Perform the calculation, rounding your answer to the proper number of significant figures.
0.867 +3.72 + 18.0045 =

Answer:

D will brain cancer eventually be curable?

Explanation:

Answer:

Do foods that contain a high amount of fat cause brain cancer?

Explanation:

Do foods that contain a high amount of fat cause brain cancer?

Answer:

Kilogram

Explanation:

The metric system is the Kilogram, meter, second system. These are fundamental quantities of the metric system.

Kilogram, the unit of mass always carries the prefix 'kilo' in its SI unit. Kilogram is the SI unit of mass. Hence, the fundamental unit on the metric system that always has a prefix in front of it is kilogram.

Answer:

The pH of a solution of 0.00278 M of HClO₄ is 2.56

Explanation:

pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance and is calculated as:

pH= - log [H⁺]= - log [H₃O⁺]

On the other hand , a Strong Acid is that acid that in an aqueous solution dissociates completely. In other words, a strong acid completely dissociates into hydrogen ions and anions in solution.

HClO₄ is a strong acid, so in aqueous solution it will be  totally dissociated. Then, the concentration of protons is equal to the initial concentration of  acid and the pH will be calculated:

pH= - log 0.00278

pH= 2.56

The pH of a solution of 0.00278 M of HClO₄ is 2.56

Answer:

Product one: (2S, 3R)-3-chloro-2-butanol

Product two: (3S, 2R)-3-chloro-2-butanol

Explanation:

The IUPAC  name of the products following IUPAC guidelines are :

Product one: (2S, 3R)-3-chloro-2-butanol

Product two: (3S, 2R)-3-chloro-2-butanol

attached below is a pictorial representation of the formation of the 3-chloro-2-butanol via backside attack of Nucleophile

Answer:

The answer is

Explanation:

Density of a substance is given by

From the question

mass of block = 600 g

volume = 82.1 cm³

Substitute the values into the above formula and solve for the Density

That's

We have the final answer as

Hope this helps you

Answer : The density of wood is 1.11 g/cm³.

The piece of wood will not float in water.

Explanation : Given,

Mass of wood = 80.0 g

Length of piece of wood = 3.0 cm

Width of piece of wood = 6.0 cm

Height of piece of wood = 4.0 cm

First w have to calculate the volume of wood.

Volume of wood = Length × Width × Height

Volume of wood = 3.0 cm × 6.0 cm × 4.0 cm

Volume of wood = 72.0 cm³

Now we have to calculate the density of wood.

[tex]\text{Density of wood}=\frac{\text{Mass of wood}}{\text{Volume of wood}}[/tex]

Now putting all the given values in this formula, we get:

[tex]\text{Density of wood}=\frac{80.0g}{72.0cm^3}[/tex]

[tex]\text{Density of wood}=1.11g/cm^3[/tex]

As we know that there are two conditions to determine whether the object will float or sink in a liquid.

The density of water is 1 g/cm³.

From this we conclude that the density of wood is more than water that means the wood will sink in water.

Pseudo in chemistry means a reaction which is not first-order reaction naturally but made first order by increasing or decreasing the concentration of one or other reactant is known as Pseudo first order reaction.Pseudo means "fake".

Answer:

Chemists make observations on the macroscopic a scale that lead to conclusions about microscopic features

Explanation:

Many important chemical observations are made on the macroscopic scale. This is because, many of the scientific equipments available are not presently able to provide direct evidence about microscopic processes. Evidences obtained from macroscopic observations could serve as important insights into the nature of certain microscopic processes.

This is evident in the study of the structure of the atom. Most of the evidences that led to the deduction of the atomic structure were obtained from macroscopic evidence but ultimately provided important information about the microscopic structure of the atom.

It is true that Chemists make observations on the macroscopic  scale that lead to conclusions about microscopic  features.

Macroscopic observations are those that humans are able to see with their naked eyes.

Observing macroscopic phenomenon, scientists are able to come up with conclusions at a microscopic level because anything that happens at the macroscopic level is as a result of microscopic occurrences on a much smaller level.

Examples of macroscopic occurrences that lead to microscopic conclusions:

In conclusion, the observations we make on a macroscopic scale allow for microscopic conclusions.

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Answer:

[tex]NaBF_4[/tex]

Explanation:

In this reaction, we must exchange the amino group ([tex]NH_2[/tex]) for a fluorine atom ([tex]F[/tex]). Also, the first step in this reaction is the addition of nitrous acid.

We must remember that the amino group in the presence of nitrous acid produces a diazonium salt. The [tex]N_2[/tex] group is a very good leaving group and many benzene derivatives can be produced from this intermediate (see figure 1).

If what we want is to bond a fluorine atom we must use [tex]NaBF_4[/tex] to be able to produce m-ethylfluorobenzene (see figure 2).

I hope it helps!

Answer:

[tex]Final\ Mass = 17.560943085g[/tex]

Explanation:

Given

[tex]Sample\ Mass = 6.814g[/tex]

[tex]Additional\ Mass = 0.08753g[/tex]

[tex]Yield = 7.6335[/tex]

Required

Determine the final mass

First we need to determine the total mass after the sample mass is added to an additional sample;

[tex]Total\ Mass = Additional\ Mass + Sample\ Mass[/tex]

[tex]Total\ Mass = 0.08753g + 6.814g[/tex]

[tex]Total\ Mass = 6.90153g[/tex]

Next, divide the total mass by 3

[tex]New\ Mass = \frac{Total\ Mass}{3}[/tex]

[tex]New\ Mass = \frac{6.90153g}{3}[/tex]

[tex]New\ Mass = 2.30051g[/tex]

The final mass is calculated as follows;

[tex]Final\ Mass = New\ Mass * Yield[/tex]

[tex]Final\ Mass = 2.30051g * 7.6335[/tex]

[tex]Final\ Mass = 17.560943085g[/tex]

Hence, the final mass is 17.560943085g

Answer:

[tex]p_{PCl_3}=0.693atm\\\\p_{Cl_2}=0.693atm\\\\p_{PCl_5}=0.967atm[/tex]

Explanation:

Hello,

In this case, for the given reaction, the equilibrium expression is:

[tex]Kp=\frac{p_{PCl_3}p_{Cl_2}}{p_{PCl_5}}[/tex]

But in terms of the reaction extent [tex]x[/tex] can also be written as:

[tex]Kp=\frac{x*x}{p_0-x}[/tex]

Whereas the initial pressure is 1.66 atm. Thus, we write:

[tex]0.497=\frac{x^2}{1.66atm-x}[/tex]

And solving for [tex]x[/tex] we obtain:

[tex]x=0.693atm[/tex]

Therefore, the pressure of each species at equilibrium is:

[tex]p_{PCl_3}=x=0.693atm\\\\p_{Cl_2}=x=0.693atm\\\\p_{PCl_5}=1.66atm-0.693atm=0.967atm[/tex]

Best regards.

Answer:

The ancient Greeks were the first to use the word atom,which means indivisible,to describe the smallest particle of any substance. Its actual existence was not established until yhe nineteenth century when John Dalton, an English chemist,put forward a theory to describe the nature of the atom.The atom is now considered to be the basic unit of simple substances or elements.An atom is the smallest particle of an element which can take part in a chemical reaction or an atom is the smallest part of an element that can ever exist and still possess the chemical properties of that element.

Answer:

In order to determine the mass of a substance given the volume, we require the density. The density of iron is 7.87 grams/cm³

Density = mass / volume

Mass = density * volume

Mass = 7.87 * 4.8

37.776 grams of iron are present in the cube

The density of the substance represents the relation of the mass to the volume of the substance. The mass of a pure iron cube of density 7.87 grams/cm³ is calculated to be 37.632 grams.

Mass is the amount of the substance contained that when gets divided by the volume in liters, milliliters or cubic centimeters gives the density of the substance. The mass of the substance can be in grams, kilograms, milligrams, etc.

The mass (m) is the multiplication product of the density (D) and volume (V) of the substance. Mass measures the amount whereas density measures the space occupied by the volume of the substance.

Given,

Density of iron cube (D) = 7.87 grams/cm³

Volume of cube (V) = 4.80 cm³

The formula is given as:

Density = mass ÷ volume

Mass = density × volume

Substituting values from above, the mass in grams of the iron cube is calculated as:

mass = 7.87 grams/cm³ × 4.80 cm³

mass = 37.632 grams

Therefore, the iron cube with a density of 7.87 grams/cm³ has a mass of 37.632 grams.

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Your question has been heard loud and clear

CH3Cl + AgCN = CH3CN + AgCl

A= CH3CN+AgCl

Thank you

Answer:

% m/m (sugar) = 7.77 %

Explanation:

Step 1: Given data

Mass of sugar (solute): 17.5 g

Mass of solution: 225 g

Step 2: Calculate the percent by mass of sugar

The percent by mass of sugar is equal to the mass of sugar divided by the mass of the solution times 100%.

% m/m (sugar) = (mass of sugar / mass of solution) × 100%

% m/m (sugar) = (17.5 g / 225 g) × 100%

% m/m (sugar) = 7.77 %

Answer:

Oxidation Occurs after the addition of the uncoupler 2,5 dinitrophenol

Explanation:

The chemical compound that is Dinitrophenol (DNP). The compound has the chemical formula of HOC6H3(NO2)2. The compound helps during Adenosine triphosphate synthesis by making sure that there is enough hydrogen ion for the synthesis.  

Therefore, if the " presence of oxygen and in the absence of ADP". Thus,  When the uncoupler 2,4-dinitrophenol is added to a suspension of normal mitochondria five minutes after an oxidizable substrate has been added, there is going to be OXIDATION ON THE SUBSTRATE AFTER THE ADDITION WHICH IS GOING TO BE RAPID AFTER SOME TIME.

Answer:

b) dipole-dipole forces

Explanation:

Hello,

In this case, it is widely known that NBr₃ is a polar molecule since it has a trigonal pyramidal geometrical structure in which nitrogen has a lone pair of electrons and three bonds with three bromine atoms which are polar, due to the fact that bromine is less electronegative than nitrogen. causing the overall compound to be polar, as the dipoles are not cancelled. Therefore, the strongest forces are b) dipole-dipole forces among dipoles.

Regards.

Answer: 27.1 g of solid chromium(III) acetate should be added.

Explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per liter of the solution.

[tex]Molarity=\frac{n\times 1000}{V_s}[/tex]

where,

n = moles of solute

[tex]V_s[/tex] = volume of solution in ml

moles of [tex]Cr(CH_3COO)_3[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{xg}{229g/mol}[/tex]

Now put all the given values in the formula of molality, we get

[tex]0.237=\frac{xg\times 1000}{229g/mol\times 500ml}[/tex]

[tex]x=27.1[/tex]

Therefore, 27.1 g of solid chromium(III) acetate should be added.

Answer:

The answer is

Explanation:

The kinetic energy of a body can be found by using the formula

where

m is the mass

v is the velocity / speed

From the question

mass = 10 kg

velocity = 12 m/s

Substitute the values into the above formula and solve

That's

We have the final answer as

Hope this helps you

Answer:

[tex]m=2.575g[/tex]

Explanation:

Hello,

In this case, since the density is defined as the ratio of the mass and volume:

[tex]\rho =\frac{m}{V}[/tex]

We can compute the mass of blood as follows:

[tex]m=\rho *V=1.03g/L*2.500L\\\\m=2.575g[/tex]

Best regards.

The correct options are: shining dim blue light on a strip of metal, and

shining bright blue light on a strip of metal produces a photoelectric

effect. Hence, option (C) and (D) are correct

The photoelectric effect is the emission of electrons from a metallic surface when light of determined frequency shines over the metallic surface.

The electrons are ejected from the metal surface when the frequency of the incident light beam reaches a minimum frequency (threshold).

The frequency of light is  related to the color of light (not with the intensity).

The red light is at the lower frequency end and the violet light at the higher frequency end of the spectrum of visible light.

That condition  is considered in the given statement when it tells that "Blue light waves have more energy than red light waves" , since the frequency is directly related to the energy, by the Planck equation:

Energy of a photon (light) = Planck constant × frequency.

The intensity of the light (if the light is dim or bright) does not influence the photoelectric effect.

Hence, you conclude that the light with more energy (the blue light) either dime or bright will most likely produce the photoelectric effect.

That is why the correct options are:

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Answer:

Explanation:

H₂A    ⇄   HA⁺  +  A⁻

K₁ = [ HA⁺] [A⁻ ] / [ H₂A ]

HA⁺ ⇄  H⁺ + A⁻

K₂ = [ H⁺] [ A ⁻ ] / [ HA⁺ ]

H₂A           ⇄   HA⁺      +        A⁻

.100                     0                 0

.100 - C                C                C

K₁ = [ HA⁺] [A⁻ ] / [ H₂A ]

Putting the values

1.00 x 10⁻⁴ =   C X C / .1  -  C

10⁻⁵ - 10⁻⁴ C = C²

C²  + 10⁻⁴ C - 10⁵ = 0

C = 8 X 10⁻² M

So concentration of H₂A that is [ H₂A ]  = 1 - C =   0 .1 - 8 X 10⁻² M

= .02 = 2 x 10⁻² M

NaHA    ⇄   Na⁺ + HA⁻

NaHA is a strong acidic salt  so it will ionise 100 %

NaHA    ⇄   Na⁺ + HA⁻

.1                   .1         .1  

concentration of HA⁻  =  .1 M

Na₂A ⇄  2Na⁺  + A⁻²

Na₂A is also a strongly ionic  salt so it will dissociate 100 % .

Na₂A ⇄  2Na⁺  + A⁻²

.1               .1          .1  

concentration of A⁻²  = .1 M  

HA⁺    ⇄       H⁺   +     A⁻

8 X 10⁻²         C₁        C₁  

K₂ = [ H⁺] [ A ⁻ ] / [ HA⁺ ]

Putting the values

1.00 x 10⁻⁸ = C₁ X C₁ /  C

1.00 x 10⁻⁸ = C₁²  /  8 X 10⁻²

C₁² = 8 x 10⁻¹⁰

C₁ = 2.828 x 10⁻¹⁰

[ H⁺]  = 2.828 x 10⁻¹⁰

pH = - log  [ H⁺]  = - log 2.828 x 10⁻¹⁰

= 10 - log 2.828

= 10 - .45

= 9.55 .

Answer:

(CH3)2CHCH2CHO

Explanation:

The reaction sequence begins with the reaction of isopropanol with phosphorus tribromide to yield isopropyl bromide. This is followed by reaction with Magnesium in ether solution giving a grignard reagent, isopropyl magnesium bromide. This is now attacked by oxirane and the epoxide ring opens, hydrolysis of the product, followed by oxidation using pyridinium chlorochromate (PCC) yields the final product- (CH3)2CHCH2CHO

The detailed reaction mechanism is attached to this answer.

Answer:

The energy of the orbitals are the same

Explanation:

For a free metal ion, all the d-orbitals are of the same energy. The five d-orbitals are said to be five fold degenerate in the free metal ion. Hence all the d-orbitals will possess the same energy irrespective of which one is first filled.

In an octahedral or tetrahedral crystal field, the d-orbitals will loose their degeneracy and become different in energy based on their orientation towards the ligands.

The answers are A. Pseudoscience is often based only on opinions; D. Pseudoscience often involves explanations of beliefs; E. Pseudoscience includes subjective ideas.

Explanation:

Pseudosciences comprises disciplines or theories that do not follow scientific standards but claim to be factual. This includes areas such as clairvoyance or astrology because this is not based on evidence but subjectivity. Indeed, the base of most pseudosciences are personal beliefs, opinions, or subjective ideas. Moreover, complex theories or methods are created to try to explain these beliefs, but because they do not follow scientific standards they are not considered as valid. In this context, options A, D, and E are correct.

Answer:

A is the correct answer

A is the correct answer

Answer:

Vanderwaals forces

Explanation:

CBr4 is a nonpolar molecule, nonpolar molecules usually possess vanderwaals forces between their molecules as their main attractive force.

CBr4 is nonpolar because the tetrahedral arrangement of the C-Br bonds cancel out the individual dipole moments of each C-Br bond thereby making the compound nonpolar, hence the answer above.

6.02 x10^23 atom  

3.5g x 1mol/63.55g Cu x 6.02 x 10^23/ 1mol=

3.32 x 10^22 atoms

Answer:

here is something I know

hope it works :)

Explanation:

Visible light has a wavelength range from ~400 nm to ~700 nm. Violet light has a wavelength of ~400 nm, and a frequency of ~7.5*1014 Hz. Red light has a wavelength of ~700 nm, and a frequency of ~4.3*1014 Hz.

Answer:

1.8 × 10⁻⁴ mol M/s

Explanation:

Step 1: Write the balanced reaction

2 Br⁻ ⇒ Br₂

Step 2: Establish the appropriate molar ratio

The molar ratio of Br⁻ to Br₂ is 2:1.

Step 3: Calculate the rate of appearance of Br₂

The rate of disappearance of Br⁻ at some moment in time was determined to be 3.5 × 10⁻⁴ M/s. The rate of appearance of Br₂ is:

3.5 × 10⁻⁴ mol Br⁻/L.s × (1 mol Br₂/2 mol Br⁻) = 1.8 × 10⁻⁴ mol Br₂/L.s