How many molecules are in 2.0 grams of
Na2SO4?

Answer:

Explanation:

The specific rotation of the sample is -2 degrees/0.2 g/mL of mixture

This equals -10 degrees/g/mL of sample.

let the proportion of the R (+) enantiomer be x. The proportion of the S (-) enantiomer in the mixture will be given by (1-x).

specific rotation of the mixture = proportion of R enantiomer* its specific rotation + proportion of S enantiome * its specific rotation

i.e.

-10 = x *(+20) + (1-x)*(-20)

-10 = 20x-20 + 20x

-10+20 = 40x

+10 = 40 x

x=10/40 = 25%

Since the proportion of the other enantiomer is 1-x, it is 0.75 or 75%

So the mixture contains 25% R, 75% S, giving you an excess of 50%.

Answer:

10%

Explanation:

Enantiomeric excess is a way of describing how optically pure a mixture is by calculating the purity of the major enantiomer. It can range from 0%-100%. Enantiomeric excess ( ee ) can also be defined as the absolute difference between the mole fractions of two enantiomers.

Enantiomeric excess is also called optical purity. This is because chiral molecules cause the rotation of plane-polarized light and are said to be optically active. An enantiomerically pure sample has an enantiomeric excess of 100 percent

Enantiomeric excess = observed specific rotation/specific rotation of the pure enantiomer x 100

From the data given in the question;

observed specific rotation= -2°

specific rotation of the pure enantiomer = +20°

Therefore;

ee= 2/20 ×100

ee= 10%

Answer:

2.4 × 10⁻⁴ M/s

Explanation:

Step 1: Given data

Step 2: Convert the time to seconds

We will use the relationship 1 min = 60 s.

\(1.5min \times \frac{60s}{1min} =90s\)

Step 3: Calculate the rate of the reaction

Since A is a reactant, we will calculate the rate of the reaction (r) using the following expression.

\(r=-\frac{\Delta [A]}{t} =-\frac{[A]-[A]_0}{t} =-\frac{0.032M-0.054M}{90s} =2.4 \times 10^{-4} M/s\)

The correct categorization of the solutions is:a. KCl - Neutral

b. ZnCl2 - Acidic

c. Ba(C2H3O2)2 - Basic

d. NH4I - Acidic

e. NaNO3 - Neutral

To determine whether a 0.5M solution of each salt is acidic, basic, or neutral, we need to analyze the nature of the ions present in the solution.

a. KCl: When KCl is dissolved in water, it dissociates into K+ and Cl- ions. Both K+ and Cl- are spectator ions and do not contribute to the acidity or basicity of the solution. Therefore, the solution is neutral.

b. ZnCl2: When ZnCl2 is dissolved in water, it dissociates into Zn2+ and 2Cl- ions. The presence of Zn2+ ions in the solution can hydrolyze water molecules, resulting in the formation of H+ ions. Therefore, the solution is acidic.

c. Ba(C2H3O2)2: When Ba(C2H3O2)2 is dissolved in water, it dissociates into Ba2+ and 2C2H3O2- ions. The acetate ions (C2H3O2-) can hydrolyze water, leading to the formation of OH- ions. Therefore, the solution is basic.

d. NH4I: When NH4I is dissolved in water, it dissociates into NH4+ and I- ions. The presence of NH4+ ions in the solution can undergo a weak hydrolysis, resulting in the formation of H+ ions. Therefore, the solution is acidic.

e. NaNO3: When NaNO3 is dissolved in water, it dissociates into Na+ and NO3- ions. Both Na+ and NO3- ions are spectator ions and do not contribute to the acidity or basicity of the solution. Therefore, the solution is neutral.

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Answer:

Collecting data

Explanation:

Scientific inquiry can be explained as methods undertook by scientists to profer solutions, explanations, predict natural occurence and to some extent solve some of the problems of the earth through scientific study and processes. Evidence of solutions is made available to be built upon by also other scientists in the near future.

process of scientific inquiry include, in no particular order:

Note, that the explanation below doesn't follow any order.

1. Formulating questions: This is the problem that needed to be solved. Scientific inquiries usually begin with a question that can be proven scientifically.

2. Observation: taking neccessary information for the experiment.  Collecting data (answer to the question) falls under this process as information collected are used to carry out the experiment.

3. Hypothesis: Based on the observation and test carried out, scientists provide answers to the experiment, however methods used remain open for further experiments by other scientists. This is done so the results are tested and proven before they can be generally accepted as a rule or law.

4. Experiment: the experiment is carried out here.

5. Data analysis: Here the data collected are analysed using scientific methods.

6. Results: This stage shows the other aforementioned stages took place. Results of the scientific research/experiment are published.

Answer:collecting data

Explanation:i did it on study island

Answer:

You're answer is correct. The third answer is correct.

Explanation:

Producers have the most energy, since they gain energy directly from the sun. Their energy is then passed up this upside down pyramid, which the energy is decreased by about 10% each time.

#teamtrees #WAP (Water And Plant)

Answer:

Explanation:

Limiting is HCl and excess is Ca(OH)2

excess is 296 grams Ca(OH)2

2 moles H2O will be formed

At equilibrium, the number of moles of \(Cl_2\) (g) will be 0.2025 mol.

1: Write the balanced chemical equation:

\(C_O\)(g) + \(Cl_2\)(g) ⟶ \(C_OCl_2\)(g)

2: Set up an ICE table to track the changes in moles of the substances involved in the reaction.

Initial:

\(C_O\)(g) = 0.3500 mol

\(Cl_2\)(g) = 0.05500 mol

\(C_OCl_2\)(g) = 0 mol

Change:

\(C_O\)(g) = -x

\(Cl_2\)(g) = -x

\(C_OCl_2\)(g) = +x

Equilibrium:

\(C_O\)(g) = 0.3500 - x mol

\(Cl_2\)(g) = 0.05500 - x mol

\(C_OCl_2\)(g) = x mol

3: Write the expression for the equilibrium constant (Kc) using the concentrations of the species involved:

Kc = [\(C_OCl_2\)(g)] / [\(C_O\)(g)] * [\(Cl_2\)(g)]

4: Substitute the given equilibrium constant (Kc) value into the expression:

1.2 x \(10^3\) = x / (0.3500 - x) * (0.05500 - x)

5: Solve the equation for x. Rearrange the equation to obtain a quadratic equation:

1.2 x \(10^3\) * (0.3500 - x) * (0.05500 - x) = x

6: Simplify and solve the quadratic equation. This can be done by multiplying out the terms, rearranging the equation to standard quadratic form, and then using the quadratic formula.

7: After solving the quadratic equation, you will find two possible values for x. However, since the number of moles cannot be negative, we discard the negative solution.

8: The positive value of x represents the number of moles of \(Cl_2\)(g) at equilibrium. Substitute the value of x into the expression for \(Cl_2\)(g):

\(Cl_2\)(g) = 0.05500 - x

9: Calculate the value of \(Cl_2\)(g) at equilibrium:

\(Cl_2\)(g) = 0.05500 - x

\(Cl_2\)(g) = 0.05500 - (positive value of x)

10: Calculate the final value of \(Cl_2\) (g) at equilibrium to get the answer.

Therefore, at equilibrium, the number of moles of \(Cl_2\) (g) will be 0.2025 mol.

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Answer:

1 - NO2 at 339 K

2 - Ne at 371 K

3 - H2 at 371 K

4 - H2 at 425 K

Explanation:

Kinetic Energy is directly related to temperature; the higher the temperature the higher the kinetic energy. Kinetic energy is also equal to 12m⋅v2, so if we want a high velocity we want high temp and low mass. So let's list out approximate masses:

m(H2)≈2

m(NO2)≈46

m(Ne)≈20

So we have NO2 at 339 K, the lowest temperature out of the mix, and the highest mass out of the mix, so this is moving the slowest.

In contrast, we have H2 at 425 K, the highest temperature out of the mix, and the lowest mass out of the mix, so this is moving the fastest.

Now we have Ne and H2 at 371 K, since they are at the same temperature they have the same kinetic energy. But H2 is lighter than Ne so it must be faster. To quantify this mathematically, let's assume (this is wrong but just as an assumption for an example) KE at 371 K is 100:

100=12⋅m⋅v2

200=m⋅v2

√200m=v

So H2 is about v=10 and Ne is about v=√10≈3

So the order to recap is:

1 - NO2 at 339 K

2 - Ne at 371 K

3 - H2 at 371 K

4 - H2 at 425 K

Hope that makes it clearer!

Answer: The nuclear equation is \(^{180}_{173}Tl \rightarrow ^{180}_{173}Tl + ^{0}_{0}\gamma\).

Explanation:

A nuclear reaction in which a heavy particle splits into another particle along with release of energy is called a nuclear fission reaction.

For example, \(^{180}_{173}Tl \rightarrow ^{180}_{173}Tl + ^{0}_{0}\gamma\)

Here, energy is radiated in the form of gamma radiation.

Thus, we can conclude that the nuclear equation is \(^{180}_{173}Tl \rightarrow ^{180}_{173}Tl + ^{0}_{0}\gamma\).

Answer:

To calculate the number of moles of copper, we first need to determine the mass of copper present in the sample:

Mass of copper = 159 g (mass of copper(II) oxide) - 127 g (mass of copper)

Mass of copper = 32 g

Now, we can use the molar mass of copper to calculate the number of moles:

Molar mass of copper = 63.55 g/mol

Number of moles of copper = mass of copper / molar mass of copper

Number of moles of copper = 32 g / 63.55 g/mol

Number of moles of copper = 0.504 mol

Therefore, there are 0.504 moles of copper in the sample.

Explanation:

Answer: The correct option is C (One of the fatty acid salts was unsaturated, and it completely isomerized under the reaction conditions).

Explanation:

Fats and oils belongs to a general group of compounds known as lipids. Fatty acids are weak acid and are divided into two:

--> Saturated fatty acids: These have NO double bonds in their hydrocarbon chain, and

--> Unsaturated fatty acids: These have one or more double bonds in their hydrocarbon chain.

SAPONIFICATION is defined as the process by which fats and oil is hydrolyzed with caustic alkali to yield propane-1,2,3-triol and the corresponding sodium salt of the component fatty acids. During this process, One hydroxide ion is required to hydrolyze one ester linkage of a triacylglycerol molecule. Because there are three ester linkages in a triacylglycerol, three equivalents of sodium hydroxide will be needed to completely saponify the triacylglycerol. This explains the reason why saponification of the triacylglycerol iresulted in four different fatty acid salts.

Answer:

Ultraviolet

Explanation:

It doesn't use much energy and so it creates ultraviolet light.

this is true, wind energy is a renewable natural resource c:

Answer:

amu

Explanation:

Please mark as brainleist

The atomic mass of a single atom is simply its total mass and is typically expressed in AMU

Answer:

C. average transnational kinetic energy of the particles in an object.

Explanation:

Answer:

highest concentration

C. 10M hcl

Answer:

THERE IS NO  such compound

Explanation:

Answer:

7.) 126.7 cm³

8.) 789 g

Explanation:

7.) To find the volume (cm³) of alcohol, you need to multiply the given mass (g) by the density. The denisty ratio represents grams of the alcohol per every 1 cm³. It is important to arrange the ratio in a way that allows for the cancellation of units (grams should be in the denominator). The final answer should have 4 sig figs to match the given value with the least amount of sig figs (100.0 grams).

 100.0 grams                  1 cm³
---------------------  x  ---------------------------  =  126.7 cm³
                                0.78945 grams

8.) This time, you are given the volume instead of the mass. The same process can be used in this problem, but you first need to convert liters (L) to cm³ to be able to use the denisty ratio. Once you find the volume in cm³, you can multiply it by the density to find the mass. Again, be sure to arrange the conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to match the given value with the least amount of sig figs (1.00 L).

1 L = 1,000 cm³

  1.00 L           1,000 cm³           0.78945 g
-------------  x  -------------------  x  --------------------  =  789 g
                             1 L                     1 cm³

Answer:

B. Geological Events and Lifeforms

Explanation:

The Earth's Geological time scale is mostly based on Geological Events and Lifeforms.

The Geological time scale provides a division of events on the earth into several time frames.

Each of the time units are based on events through the Earth's history and evolution of life.

The events are often recorded in rock strata and also as fossils which are the preserved remains of organisms.

The empirical formula of this compound is \(Fe_2O_3\)

To calculate the empirical formula of a compound, the value of moles of each element is needed.

As we have the information of the mass value, we will use the molar mass expression, which corresponds to:

\(MM_O = 16g/mol\\MM_Fe = 55.8g/mol\)

                                              \(MM = \frac{m}{mol}\)

                                                   \(16 = \frac{4.8}{x}\)

                                                   \(x = 0.3mol\)

                                                    \(55.8=\frac{11.2}{x}\\x = 0.2\)

As the value of the empirical formula must be an integer, simply multiply the two values ​​by a common factor:

                                                \(O = 0.3 \times 10 = 3\\Fe = 0.2 \times 10 = 2\)

                                                       \(Fe_2O_3\)

So, the empirical formula of this compound is \(Fe_2O_3\).

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Convex lenses refract light inward toward a focal point. Light rays progress through the edges of a convex lens and are bent most.

convex lenses are across in the middle. Rays of light that pass through the lens are conducted closer together (they converge). A convex lens is a meet lens. When parallel rays of light pass through a convex lens the refracted rays cross at one point called the principal focus.

. A convex lens is a connecting lens. When parallel rays of light pass through a convex lens the refracted rays merge at one point called the principal focus.

So we can conclude that Convex Lens. Concave Lens; It is known as a converging lens as light rays, when passed through this lens, tends to bend towards each other. It is known as a Convex Lens

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The statement is correct. The photoelectric effect refers to the phenomenon where electrons are ejected from the surface of a material when it is exposed to light. The frequency of light striking an electron in a metal must be above the threshold frequency in order for the photoelectric effect to occur.

The statement is correct. The photoelectric effect refers to the phenomenon where electrons are ejected from the surface of a material when it is exposed to light. However, for the photoelectric effect to occur, the frequency of the incident light must be above a certain threshold frequency.

The threshold frequency is the minimum frequency of light required to dislodge electrons from the material. Below this threshold frequency, regardless of the intensity or duration of the light, no electrons will be emitted.

This behavior can be explained by the particle-like nature of light, where light is composed of discrete packets of energy called photons. The energy of a photon is directly proportional to its frequency. Only photons with energy greater than or equal to the binding energy of the electrons in the material can dislodge them.

Therefore, the frequency of light striking an electron in a metal must be above the threshold frequency in order for the photoelectric effect to occur.

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Answer:

x-2 = 0

x = 2

hope this was help full

Answer:

See explanation

Explanation:

The first step in this reaction is a unimolecular reaction. It involves the formation of the carbocation. This is so because tertiary alkyl halides only undergo substitution by SN1 mechanism due to sterric crowding.

The second step in the reaction is bi molecular. In this step, the carbocation now combines with the OH^- to yield the alcohol.

Net equation of the reaction is;

(CH3)3CBr + OH^- -------> (CH3)3COH + Br^-

The intermediate here is the carbocation,  (CH3)3C^+

It is the 4th scenario is the dependent event. There are 7 gold tokens and 4 silver tokens in a cup. The first student randomly draws a gold token and keeps it. A second student randomly draws a gold token from the cup.

The fouth scenario is a dependent event because the probability of the second student drawing a gold token is affected by the outcome of the first student's draw.

If the first student draws a gold token, then there are only 6 gold tokens left in the cup, the probability changes. but  if the first student does not draw a gold token, then there are 7 gold tokens left in the cup, the probability will remain the same

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The amount of heat energy produced when 1 g of hydrogen and 2 g of nitrogen are reacted, is -6.61 KJ

First, we shall obtain the limiting reactant. Details below:

3H₂ + N₂ -> 2NH₃

From the balanced equation above,

28 g of N₂ reacted with 6 g of H₂

Therefore,

2 g of N₂ will react with = (2 × 6) / 28 = 0.43 g of H₂

We can see that only 0.43 g of H₂ is needed in the reaction.

Thus, the limiting reactant is N₂

Finally, we the amount of heat energy produced. Details below:

3H₂ + N₂ -> 2NH₃ ΔH = -92.6 KJ

From the balanced equation above,

When 28 grams of N₂ reacted, -92.6 KJ of heat energy were produced.

Therefore,

When 2 grams of N₂ will react to produce = (2 × -92.6) / 28 = -6.61 KJ

Thus the heat energy produced from the reaction is -6.61 KJ

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To calculate the moles of H+ and OH-, you need to know the concentration of the solution in terms of its pH or pOH value.

When you get the pH of the solution, you can use this formula to calculate the concentration of H+ ions: [H+] = 10^(-pH)

Also, if you know the pOH of the solution, you can use this formula to calculate the concentration of OH- ions: [OH-] = 10^(-pOH)

Having determined the concentration of H+ and OH- ions, the molarity formula can be used to calculate the number of moles of each ion as follows: moles = concentration (in mol/L) x volume (in L)

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