Pl hep help help me

Answer:

Hence the Solubility product,  

Ksp = [Ca2+] [Cl-]2  

or, Ksp = (4.5) (9)2  

or, Ksp = 364.5

Explanation:  

Mass of CaCl2 = 4.99 g  

Molar mass of CaCl2 = 110.98 g/mol  

Moles of CaCl2  

= given mass/ molar mass  

= 4.99/ 110.98  

= 0.045  

Volume = 10.0 mL = 0.01 L  

CaCl2 dissociates into its ion as:  

CaCl2 (s)  \rightleftharpoons Ca2+ (aq) + 2 Cl- (aq)  

At 90°C, the solution is saturated with Ca2+ and Cl- ions.

Moles of Ca2+ = Moles of CaCl2 dissolved = 0.045  

Moles of Cl- = 2 x ( Moles of CaCl2 dissolved) = 2 x 0.045 = 0.09

[Ca2+] = Moles/ Volume = 0.045/ 0.01 = 4.5 M  

[Cl-] = 0.09/ 0.01 = 9 M  

Solubility product,  

Ksp = [Ca2+] [Cl-]2  

or, Ksp = (4.5) (9)2  

or, Ksp = 364.5

Answer:

maybe number b is correct. ...thank you

Answer: True

Explanation:

Phosphagens are high energy storage compounds that are usually found in the tissue of animals.

Based on the question, the molecules have similar functions in different organisms such as the fact that they can accept phosphoryl groups from ATP in a situation where the ATP is in excess. Also, they donate phosphoryl groups to ADP in order for the regeneration of ATP.

North America and south africa

Answer:

2,3 Dimethyl hexane

Explanation:

First, start the count from which side is given the CH3 smallest number

first; the longest carbon chain in this compound is 6

and you don't have any double and triple bonds or functional groups so it is Hexane

you start to count from the right side to give the branch molecules the smallest number ..

CH3 = methyl

and you have 2 methyl in this compound ..

and 2 mean you must write ( Di )

you write the name in this way

2,3 Dimethyl hexane

hope this helps you.

stay safe ...

Answer: See explanation

Explanation:

The calibration curve is the method used for the determination of the concentration of a substance such that the unknown sample will be compared to some standard samples of the known concentration.

To prepare a standard (calibration) curve for a spectroscopy experiment, start by preparing (multiple solutions) with (different known concentrations). Then, measure the (absorbance) of each solution at (thesame wavelength) and create a plot of (absorbance vs. concentration) for the measured values. Finally, find the best-fit line of the data set.

Answer:

65.5J

Explanation:

ML=Q

ML=MC(change in temperature)

0.75 X 23000 =0.75 X 351 X C

C= 65.5J

The energy supplied to the lead to melt from 21°c to its melting point is 51521 Joules.

Specific heat is the amount of heat energy supplied to change the temperature of one unit mass of a substance by 1 °C. The SI unit of the specific heat capacity of a substance is J/Kg.

The mathematical expression for the specific heat capacity can be written as:

Q = mCΔT      Where C is the specific heat of the substance.

The specific heat capacity depends upon the starting temperature and is an intensive characteristic of the material.

Given, the melting point of the lead T₂ = 327.5° C

The initial temperature of the lead, T₁ = 21° C

The latent heat of the lead given, L = 230000 J/Kg K

The specific heat of the lead, C = 130 J/Kg K

The heat required to melt the lead from 12°C to 327.5 °C is :

Q = m× [C × (T₂ - T₁) + L ]

Q = 0.75 × [0.130 (327.5 - 21)  + 23000]

Q = 51521 J

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Answer:

% NiCl2 = 24.13%

% water = 78.57%

Explanation:

Mass percentage = mass of solute/mass of solution × 100

According to this question, a solution contains 159 g of NiCl2 in 500 g of water. Hence, mass of the solution is calculated as follows:

Mass of solution = 159g + 500g

Mass of solution = 659g

Therefore;

A) % Mass of NiCl2 in solution = mass of NiCl2/mass of solution × 100

% Mass of NiCl2 in solution = 159/659 × 100

% Mass of NiCl2 in solution = 0.2413 × 100

= 24.13%

B) % Mass of water in solution = mass of water/mass of solution × 100

% Mass of water in solution = 500/659 × 100

% Mass of water in solution = 0.7587 × 100

% Mass of water in solution = 75.87%

Peptide bonds are formed between carboxyl groups of one amino acid and amino group of another dehydration synthesis.

The correct answer is Five Peptide bonds

The peptide of "alanylglutamylalanylglycylalanylleucine" will have four or more peptide bonds.

It will also have free carboxyl groups.

The chain of amino acids is polypeptide.  

Usually C terminal amino acid is the residual at the end of peptide bonds formation.

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Answer:

25.5mL of 0.100M NaOH are needed to reach buffer capacity.

Explanation:

The buffer capacity is reached when the ratio between moles of conjugate base (Sodium acetate) and moles of weak acid (Acetic acid) is 10:

Moles sodium acetate / Moles Acetic acid = 10

The reaction of acetic acid, HA, with NaOH, to produce sodium acetate, NaA is:

HA + NaOH → H2O + NaA

That means the moles of NaOH added = Moles of HA that are being subtracted and moles of NaA that are been produced.

The initial moles of each species is:

Acetic acid:

23.34mL = 0.02334L * (0.147mol / L) = 0.00343 moles Acetic Acid

Sodium Acetate:

33.66mL = 0.03366L * (0.185mol / L) = 0.00623 moles Sodium Acetate

We can write the moles of each species when NaOH is added as:

Moles sodium acetate / Moles Acetic acid = 10

0.00623 moles + X / 0.00343 moles - X = 10

Where X are moles of NaOH added

Solving for X:

0.00623 moles + X = 0.0343 moles - 10X

11X = 0.0281

X = 0.00255 moles of NaOH are needed

In Liters:

0.0255mol NaOH * (1L / 0.100mol) = 0.0255L of 0.100M NaOH are needed =

Answer:

I think third C12/hv is right answer

Answer:

a Leaning towards the speaker

Answer:

the answer is C

Explanation:

The clumping of magnesium sulfate means that the wrong kind of drying agent have been used for the sample.

A drying agent is also referred to as a desiccant. It is a substance that is used to remove moisture from a sample. We must recall that the drying agent to be used must not react with the sample.

Since the magnesium sulfate was found to clump together at the bottom of the flask, it means that the wrong kind of drying agent have been used for the sample.

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Answer:

66.67%

Explanation:

From the given information:

mass of cyclohexane = 2.9949 grams

density of cyclohexane = 0.779 g/mL

Recall that:

Density = mass/volume

∴

Volume = mass/density

So, the volume of cyclohexane = 2.9949 g/ 0.779 g/mL

= 3.8445 mL

Also,

mass of propylbenzene = 1.6575 grams

density of propylbenzene = 0.862 g/mL

Volume of propylbenzene =  1.6575 g/ 0.862 g/mL

= 1.9229 mL

The volume % composition of cyclohexane from the mixture is:

[tex]= (\dfrac{v_{cyclohexane}}{v_{cyclohexane}+v_{propylbenzene}})\times 100[/tex]

[tex]= (\dfrac{3.8445}{3.8445+1.9229})\times 100[/tex]

[tex]= (\dfrac{3.8445}{5.7674})\times 100[/tex]

= 66.67%

Answer:

Explanation:

H = 0.44/1.01 = 0.4356

O = 6.92/16 = 0.4319

This gives a 1:1 ratio. So the closest thing you could say is the formula is 0H

Going to your chemical storage room, you could justify that it is H2O2 or hydrogen peroxide. The question needs one more fact to make the answer certainty.

Answer:

I don't know sorry yyyyyyy6yyyyyyyyyyyyyyyyyyyyyyyyyyy

Answer:

790 years

Explanation:

Given that;

0.693/t1/2 = 2.303/t log [A]o/[A]

So;

t1/2 =half life of carbon-14

t= age of the sample

[A]o= activity of the living sampoke

[A] = activity at time t

0.693/5.73 ×10^3 = 2.303/t log 85/77

1.21 × 10^-4 = 2.303/t log 1.1

1.21 × 10^-4 = 0.0953/t

t= 0.0953/1.21 × 10^-4

t= 790 years (to 2sf)

Explanation:

Answer

Open in answr app

The initial temperature of the coffee T0=100∘C.

The temperature of the room 15∘C.

Let T be the temperature at time t in minutes.

By Newton's law of cooling,

dtdTα(T−15)

∴dtdT=k(T−15)

⇒T−15dT=kdt

⇒∫T−15dT=∫kdt

⇒log(T−15)=kt+logc

⇒log(cT−15)=kt

⇒T−15=cekt

At t=0,T=100

We have 100−15=ce0⇒85=c

Thus we get T−15=85ekt.

When t=5minutes,T=60

⇒60−15=85e5k.

⇒e

Answer:

Explanation:

B.

by breaking the bonds between atoms in molecules

Answer:

23592U+10n→14454Xe+9038Sr+210n

Explanation:

a nuclear reaction for the neutron-induced fission of U−235 to form Xe−144 and Sr−90.

Answer:

Explanation:

From the given information:

The surface area of the can = (30 × 20 × 2) +(20× 15 × 2) +(30 × 15 × 2)

= 1200 + 600 + 900

= 2700 cm²

Since 1 inch² = 0.155 inch²

The surface area in inches² = 2700 × 0.155 inch²

= 418.5 inches²

The total force can be determined by using the expression:

Force = Pressure ×Area

Force = 14.7 psi ×  418.5 inches²

Force = 6151.95 lbs

Yes, the gasoline can will be able to withstand the force.

Answer:

Top layer is Organic (CH2Cl2 and product)

Explanation:

In a solvent mixture, there are usually two phases, the organic phase and the aqueous phase.

It is usual that the organic phase is almost always less dense than the aqueous phase hence the organic phase tend to remain on top of the aqueous phase.

Hence, the top layer is expected to be the organic CH2Cl2 and product.

Explanation:

The conversion factor required to convert moles of helium to atoms of helium is equal to 6.023*10²³ (NA). Helium is a monoatomic gas. Each molecule of helium gas contains one atom of helium. Therefore, one mole of helium gas will contain one mole atoms of helium.

C₆H₁₂O₆ is the molecular formula of gulcozo.

Answer:

59.8 g of PbSO₄.

Explanation:

The balanced equation for the reaction is given below:

Pb + PbO₂ + 2H₂SO₄ —> 2PbSO₄ + 2H₂O

Next, we shall determine the mass of PbO₂ that reacted and the mass of PbSO₄ produced from the balanced equation. This can be obtained as follow:

Molar mass of PbO₂ = 207 + (16×2)

= 207 + 32

= 239 g/mol

Mass of PbO₂ from the balanced equation = 1 × 239 = 239 g

Molar mass of PbSO₄ = 207 + 32 + (16×4)

= 207 + 32 + 64

= 303 g/mol

Mass of PbSO₄ from the balanced equation = 2 × 303 = 606 g

SUMMARY:

From the balanced equation above,

239 g of PbO₂ reacted to produce 606 g of PbSO₄.

Finally, we shall determine the mass of PbSO₄ that will be produced by the reaction of 23.6 g of PbO₂. This can be obtained as follow:

From the balanced equation above,

239 g of PbO₂ reacted to produce 606 g of PbSO₄.

Therefore, 23.6 g of PbO₂ will react to produce = (23.6 × 606) / 239 = 59.8 g of PbSO₄.

Thus, 59.8 g of PbSO₄ were obtained from the reaction.

Answer:

Following are the response to the given question:

Explanation:

In the given scenario, When the balance has never been tainted before the KHP is weighted, which can affect the molar concentration of NaOH because its molarity is directly proportional to the weight including its substance. In this question it is the mistake is systemic because it may be corrected by modifying balancing parameters.

Answer:

CO2

Molar mass: 44.01 g/mol

Explanation:

CO2

Answer

A

Explanation:

Beta radiation is only very dangerous when it is ingested or if there is nothing in the way. The steel should protect you.

Yes, it was beta radiation and the steel was enough to block it. Hence, option A is correct.

Beta radiation is a current of electrons released at a rate exceeding the speed of light, with kinetic energy between 0.2 MeV and 3.2 MeV. Due to their lower mass which is approximately 5.5×[tex]10^{-4}[/tex] amu (9.130×[tex]10^(-24)[/tex], interactions between β-particles and the atoms of pass-through materials are much less frequent than the interactions between 5-007-particles: less than 200 ion pairs are typically formed in each centimetre of the air passage.

When we are working in a lab when radiation alarms go off and we are able to hide inside a steel cabinet, whose sides are about 1.5 inches thick, until the alarm goes off.

Preliminary reports show that the radiation was weakly ionizing and negatively charged. Yes, it was beta radiation and the steel was enough to block it.

Hence, option A is correct.

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