloride. Therefore, the heat of hydration of its ions is greater than that of sodium chloride.

2. Calcium chloride is more effective in melting ice at lower temperatures. It lowers the freezing point of water more than sodium chloride. Calcium chloride is able to lower the freezing point of water to about -52°C while sodium chloride only lowers it to about -6°C.

Answer:

2.28 M

Explanation:

Step 1: Given data

Percent by mass (%m/m): 20.0 %

Density (ρ): 1.114 g/mL

Step 2: Calculate the percent by volume (%m/v)

We will use the following expression.

[tex]\% m/v = \% m/m \times \rho = 20.0 \% \times 1.114g/mL = 22.3 g \% mL[/tex]

Step 3: Calculate the moles of solute in 100 mL of solution

The molar mass of phosphoric acid is 97.99 g/mol. The moles corresponding to 22.3 g are:

[tex]22.3g \times \frac{1mol}{97.99g} = 0.228mol[/tex]

Step 4: Calculate the molarity of the solution

0.228 moles of solute are in 100 mL (0.100 L) of solution. The molarity of the solution is:

[tex]M = \frac{0.228mol}{0.100L} =2.28 M[/tex]

Answer:

0.76 M

30 g/L

Explanation:

Step 1: Given data

Step 2: Calculate the molarity of the base

We will use the following expression.

[tex]Ma \times Va = Mb \times Vb\\Mb = \frac{Ma \times Va}{Vb} = \frac{0.175M \times 375mL}{86mL} = 0.76 M[/tex]

Step 3: Calculate the concentration of the base in g/L

The molar mass of NaOH is 40.00 g/mol.

[tex]\frac{0.76mol}{L} \times \frac{40.00g}{mol} = 30 g/L[/tex]

Answer:

See explanation.

Explanation:

Hello,

In this case, for the described chemical reaction:

2 HCl(aq) + Mg(OH)2(aq) → MgCl2(aq) + 2 H2O(l)

We can notice there is a 2:1 molar ratio between the moles of hydrochloric acid and magnesium hydroxide, therefore, at the equivalence point:

[tex]n_{HCl}=2*n_{Mg(OH)_2}[/tex]

And in terms of volumes and concentrations we verify:

[tex]V_{HCl}M_{HCl}=2*V_{Mg(OH)_2}M_{Mg(OH)_2}[/tex]

So we use the given data to proof it:

[tex]4.3mL*0.417M=2*11.9mL*0.151M\\1.793=3.594[/tex]

Therefore, we can conclude the data is wrong by means of the 2:1 mole ratio that for sure was not taken into account. This is also supported by the fact that normalities are actually the same, but the nomality of magnesium hydroxide is the half of the hydrochloric acid normality since the acid is monoprotic and the base has two hydroxyl ions.

Best regards.

Answer:

A. Partial pressure of krypton, Kr is 346.97 mmHg

B. Partial pressure of nitrogen, N2 is 364.03 mmHg.

Explanation:

Step 1:

Data obtained from the question. This include the following:

Total pressure (Pt) = 711 mmHg

Mass of Kr = 11.7 g

Mass of N2 = 4.10 g

Partial pressure of Kr =..?

Partial pressure of N2 =...?

Step 2:

Determination of the number of mole of krypton, Kr and nitrogen, N2. This is illustrated below:

Molar mass of Kr = 84g/mol

Mass of Kr = 11.7g

Mole of Kr =?

Mole = mass /Molar mass

Mole of Kr = 11.7/84 = 0.139 mole

Molar mass of N2 = 2x14 = 28g/mol

Mass of N2 = 4.10g

Mole of N2 =?

Mole = mass /Molar mass

Mole of N2 = 4.1/28 = 0.146 mole

Step 3:

Determination of the mole fraction for each gas. This is illustrated below:

Mole of Kr = 0.139 mole

Mole of N2 = 0.146 mole

Total mole = 0.139 + 0.146 = 0.285 mole

Mole fraction of Kr = mol of Kr/total mol

Mole fraction of Kr = 0.139/0.285

Mole fraction of Kr = 0.488

Mole fraction of N2 = mol of N2/total mol

Mole fraction of N2 = 0.146/0.285

Mole fraction of N2 = 0.512

A. Determination of the partial pressure of krypton, Kr.

This is illustrated below:

Total pressure (Pt) = 711 mmHg

Mole fraction of Kr = 0.488

Partial pressure of Kr =..?

Partial pressure = mole fraction x total pressure

Partial pressure of Kr = 0.488 x 711

Partial pressure of Kr = 346.97 mmHg

B. Determination of the partial pressure of nitrogen, N2

This is illustrated below:

Total pressure (Pt) = 711 mmHg

Mole fraction of N2 = 0.512

Partial pressure of N2 =?

Partial pressure = mole fraction x total pressure

Partial pressure of N2 = 0.512 x 711

Partial pressure of N2 = 364.03 mmHg

Answer:

23.36mL of the stock solution are required.

Explanation:

A dilution consist in the addition of solvent to decreases the concentration of a stock solution (The solution more concentrated).

As you want to prepare 250.0mL = 0.2500L of a 0.1342M NaOH, moles of NaOH you require to make this concentration in this volume are:

0.2500L × (0.1342mol / L) = 0.03355 moles of NaOH you require in the diluted solution.

These moles comes from the 1.436M stock solution. The volume of the stock solution you need to add is:

0.03355moles NaOH × (1L / 1.436mol) = 0.02336L of the 1.436M solution =

Answer:

2.75X10^16

Explanation:

C=FXwavelength

wavelength=C/F

We have that for the Question "Calculate the wavelength in meters of electromagnetic radiation that has a frequency of 1.09 × 10⁸ s⁻¹."

it can be said that  the wavelength in meters of electromagnetic radiation that has a frequency of 1.09 × 10⁸ s⁻¹ is

[tex]\lambda=2.7522m[/tex]

From the question we are told

Calculate the wavelength in meters of electromagnetic radiation that has a frequency of 1.09 × 10⁸ s⁻¹. (c = 3.00 X 10⁸ m/s)

Generally the equation for the Wavelength  is mathematically given as

[tex]\lambda=\frac{c}{f}\\\\Therefore\\\\\lambda=\frac{c}{f}\\\\\lambda=\frac{3*10^8}{1.09*10^8}\\\\[/tex]

[tex]\lambda=2.7522m[/tex]

Therefore

the wavelength in meters of electromagnetic radiation that has a frequency of 1.09 × 10⁸ s⁻¹ is

[tex]\lambda=2.7522m[/tex]

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Answer:

C. the evolution of building techniques

Hope this helps.

Answer:

3.74 atmospheres

Explanation:

If the temperature is constant, then the formula is

V*P = V1 * P1

V = 22.6 L

P = 1.67 atm

V1 = 10.0 L

P1 = ??

=============

22.6 * 1.67 = 10 * P1

37.742 = 10 * P1

37.742/10 = P1

P1 = 3.742

Note there are 3 sig digs in each given, so the answer should be

P1 = 3.74 atmospheres

Answer:

THE MASS OF 7.68 *10^24 MOLECULES OF PHOSPHORUS TRICHLORIDE IS 1746.25 g.

Explanation:

Molar mass of PCl3 = ( 31 + 35.5 *3) = 137.5 g/mol

At 7.68 * 10^24 molecules, how many number of mole is present?

6.03 * 10^23 molecules = 1 mole

7.68*10^24 molecules = x mole

x mole = 7.68 *10^24 molecules/ 6.03 *10^23

x mole = 1.27 *10 moles

x mole = 12.7 moles

Using mole = mass / molar mass

mass = mole * molar mass

mass = 12.7 moles * 137.5 g/mol

mass = 1746.25 g

Hence, the mass of 7.68 *10^24 molecules is 1746.25 g

Answer:

[tex]0.688M[/tex]

Explanation:

Hello,

In this case, it is widely acknowledged that strong bases usually correspond to those formed with metals in groups IA and IIA which have relatively high activity and reactivity, therefore, when they are dissolved in water the following dissociation reaction occurs (for calcium hydroxide):

[tex]Ca(OH)_2\rightarrow Ca^{2+}+2OH^-[/tex]

In such a way, for the same volume, we can compute the concentration of hydroxyl ions by simple stoichiometry (1:2 molar ratio):

[tex]0.344\frac{molCa(OH)_2}{L}*\frac{2molOH^-}{1molCa(OH)_2} \\\\0.688\frac{mol OH^-}{L}[/tex]

Or simply:

[tex]0.688M[/tex]

Regards.

Answer:

Predicting the polarity of a bond is the correct answer to this question.

Explanation:

Polar-covalent bonded substances have atoms that are distributed unequally among the central atom. The polarity of this bond is essentially determined by the bound atoms uniformly electronegativities.

To evaluate the polarity using numerical means of a covalent bond, if the result is between 0.4 and 1.7, then the bond is usually polar covalent.

Answer:

E 1: cyclohexene

Explanation:

This reaction is an example of the dehydration of cyclic alcohols. The reaction proceeds in the following steps;

1) The first step of the process is the protonation of the cyclohexanol by the acid. This now yields H2O^+ attached to the cyclohexane ring.

2) the water molecule, which a good leaving group now leaves yielding a carbocation. This now leaves a cyclohexane carbocation which is highly reactive.

3) A water molecule now abstracts a proton from the carbon adjacent to the carbocation leading to the formation of cyclohexene and the regeneration of the acid catalyst. This is an E1 mechanism because it proceeds via a carbocation intermediate and not a concerted transition state, hence the answer.

Answer:

Option A. 1191.49 K

Explanation:

Data obtained from the question include:

The equation for the reaction is given below:

4HCl + O2 —> 2Cl2 + 2H2O

Enthalpy (H) = +280 KJ/mol = +280000 J/mol

Entropy (S) = +235 J/Kmol

Temperature (T) =..?

The temperature at which the reaction will be feasible can be obtained as follow:

Change in entropy (ΔS) = change in enthalphy (ΔH)/T

(ΔS) = (ΔH)/T

235 = 280000/T

Cross multiply

235 x T = 280000

Divide both side by 235

T = 280000/235

T = 1191.49 K

Therefore, the temperature at which the reaction will be feasible is 1191.49 K

Answer:

Formula for the salt: MCl₃

Explanation:

MClₓ → M⁺  +  xCl⁻

We apply the colligative property of boiliing point elevation.

We convert the boiling T° to °C

375.93 K - 273K = 102.93°C

ΔT = Kb . m . i

where ΔT means the difference of temperature, Keb, the ebulloscopic constant for water, m the molality of solution (mol of solute/kg of solvent) and i, the Van't Hoff factor (numbers of ions dissolved)

ΔT = 102.93°C - 100°C = 2.93°C

Kb = 0.512 °C/m

We replace data: 2.93°C = 0.512 °C/m . m . i

i = x + 1 (according to the equation)

22.9 g / (56g/m + 35.45x) = moles of salt / 0.1kg = molality

We have calculated the moles of salt in order to determine the molar mass, cause we do not have the data. We replace

2.93°C = 0.512 °C/m . [22.9 g / (56g/m + 35.45x)] / 0.1kg . (x+1)

2.93°C / 0.512 m/°C = [22.9 g / (56g/m + 35.45x)] / 0.1kg . (x+1)

5.72 m = [22.9 g / (56g/m + 35.45x)]/ 0.1 (x+1)

5.72 . 0.1 / [22.9 g / (56g/m + 35.45x)] = x+1

0.572 / (22.9 g / (56g/m + 35.45x) = x+1

0.572 (56 + 35.45x) / 22.9 = x+1

0.572 (56 + 35.45x) = 22.9x + 22.9

32.03 + 20.27x = 22.9x + 22.9

9.13 = 2.62x

x = 3.48 ≅ 3

Answer:

C) a halohydrin

Explanation:

In organic chemistry, a halohydrin is a compound whereby halogen and hydroxyl functional groups are bonded to adjacent carbon atoms in the molecule. Halohydrins are formed from alkenes such as cyclohexene in this case.

NBS is a very suitable alternative to Br2 in the synthesis of a halohydrin. Recall that the reactive intermediate when bromine reacts with an alkene is the brominium ion which is a three atom ring ion. If excess water is used as the solvent, then the water attacks the brominium ion to yield the product halohaydrin with trans a trans stereochemistry.

Answer:

10.11 mL

Explanation:

Given that :

Total volume of decolorizer = 500 mL

A common recipe is equal parts 95% ethanol and acetone.

So;

The volume of 95% ethanol in the decolorizer = 500mL/2 = 250 mL

Let represent V(ml) for the 99% of ethanol needed to make 95% of the 250 mL of ethanol;

Therefore:

V(ml) × 0.99 = 250 × 0.95

V(ml) × 0.99 = 237.5

V(ml)  = 237.5/0.99

V(ml) = 239.89 mL

Hence; the amount of water to be added to 95% of ethanol = ( 250 -  239.89 )mL = 10.11 mL

Answer:

Explanation:

Following are a few consequences of fossil fuels

1. It causes air pollution.

2. When they are burned, they produce toxic substances which leads to global warming.

3. Waste products are hazardous to public health and environment.

4. They are non - renewable and unsustainable.

5. Drilling fossil fuels is a dangerous process

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Answer:

B

Explanation:

All the elements in a period have valence electrons in the same shell. The number of valence electrons increases from left to right in the period. When the shell is full, a new row is started and the process repeats.

A new period starts when a new neutron cycle starts. Hence, option B is correct.

A period in the periodic table is a row of chemical elements. All elements in a row have the same number of electron shells.

All the elements in a period have valence electrons in the same shell.

The number of valence electrons increases from left to right in the period.

When the shell is full, a new row is started and the process repeats.

Hence, option B is correct.

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Hey there!:

2 Al(NO)₃+ 3 H₂SO₄ → 1 Al₂O₁₂S₃+ 6 HNO₃

Reagents : Al(NO₃)₃ and H₂SO₄

Products : Al₂O₁₂S₃ and HNO₃

Coefficients  : 2 , 3 , 1  and 6

Hope this helps!

Answer:

95.7 g CO to the nearest tenth.

Explanation:

2C + O2 ---> 2CO

Using relative atomic masses:

24 g C produces  2*12 + 2*16 g CO.

So 41 g produces  ( (2*12 + 2*16) * 41  ) / 24

= 95.7 g CO,

Answer:

the same and 14

Explanation:

ed tell chem

Answer: the same 10

Explanation:

Answer:

1.0 mol/L MgCl₂

Explanation:

The formula for osmotic pressure is

Π = icRT

The only difference between the two solutions is their i factor.

MgCl₂

MgCl₂ ⟶ Mg²⁺ + 2Cl⁻

I = 1 + 2 = 3

NaNO₃

NaNO₃ ⟶ Na⁺ + NO₃⁻

i = 1 +1 = 2

MgCl₂ has a greater i value, so its solution has the greater osmotic pressure.

Answer:

Drill bits  

Explanation:

Gemstones such as diamonds are used in drill bits because of their hardness.

They are a 10 on the Mohs scale of hardness, which runs from 0 to 10.

Drill bits are produced from gemstones due to their hardness.

Gemstones are the name given to pieces of minerals  that can be cut and polished valuable accessories.

Gemstones such as diamonds are used in drill bits because of their hardness.

Thus, drill bits are produced using gemstones.

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