a radioactive sample has a half-life of 10 min. what fraction of the sample is left after 40 min? group of answer choices 1/4 1/2 1/8 1/16

the number-average and weight-average molar masses for each are 47273 g/mol and 78872 g/mol.

To calculate the number-average and weight-average molar masses of each mixture, we need to use the following formulas:

Number-average molar mass (Mn) = (ΣNiMi) / ΣNi

Weight-average molar mass (Mw) = (ΣWiMi) / ΣWi

where Ni and Wi are the number and weight fractions of each component i, and Mi is the molar mass of component i.

(a) For the first mixture, where equal numbers of molecules of each sample were mixed, the number and weight fractions of each component are 1/3. The number-average molar mass is:

\(Mn = (\frac{1}{3} *10000) + (\frac{1}{3} * 30000)+(\frac{1}{3} *100000)= 46667g/mol.\)

The weight-average molar mass is:


The number-average molar mass represents the average molar mass of the polymer chains in terms of their numbers, while the weight-average molar mass takes into account the relative abundance of each molar mass in terms of their weight. In this case, since the three samples have equal number and weight fractions, the number-average and weight-average molar masses are very close.

(b) For the second mixture, where equal masses of each sample were mixed, the number and weight fractions of each component are different due to their different molar masses. The number fraction of each component can be calculated as follows:

n1 = m1/M1 = 1/3
n2 = m2/M2 = 1/3
n3 = m3/M3 = 1/3

where mi is the mass of component i and Mi is the molar mass of component i.

The weight fraction of each component can be calculated as follows:

w1 = n1M1 / (n1M1 + n2M2 + n3M3) = 0.186
w2 = n2M2 / (n1M1+ n 2M2 + n3M3) = 0.294
w3 = n3M3 / (n1M1 + n2M2 + n3M3) = 0.520

where we have used the fact that the total mass of the mixture is the sum of the masses of each component, i.e. m1 + m2 + m3 = 1.

\(Me= (\frac{1}{3} *10000*10000)+(\frac{1}{3} *30000*30000)+(\frac{1}{3} *100000*100000)/ (\frac{1}{3} *10000) + (\frac{1}{3} * 30000)+(\frac{1}{3} *100000)= 47273 g/mol.\)

Using these fractions, we can calculate the number-average and weight-average molar masses of the mixture:
\(Mn = (\frac{1}{3} *10000) + (\frac{1}{3} * 30000)+(\frac{1}{3} *100000)= 46667g/mol.\)

Molecular weight= \((0.186 x 10,000 x 10,000) + (0.294 x 30,000 x 30,000) + (0.520 x 100,000 x 100,000) / (0.186 x 10,000) + (0.294 x 30,000) + (0.520 x 100,000) = 78,872 g mol-1\)


In this case, the weight-average molar mass is significantly higher than the number-average molar mass. This indicates that the higher molar mass component (100,000 g mol-1) is contributing more to the weight of the mixture, while the lower molar mass components (10,000 and 30,000 g mol-1) are contributing more to the number of polymer chains
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Answer:Atomic radius gets bigger

Explanation:

Atomic radius bigger because not only do the atoms have more and more protons and neutrons, and thus more mass in general, there is also stronger shielding affect. Shielding affect is when electrons closer to the nucleus block the positive charge from reaching electrons farther from the nucleus, and thus those far electrons are not drawn towards the nucleus as strongly, and spread out more, increasing atomic radius.

Hyperventilation, with a resulting decrease in \(PaCO_2\), is an expected compensatory reaction to the acid-base disorder of metabolic acidosis.

Metabolic acidosis is a condition characterized by a decrease in blood pH and bicarbonate levels, which can occur due to various causes such as diabetic ketoacidosis, lactic acidosis, renal failure, and ingestion of certain toxins. In response to this acidosis, the body tries to compensate by increasing respiration, resulting in hyperventilation.

Hyperventilation helps to decrease the concentration of carbon dioxide (\(CO_2\)) in the blood, which is an acid. By breathing rapidly and deeply, more \(CO_2\) is expelled from the body, which helps to restore the acid-base balance and increase the pH of the blood towards a normal level. This is known as respiratory compensation for metabolic acidosis.

However, it is important to note that hyperventilation can also lead to respiratory alkalosis if it continues for a prolonged period of time, resulting in a decrease in \(PaCO_2\) below normal levels. Therefore, careful monitoring and management of acid-base disorders is necessary to ensure appropriate compensation and avoid potential complications.

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The concentrations for the second, third, and fourth dilutions would be 0.3M, 0.03M, and 0.003M, respectively.

In a serial dilution, a concentrated solution is successively diluted to obtain solutions with lower concentrations. In this case, starting with a 30M sucrose solution, a series of four 1/10 dilutions are performed. The first dilution involves making 100 mL of the 1/10 dilution. To answer question 20, the calculation for the first dilution needs to be shown. For question 21, a diagram of the serial dilution with labeled volumes and concentrations of the stock and dilution beakers needs to be drawn. Finally, for question 22, the concentration calculations for each dilution step need to be provided.

To calculate the first dilution, we need to determine the concentration of the resulting solution. Since it is a 1/10 dilution, the concentration would be 1/10 times the original concentration. Therefore, the concentration of the first dilution would be 30M / 10 = 3M.

For question 21, a diagram needs to be drawn to illustrate the serial dilution process. The diagram should include the stock solution with a volume of 30M, the first dilution beaker with a volume of 100 mL and a concentration of 3M, and labels indicating the volumes and concentrations at each step of the dilution process.

For question 22, the concentration calculations for each dilution step need to be provided. Starting with the first dilution at 3M, subsequent dilutions would be 1/10 of the previous concentration. Therefore, the concentrations for the second, third, and fourth dilutions would be 0.3M, 0.03M, and 0.003M, respectively.

Overall, these calculations and the diagram represent the process and concentrations involved in the serial dilution of the 30M sucrose solution.


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No idea what this is for, but I hope you have an amazing day:)

A redox reaction is a chemical reaction in which one or more of the reacting species undergoes oxidation and one or more undergoes reduction. An oxidizing agent is an element or compound that oxidizes another substance, while a reducing agent is an element or compound that reduces another substance.

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The conversion of solar energy into the chemical energy of a carbohydrate occurs during the process of photosynthesis.

Certain organisms convert solar energy (sunlight) into chemical energy through photosynthesis, which is then used to construct carbohydrate molecules. When an organism breaks down food, the energy that was used to keep these molecules together is released.

The energy generated by photosynthesis continuously enters the planet's ecosystems and is transferred from one organism to another. As a result, the majority of the energy that all living things on Earth require comes from the process of photosynthesis, either directly or indirectly.

Oxygen is also released into the atmosphere as a result of photosynthesis. To summarize, humans rely almost entirely on photosynthesis-producing organisms for food and oxygen.

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The appearance and observable qualities of matter are considered to be its physical attributes. Colour, smell, taste, solubility, etc. An attribute that appears during a chemical reaction is known as a chemical property. A few examples include pH, reactivity, and flammability, etc. The correct option is B.

The chemical makeup or content of matter are not altered after a physical transformation.  The internal makeup is unaffected as molecules rearrange themselves during this transformation. The chemical attribute is unaffected by a physical change.

Here both crushing a mineral into powder and picking up a paper clip with a magnet are physical changes.

Thus the correct option is B.

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Answer:

they causes climate change by trapping heat and also they contribute to respiratory diseases from smog and air pollution

Answer:

They add C02 to our atmosphere which can give plants and soils more CO2. It can also make our earths temperature change a ton!

Explanation:

Greenhouse gases produce an increase in the average surface temperature of the earth over time.

Answer:

Lattice energy is an estimate of the bond strength.

Answer:

It is either B or D, and I believe the answer is D.

Explanation:

Deepwater drilling relies on mud being pumped into the drill well for pressure purposes. Without the mud, gas and oil would just rise up uncontrollably because without counteracting the pressure from the sea and the rock, it would be spewing out. The mud helps the drill create the heavy column of downward force needed to maintain control of the output of gas and oil.

The answer choices that would best match the description would be B or D. Since the mud is there for provide pressure and downward force, I would go with choice D as my answer.

Answer:

First convert ethene into C2H5Br by adding HBr. Then add aqueous KOH to form C2H5OH. Oxidize it by dilute H2SO4 and K2Cr2O7 to form CH3COOH. Add SOCl2 to form CH3COCl and reduction with Pd-baso4 and xylene.

Explanation:

I hope this helps you! :D

According to the analytical paper available in e-learning, there are 4 fatty acids found in soybean oil in significant quantities. The correct option is B.

These fatty acids are:

1. Linoleic acid (Omega-6): Linoleic acid is a polyunsaturated fatty acid and is essential for human health as it cannot be synthesized by the body. It plays a vital role in maintaining cell membranes, supporting the immune system, and providing energy.

2. Oleic acid (Omega-9): Oleic acid is a monounsaturated fatty acid that is beneficial for cardiovascular health. It helps to reduce LDL (bad) cholesterol levels while maintaining or increasing HDL (good) cholesterol levels.

3. Palmitic acid: Palmitic acid is a saturated fatty acid that is a common component in various plant oils. While saturated fats are generally considered less healthy, palmitic acid can still be part of a balanced diet.

4. Stearic acid: Stearic acid is another saturated fatty acid that is commonly found in plant oils. It has a neutral effect on blood cholesterol levels and can be safely consumed in moderation.

In conclusion, soybean oil contains 4 fatty acids in significant quantities. These fatty acids contribute to the overall nutritional profile of soybean oil and have various health benefits when consumed as part of a balanced diet.

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Answer:

They are stable

Explanation:

majority are stable

Answer:

0.1 and 0.2.

Explanation:

The person's blood is 0.1 decreases and become more acidic if it has a pH of 7.3 compared to its preferred 7.4 while on the other hand, the person's blood is 0.2 increases and become more alkaline it has a pH of 7.6rather than its preferred 7.4. There is 0.1 decrease and 0.2 increase in the pH of the person's blood. If the pH decreases so it means it moves towards more acidic whereas, if the pH increases there is moves towards alkaline.

The characteristics of the graphs we can find the answer on how to draw the graph

The graphical representation is one of the best methods to visualize the relationships between a series of experimental data and to be able to find their functional relationships.

A graphic representation has several parts

The scales are found with the relationship between the variation of the data between the amount of paper or graph range, let's look for the scales for each axis.

x-axis

The variation of the data  Δx = Final value - initial value

Paper range, generally it is  x = 20cm (sheet size)

They indicate that the graph must start at zero, so the minimum value must be changed,

             initial value = 0

              Δx = 760 -0 = 760

             x scale  = 760/20

             x scale  = 38 mb / cm of paper

y-axis

Data range   Δy= 0.9 -0

Paper range  y= 20 cm (sheet size)

            y-scale  = 0.9 / 20

            y scale  = 0.045 mL / cm paper

One of the characteristics of the scale is that it must be comfortable for graphing, which is why it approximates the following units

Selected scales  

         x scale  = 40 mb / cm paper

         y scale = 0.05 mL / cm paper

The second part consists of marking values ​​equally spaced and facilitating readable in the two axes, see attached for a graph made in a computer program

Plot each experimental point as best as possible, there are always some approximations by the selected scales

Draw a curve that passes through most of the experimental points and those that remain outside are balanced above and below the curve, in this case the program draws a line between each point, but it is preferable to draw a smooth curve.

In conclusion with the characteristics of the graphs we can find the answer on how to draw the graph

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calcium sulfite decomposes when heated to form calcium oxide and sulfur dioxide. This involves a Decomposition Reaction. 192.19 gram of sulfur dioxide is produced from 3 moles of calcium sulfite.

Sulfite is the name given to the SO32− anion. So the reactant is composed of calcium cations, Ca 2+  and sulfite anions, SO 32−. Since calcium cations have a 2+ charge, and oxygen anions have a 2− charge, & calcium oxide will simply be

Ca2 + O2− ⇒ Ca2​O2 ⇒ Ca O

Sulphur dioxide is a covalent compound. it contains one sulphur atom. Sulphur has no prefix in the name of the compound two oxygen atoms  oxygen has a di- prefix in the name of the compound. Therefore, you can say that sulfur dioxide is SO2.

This gives Ca SO3 (s] → Ca O (s] +SO 2(g]↑.

sulfur dioxide is produced from 3 moles of calcium sulfite.

so,  3 mole of CaSO3 *  1 mole of SO2 / 1 mole of Ca SO3

      = 3 mole of SO2 = 192.19 grams of SO2

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Answer:

C₄H₁₂ + 7O₂ --> 4CO₂ + 6H₂O

Explanation:

Organic molecules react with O2 to create water and CO2 in combustion processes. C4H12 is an organic molecule that combines with O2 to create water and CO2 as shown in the reactions.

As a result, this is the sole reaction that obeys the general combustion equation.

The ratio of octene to oxygen is 1:12.

To determine the ratio of octene (C8H16) to oxygen (O2) in the given reaction, we need to examine the balanced chemical equation. However, the equation you provided does not seem to be balanced. The coefficients for each compound must be determined to achieve a balanced equation before we can calculate the desired ratio.

Assuming you meant the combustion reaction of octene, a balanced equation would be:

C8H16 + 12O2 → 8CO2 + 8H2O

From the balanced equation, we can see that for every 1 mole of octene (C8H16), we require 12 moles of oxygen (O2) to completely react.

This means that for every 1 mole of octene, we need 12 moles of oxygen to fully combust the octene and produce the corresponding amounts of carbon dioxide (CO2) and water (H2O) as shown in the balanced equation.

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The acronym "MAP" stands for Modified Atmospheric Packaging as it relates to food preservation. The correct option is B.

This method involves altering the composition of gases within a package to help preserve the food.

The air inside the package is replaced with a modified gas mixture that contains a lower level of oxygen and higher levels of carbon dioxide and/or nitrogen.

This helps to slow down the growth of microorganisms and reduce oxidation, which can cause spoilage and degradation.

This method is commonly used for packaging meat, poultry, seafood, fruits, and vegetables.

By using MAP, the shelf life of these foods can be extended while maintaining their quality and freshness.

It is a widely used method in the food industry, especially for perishable products that are intended for transportation or storage.

Therefore, the correct option is B, Modified Atmospheric Packaging relates to food preservation, the acronym "MAP".

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Answer:

Nature is important

Explanation:

The amount of kilojoules absorbed by the water can be calculated using the formula Q = m*C*ΔT, where Q is the energy absorbed, m is the mass of water (175 g), C is the specific heat capacity of water (4.184 J/g°C), and ΔT is the change in temperature (88°C - 15°C = 73°C). the water absorbed 53.45 kilojoules of energy as it was heated from 15 to 88 degrees Celsius.

First, convert the mass of water to kilograms: 175 g / 1000 = 0.175 kg
Next, convert the specific heat capacity of water from joules to kilojoules: 4.184 J/g°C / 1000 = 0.004184 kJ/g°C
Finally, calculate the energy absorbed by the water: Q = 0.175 kg * 0.004184 kJ/g°C * 73°C = 0.05345 kJ

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Answer: Ketone

Explanation:

ASTM E384-99 (2014) is a standard test method published by ASTM International  titled "Standard Test Method for Microindentation Hardness of Materials." This standard provides guidelines and procedures for measuring the microindentation hardness of various materials.

The microindentation hardness test is a widely used method to evaluate the hardness of materials at small scales. It involves applying a controlled force using a specialized indenter, typically a diamond or tungsten carbide, onto the surface of the material and measuring the resulting indentation size. The hardness value is determined based on the indentation size and the applied force.

American Society for Testing and Materials E384-99 (2014) specifies the, test procedures, and calculations necessary for conducting the microindentation hardness test. It provides guidelines for selecting the appropriate indenter, test load, and measurement parameters based on the material type and expected hardness range.

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Answer:

The container will have a pressure of 8 atm when the temperature is 50 degrees Celsius

Explanation:

To calculate this temperature, we need a gas law that relates temperature and pressure.

This is the Gay Lussac’s law and we know from it that temperature and pressure are directly related

Thus;

P1/T1 = P2/T2

From the question;

P1 = 4 atm

T1 = 25 degrees celsius

P2 = 8 atm

T2 = ?

Substituting these values, we have;

4/25 = 8/T2

4T2 = 8 * 25

4T2 = 200

T2 = 200/4

T2 = 50 degrees Celsius

The correlation coefficient is a number between zero and 1 and the answer is false

And that is because the correlation coefficient is a number between -1 and one. A positive correlation coefficient means that two variables are positively correlated or move in the same direction. Plus one means perfect like full correlation, zero means there is no correlation whatsoever.

And a negative correlation means that as one variable moves in a positive direction, the other moves in a negative direction, so that is negative correlation, And the correlation of -1 means perfect negative correlation.

The correlation coefficient is a statistical measure of the strength of the relationship between the relative movements of two variables. The values range between -1.0 and 1.0. A calculated number greater than 1.0 or less than -1.0 means that there was an error in the correlation measurement.

A correlation of -1.0 shows a perfect negative correlation, while a correlation of 1.0 shows a perfect positive correlation. A correlation of 0.0 shows no linear relationship between the movement of the two variables.

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Answer:

The oxygen and water in air react with the metal to form the hydrated oxide. The familiar red form of rust is (Fe2O3), but iron has other oxidation states, so it can form other colors of rust

Explanation: