Calculate the mass of dinitrogen tetroxide(N2O4) that contains a billion oxygen atoms. Be sure your answer has a unit symbol if necessary, and round it to significant digits.

Answer:

Explanation:

Out of aspirin, acetaminophen and caffeine, aspirin is an acid because it is acetyl saliciylic acid . Hence it can be tested with litmus paper .

acetaminophen contains phenolic functional group , hence it is a weak acid . It can be tested with any test with which phenol test are done,  like with neutral solution of ferric chloride .

caffeine is weak basic substance . It can also be tested with the help of testing a basic substance .

Answer:

The answer is actually 3. The disorder of a system.

Answer:

3.13%.

Explanation:

The following data were obtained from the question:

Original amount (N₀) = 0.15

Half life (t½) = 2 mins

Number of half-life (n) = 5

Fraction of sample remaining =.?

Next, we shall determine the amount remaining (N) after 5 half-life. This can be obtained as follow:

Amount remaining (N) = 1/2ⁿ × original amount (N₀)

NOTE: n is the number of half-life.

N = 1/2ⁿ × N₀

N = 1/2⁵ × 0.15

N = 1/32 × 0.15

N = 0.15/32

N = 4.69×10¯³

Therefore, 4.69×10¯³ is remaining after 5 half-life.

Finally, we shall the fraction of the sample remaining after 5 half-life as follow:

Original amount (N₀) = 0.15

Amount remaining (N) = 4.69×10¯³

Fraction remaining = N/N₀ × 100

Fraction remaining = 4.69×10¯³/0.15 × 100

Fraction remaining = 3.13%

Answer:

I literally got this from google.

Explanation:

In ordinary air, sodium metal reacts to form a sodium hydroxide film, which can rapidly absorb carbon dioxide from the air, forming sodium bicarbonate. ... In a comparatively dry atmosphere, sodium burns quietly, giving off a dense white caustic smoke, which can cause choking and coughing.

Happy almost Halloween! :)

Answer:

the answer is B

Explanation:

When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges

Answer:

[H+] = 7.576x10⁻⁴M

pH = 3.12

Explanation:

Based on the equilibrium of the nicotinic acid in water:

HC6H4NO2(aq) + H2O(l) ⇄ C6H4NO2-(aq) + H3O+(aq)

Ka = [C6H4NO2-] [H3O+] / [HC6H4NO2]

As both C6H4NO2-(aq) and H3O+(aq) comes from the same equilibrium, we can approximate their concentration as X and replace:

Ka = [C6H4NO2-] [H3O+] / [HC6H4NO2]

1.4x10⁻⁵ = [X] [X] / [0.041M]

5.47x10⁻⁷ = X²

And as pH is defined as -log [H⁺]

Answer:

The Answer is eight.

Explanation:

Sorry if it's too late and it doesn't help! But I hope you have a magnificent day! :3

Answer:

8

Explanation:

I had this question on my quiz and got it right.

Answer:..

Explanation:

Answer:

100 joules​

Explanation:

The mechanical energy (M.E) of an object describes the objects ability to do work. The mechanical energy encompasses the object's energy due to its position (potential energy) and its energy due to motion (kinetic energy).

Therefore,

M.E = K.E + P.E

According to this question, potential energy (P.E) of the roller coaster is 50J and the kinetic energy (K.E) is also 50J. Hence, the mechanical energy (M.E) is

M.E = 50J + 50J

M.E = 100J

If the P.E and K.E of a roller coaster is 50 Joules respectively, the mechanical energy of the roller coaster is 100 Joules.

Given the following data:

To find the mechanical energy of the roller coaster:

The mechanical energy of a physical object or body is the total sum of the potential energy (P.E) and kinetic energy (K.E) possessed by an object.

Mathematically, mechanical energy is given by the formula;

Substituting the given parameters into the formula, we have;

[tex]M.E = 50 + 50[/tex]

Mechanical energy (M.E) = 100 Joules.

Therefore, the mechanical energy of the roller coaster is 100 Joules.

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Answer:

4.5 × 10⁻⁹

Explanation:

Step 1: Write the reaction for the solution of CaCO₃

CaCO₃(s) ⇄ Ca²⁺(aq) + CO₃²⁻(aq)

Step 2: Convert the solubility of CaCO₃ from g/L to mol/L

We will use the following conversion factors:

[tex]\frac{0.00067 gCaCO_3}{100mLSol} \times \frac{1molCaCO_3}{100.09gCaCO_3} \times \frac{1000mLSol}{1LSol} = 6.7 \times 10^{-5} M[/tex]

Step 3: Calculate the solubility product constant (Ksp)

To relate Ksp and the molar solubility (S), we need to make an ICE chart.

        CaCO₃(s) ⇄ Ca²⁺(aq) + CO₃²⁻(aq)

I                               0                0

C                            +S               +S

E                              S                 S

The solubility product constant is:

Ksp = [Ca²⁺].[CO₃²⁻] = S² = (6.7 × 10⁻⁵)² = 4.5 × 10⁻⁹

Answer: The equilibrium concentration of [tex]H_2(g)[/tex] at 700 degrees Celsius is 0.0012 M

Explanation:

Equilibrium constant is defined as the ratio of concentration of products to the concentration of reactants each raised to the power their stoichiometric ratios. It is expressed as [tex]K_c [/tex]

Moles of  [tex]H_2S[/tex] = 0.29 mole

Volume of solution = 3.0 L

Initial concentration of [tex]H_2S[/tex] = [tex]\frac{0.29mol}{3.0L}=0.097M[/tex]

The given balanced equilibrium reaction is,

                    [tex]2H_2S(g)\rightleftharpoons 2H_2(g)+S_2(g)[/tex]

         Initial conc.         0.097 M           0M          0M

At eqm. conc.    (0.097-2x) M            (2x) M   (x) M

The expression for [tex]K_c[/tex] is written as:

[tex]K_c=\frac{[H_2]^2\times [S_2]}{[H_2S]^2}[/tex]

[tex]K_c=\frac{(2x)^2\times x}{(0.097-2x)^2}[/tex]

[tex]9.30\times 10^{-8}=\frac{(2x)^2\times x}{(0.097-2x)^2}[/tex]

[tex]x=0.00060[/tex]

Equilibrium concentration of [tex][H_2][/tex]= 2x= [tex]2\times 0.00060=0.0012M[/tex]

Answer:

make an observation that describes a problem

Explanation:

Answer:

The first step in the Scientific Method is to make objective observations.

Explanation:

....-

Answer:

The energy of each transition is approximately [tex]1.98\times 10^{-19}\; \rm J[/tex].

The frequency of photons released in such transitions is approximately [tex]3.00\times 10^{14}\; \rm Hz[/tex].

Explanation:

The Rydberg Equation gives the wavelength (in vacuum) of photons released when the electron of a hydrogen atom transitions from one main energy level to a lower one.

The Rydberg Equation gives the following relation:

[tex]\displaystyle \frac{1}{\lambda_\text{vac}} = R_\text{H} \cdot \left(\frac{1}{{n_2}^2}} -\frac{1}{{n_1}^2}\right)[/tex].

Rearrange to obtain and expression for [tex]\lambda_\text{vac}[/tex]:

[tex]\displaystyle \lambda_\text{vac} = \frac{1}{\displaystyle R_\text{H}\cdot \left(\frac{1}{{n_2}^2} - \frac{1}{{n_1}^2}\right)}[/tex].

In this question, [tex]n_1 = 7[/tex] while [tex]n_2 = 3[/tex]. Therefore:

[tex]\begin{aligned} \lambda_\text{vac} &= \frac{1}{\displaystyle R_\text{H}\cdot \left(\frac{1}{{n_2}^2} - \frac{1}{{n_1}^2}\right)} \\ &\approx \frac{1}{\displaystyle 1.09678 \times 10^{7}\; \rm m^{-1} \cdot \left(\frac{1}{3^2} - \frac{1}{7^2}\right)} \approx 1.0 \times 10^{-6}\; \rm m \end{aligned}[/tex].

Note, that [tex]1.0\times 10^{-6}\; \rm m[/tex] is equivalent to [tex]1000\; \rm nm[/tex]. That is: [tex]1.0\times 10^{-6}\; \rm m = 1000\; \rm nm[/tex].

Look up the speed of light in vacuum: [tex]c \approx 3.00\times 10^{8}\; \rm m \cdot s^{-1}[/tex]. Calculate the frequency of this photon:

[tex]\begin{aligned} f &= \frac{c}{\lambda_\text{vac}} \\ &\approx \frac{3.00\times 10^{8}\; \rm m\cdot s^{-1}}{1.0\times 10^{-6}\; \rm m} \approx 3.00 \times 10^{14}\; \rm Hz\end{aligned}[/tex].

Let [tex]h[/tex] represent Planck constant. The energy of a photon of wavelength [tex]f[/tex] would be [tex]E = h \cdot f[/tex].

Look up the Planck constant: [tex]h \approx 6.62607 \times 10^{-34}\; \rm J \cdot s[/tex]. With a frequency of [tex]3.00\times 10^{14}\; \rm Hz[/tex] ([tex]1\; \rm Hz = 1\; \rm s^{-1}[/tex],) the energy of each photon released in this transition would be:

[tex]\begin{aligned}E &= h \cdot f \\ &\approx 6.62607 \times 10^{-34}\; \rm J\cdot s^{-1} \times 3.00 \times 10^{14}\; \rm s^{-1} \\ &\approx 1.98 \times 10^{-19}\; \rm J\end{aligned}[/tex].

The energy of the transition between n = 7 and n = 3  is 1.96 × 10^-19 J while the frequency is 3 × 10^14 Hz.

Using the Rydberg Equation for energy;

ΔE = -RH(1/n^2final - 1/n^2initial)

Given that;

nfinal = 3

ninitial = 7

RH = 2.18 × 10^-18 J

ΔE = - 2.18 × 10^-18(1/3^2 - 1/7^2)

ΔE = - 2.18 × 10^-18(0.11 - 0.02)

ΔE = - 1.96 × 10^-19 J

For the second part;

Since the wavelength is 1000nm, we have;

λ = 1000nm

c = 3 × 10^8 m/s

f = ?

c = λf

f = c/λ

f = 3 × 10^8 m/s/1000 × 10^-9 m

f = 3 × 10^8 m/s/ 1 × 10^-6 m

f = 3 × 10^14 Hz

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Answer:

See explanation

Explanation:

a) -About 1-2 drops of the unknown is dissolved in approximately 1 mL of analytical grade acetone standard solution. The test solution is added and shaken thoroughly.  If a positive test is not immediately observed, the set should be allowed to stand for 1-2 minutes. A positive result means the appearance of a green color.

b) The functional groups that can be distinguished by the test are alcohols and aldehydes.

Aldehydes give a positive test to chromic acid but ketones do not.

Primary and secondary alcohols give a positive test to chromic acid but tertiary alcohols do not.

c) Chromic Acid Test involves Cr in the +6 oxidation state. A positive test implies the reduction of orange Cr^6+ to green chromium Cr^3+.

d) The compounds were not shown but this image attached from lumen learning summarizes the reaction mechanism of chromic acid test.

Answer:

Near the boiling point of the solvent

Explanation:

The process of recrystallization is hinged on the fact that the amount of solute that can be dissolved by a solvent increases with temperature. The process involves creation of a solution by dissolving a solute in a solvent at or near its boiling point.  At the boiling point of the solvent, the solute has a greater solubility in the solvent; not much volume of  the hot solvent is required to dissolve the solute.

Before the solution is later cooled, you can now filter out insoluble impurities from the hot solvent. The quantity of the original solute drops appreciably because impurities have been removed. At this lower temperature, the solution becomes saturated and the solute can no longer be held in solution hence it forms pure crystals of solute, which can be recovered.

Recrystallization must be carried out using the proper solvent. The solute must be relatively insoluble in the solvent at room temperature but more soluble in the solvent at elevated temperature.

Answer:

organ system

Explanation:

Answer:

B) organ

Explanation:

Moles of [tex]H_2O[/tex] ,

[tex]n_{H_2O}=\dfrac{42}{2\times 1 + 16}=\dfrac{42}{18}\\\\n_{H_2O}=2.33\ moles[/tex]

Moles of acetic acid [tex]HCH_3CO_2[/tex] ,

[tex]n_{A.A}=\dfrac{77}{1 + 12 + 3 + 12 + 16\times 2}=\dfrac{77}{60}\\\\n_{A.A}=1.28\ moles[/tex]

Mole fraction of water :

[tex]M.F_{H_2O}=\dfrac{n_{H_2O}}{n_{H_2O}+n_{A.A}}\\\\M.F_{H_2O}=\dfrac{2.33}{2.33+1.28}\\\\M.F_{H_2O}=0.645[/tex]

Therefore, mole fraction of water in this solution is 0.645 .

Hence, this is the required solution.

Answer:

1) 97.6%

2) No the purity is not acceptable because the standard is 99.5% purity.

3) Yes I will repeat the titration experiment to confirm my result.

Explanation:

Equation of the reaction;

C7H6O2(aq) + NaOH(aq) ---------> C7H5ONa(aq) + H2O(aq)

From the information provided;

Number of moles of NaOH reacted = concentration × volume = 20.15/1000 × 0.500 = 0.01 moles

From the reaction equation;

1 mole of C7H6O2 reacts with 1 mole of NaOH

Hence 0.01 moles of C7H6O2 will react with 0.01 moles of NaOH

Mass of C7H6O2 reacted = number of moles of C7H6O2 × molar mass of C7H6O2

Molar mass of C7H6O2 = 122.12 g/mol

Mass of C7H6O2 reacted = 0.01 moles × 122.12 g/mol = 1.22 g

Percentage by mass of pure C7H6O2 in the impure sample = 1.22/1.250 × 100 = 97.6 %

Answer:

C.

Explanation:

You can use the series of elimination for this. First, you look at A. Technology is not an understanding of something new, so we cross that out. Second, you look at B. Technology isn't a series of steps, so we can mark that one off. Third, you look at C. Technology is something created using science for use by society, so we can keep that in mind. Lastly, we check D. Technology doesn't match up to the definition, so we can cross that one out. The answer that would make the most sense would be D.

Answer:

15.2mL of the 0.10M sodium formate solution and 4.8mL of the 0.10M formic acid solution.

Explanation:

To find the pH of a buffer based on the concentration of the acid and conjugate base we must use Henderson-Hasselbalch equation:

pH = pKa + log [A⁻] / [HA]

Where [A⁻] could be taken as moles of the sodium formate and [HA] moles of the formic acid

4.25 = 3.75 + log [A⁻] / [HA]

0.5 = log [A⁻] / [HA]

3.162 = [A⁻] / [HA] (1)

As both solutions are 0.10M and you want to create 20mL of the buffer, the moles are:

0.10M  * 20x10⁻³L =

2x10⁻³moles = [A⁻] + [HA] (2)

Replacing (2) in (1):

3.162 = 2x10⁻³moles - [HA] / [HA]

3.162 [HA] = 2x10⁻³moles - [HA]

4.162[HA] = 2x10⁻³moles

[HA] = 4.805x10⁻⁴ moles

[A⁻] = 2x10⁻³moles - 4.805x10⁻⁴ moles = 1.5195x10⁻³moles

That means, to create the buffer you must add:

[A⁻] = 1.5195x10⁻³moles * (1L / 0.10mol) = 0.0152L =

[HA] = 4.805x10⁻⁴ moles * (1L / 0.10mol) = 0.0048L =

Answer:

3

Explanation:

I wish you the best, its three or 2

Answer:

2

Explanation:

Edge 2021

Answer:

D

Explanation:

Identifying unique features of evidence

A laboratory is a place where scientific investigations and experiments are conducted. Observing a phenomenon in the lab includes identifying unique features of evidence. Thus, option D is correct.

An observation is said to be the deduction that is seen or heard and is due to the actions of the process or event that are gained from the information from a conducted experiment.

It is an important factor in an experiment and research and is used in the lab to falsify or prove the hypothesis. It is made based on the experimental setup and involves various steps.

The observations are used to draw conclusions and inferences based on the detailed identification of the characteristics of the evidence. The evidence supports the observation.

Therefore, option D. the features of evidence are the correct option.

Learn more about observations here:

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#SPJ2

Answer:

ARSENIC

Explanation:

It has an atomic number of 33

Answer:

1.14 M

Explanation:

Let's consider the following reaction.

butane ⇄ isobutane

We can use the concentrations at equilibrium to calculate the equilibrium constant.

Kc = [isobutane] / [butane]

Kc = 2.5 / 1.0

Kc = 2.5

If we add 0.50 M of isobutane, we get [isobutane] = 2.5 + 0.50 = 3.0 M.

This will be an initial concentration in an ICE chart.

        butane ⇄ isobutane

I           1.0              3.0

C         +x                -x

E        1.0+x           3.0-x

The equilibrium constant is:

Kc = 2.5 = [isobutane] / [butane]

2.5 = (3.0-x) / (1.0+x)

2.5 + 2.5x = 3.0-x

x = 0.14

The equilibrium concentration of butane is:

[butane] = 1.0+x = 1.14 M

Answer:

Organic

Explanation:

Edge student

Answer:

[tex]0.326\frac{N}{cm^2}[/tex]

Explanation:

Hello.

In this case, considering that 1 atm equals 1.01 kPa, we can compute the pressure in kPa first as shown below:

[tex]2.25atm*\frac{1.01kPa}{1atm} =3.26kPa[/tex]

Now, we convert kPa to Pa, considering 1 kPa equals 1000 Pa:

[tex]3.26kPa*\frac{1000Pa}{1kPa}=3260Pa[/tex]

Now, since Pa is equal to N/m², and 1 m equals 100 cm, the pressure in newton per square centimeter turns out:

[tex]3260\frac{N}{m^2}*(\frac{1m}{100cm})^2 \\\\0.326\frac{N}{cm^2}[/tex]

Best regards.

Answer:

Changes in environment, food source changes and disease?

Explanation:

I dont know what the answer choices are

Answer:

changes in the environment

Explanation:

like digging big holes.

Hope this helps!