A pan containing 40 grams of water was allowed to cool from a temperature of 91.0 °C. If the amount of heat released is 1,300 joules, what is the approximate final temperature of the water? 74 °C 78 °C 81 °C 83 °C

The time taken for 0.240 mole sample of radiuim to decay to 1.88×10¯³ mole is 79.8 days

We'll begin by calculating the number of half-lives that has elapsed.

Original amount (N₀) = 0.240 mole

Amount remaining (N) = 1.88×10¯³ mole

N = 1/2ⁿ × N₀

1.88×10¯³ = 1/2ⁿ × 0.240

Cross multiply

1.88×10¯³ × 2ⁿ = 0.240

Divide both side by 1.88×10¯³

2ⁿ = 0.240 / 1.88×10¯³

2ⁿ = 128

2ⁿ = 2⁷

Thus, 7 half-lives has elapsed

Number of half-lives (n) = 7

Half-life (t½) = 11.4 days

t = n × t½

t = 7 × 11.4

Therefore, the time taken for 0.240 mole sample of radiuim to decay to 1.88×10¯³ mole is 79.8 days

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The biological Oxygen demand of the lake is increased by 1.5 ton.

Discussion:

The reaction of methanol with Oxygen is as follows;

In the reaction above; Since Methanol, CH3OH and Oxygen, O2 have the same molar mass; 32.

Therefore we can say since;

2 moles of CH3OH requires 3 moles of O2.

Therefore, 1 ton of methanol will require 1.5 ton of oxygen.

The biological Oxygen demand of the water is therefore increased by 1.5 ton as this is the amount of Oxygen consumed by the ethanol.

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an ionic compound is made of two or more elements held by a strong electrostatic force. metal atoms lose electrons to become positive ions, and non metals gain electrons to become negative ions. ionic bonding occurs between metals and non metals

Answer:

the answer is B.

Explanation:

your welcome

Answer:

the answer is B

Explanation:

i have the same exact questionn

Answer:

The longer the path length, the more molecules there are in the path of the beam of radiation, therefore the absorbance goes up. As you likely know from other experiences, a particular chemical species absorbs some wavelengths of radiation and not others

The wavelength is used to determine the concentration of a colored solution since at this wavelength a slight change in concentration allows for a significant change in the absorbance of light.

Wavelength is the distance between equal points in adjacent cycles of a wave signal that propagates in space. Each wave has a definite shape and length, so  the distance between the peaks is called the wavelength.

It can be calculated by this formula-

[tex]\lambda=\frac{v}{f}[/tex]

[tex]where, \lambda =wavelength\\{v} = velocity\\{f} = frequency[/tex]

Absorbance measures the amount of light with a specific wavelength which a given substance prevents from passing through ii.

Thus, the wavelength is used to determine the concentration of a colored solution since at this wavelength a slight change in concentration allows for a significant change in the absorbance of light.

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From the dilution formula, we have that at constant value of the solute, the volume of the solution is inversely proportional to the concentration.

The correct responses are;

Reasons:

The given parameters are;

The concentration of the KCl solution = 4% m/v

Taking the solution as solution of KCl

The volume of the solution in container 1 = Two times less than the volume of KCl solution.

[tex]V_{container \, 1} = \displaystyle \mathbf{ \frac{1}{2} \cdot V_{4\% \, solution}}[/tex]

The volume of the solution in container 2 = Two times larger compared to the volume of KCl solution.

[tex]V_{container \, 2} = \mathbf{\displaystyle 2 \times V_{4\% \, solution}}[/tex]

The volume of the solution in container 3 = Two times larger than the container two solution volume.

[tex]V_{container \, 3} = \displaystyle \mathbf{ 2 \times V_{container \, 2}}[/tex]

Therefore;

[tex]V_{container \, 3} = \displaystyle 2 \times 2 \times V_{4\% \, solution} = \mathbf{4 \times V_{4\% \, solution }}[/tex]

Part A Required:

a. To select the container that represent the dilution of the 4% solution to 2%

Solution:

The dilution formula is; C₁·V₁ = C₂·V₂

Therefore;

[tex]\displaystyle V_1 = \mathbf{\frac{C_1 \cdot V_1}{C_2}}[/tex]

C₁ =4%, C₂ = 2%, we get;

[tex]\displaystyle V_1 = \frac{4 \cdot V_1}{2} = 2 \cdot V_1[/tex]

The volume of the container that represents a 2% dilution is container 2

which is filled with a solution of a volume two times larger compared to the

KCl solution.

Part B:

Required:

The container diluted to a 1% m/v KCl solution.

Solution;

Using the dilution formula, we have;

C₁ = 4%, C₂ = 1%

Therefore;

[tex]\displaystyle V_1 = \frac{C_1 \cdot V_1}{C_2}[/tex]

[tex]\displaystyle V_1 = \frac{4 \cdot V_1}{1} = \mathbf{4 \cdot V_1}[/tex]

The volume of the solution is four times the volume of the 4% KCl solution, which is equivalent to the volume in container 3.

Possible parts of the question are;

Select the container that represents the dilution of the 4% (m/v) KCl solution to obtain the solutions that follows;

Part A: a 2% (m/v) KCl solution

Part B: a solution that is a 1% (m/v) KCl solution

Please see attached drawings

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Answer:

C

Explanation:

The answer is C, because nitrogen is in purple, and oxygen is in blue, and in NO2 you have 2 oxygen atoms.

Answer:

The bleaching action of sulphur di oxide is temporary because it involves the process of reduction. sulphur di oxide removes oxygen from the coloured substance and makes it colourless. Atmospheric oxygen slowly takes place of the removed oxygen and because of which the material regains the co

Answer:

you lift my feet off the ground spin me around you make me crazier crazier

Answer:

The option where the atoms are furthest apart.

Explanation:

Gasses are the most energetic of the three basic states of matter, their atoms have more kinetic energy than either solids or liquids and will therefore also have the most spread out atoms.

Answer:

landslide mudflows slump and creep

Explanation:

no explanation

Answer:

Gas

Explanation:

Mechanical waves- travel faster in solids & slowest in gases

Electromagnetic waves- travel fastest in empty space and slowest in solids.

Because they are so close, than can collide very quickly, i.e. it takes less time for a molecule of the solid to 'bump' into its neighborough. Solids are packed together tighter than liquids and gases, hence sound travels fastest in solids. The distances in liquids are shorter than in gases, but longer than in solids.

Answer C- Gas

Explanation:

Electromagnetic waves- travel fastest in empty space and slowest in solids.

Yes according to reliable sources.

Answer:

la primera va con la última

oh so sad for ur msg

if i were science student then absolutely i will help

but i am। computer science student in management faculty so so sry

Explanation:

your answer to the chemistry question is given !

hope that helps you.

Answer:

11000 g/L

Explanation:

Since density is mass divided by volume, find the volume of the metal ball by subtracting the initial volume of water in the graduated cylinder from the ending volume. In this case, the volume would be 17.90 mL - 16.05 mL =  1.85 mL = 0.00185 L. Then using the formula for density, calculate 20.350 g / 0.00185 L = 11000 g/L.

Density is an intensive property as it does not depend on the quantity of the substances Whereas mass and volume are extensive property. Therefore, the density of the metal ball is 11000 g/L.

Density tells about the compactness of the substances, how much dense is the substances in other words. Object that is more denser than water they just sink in the water.

Mathematically,

Density = Mass of the metal ball ÷volume marked on the graduated cylinder

volume=ending volume- initial volume of water in the graduated cylinder            

            =17.90 mL - 16.05 mL

            =  1.85 mL

            = 0.00185 L.

substituting all the given values in the above equation, we get

density=  20.350 g / 0.00185 L

            = 11000 g/L.

Therefore, the density of the metal ball is 11000 g/L.

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Answer:

we heat up because the component with lower boiling evaporates first,

leaving the other behind

With regard to distilling the mixture of methanol and water using simple

distillation and fractional distillation, a statement that can be made that is

not true is that; Methanol and water form an azeotrope.

Reasons:

Azeotrope are liquid mixtures that have the property of a constant boiling

point due to the contents of the vapor are the same as the mixture.

Water when mixed with methanol form network structures. However,

methanol does not form a binary azeotrope with water.

Therefore, a statement that is not true is that methanol and water form an

azeotrope a mixture that has a constant boiling temperature.

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Fire extinguishment is referred to the stage in which flames are not visible

and the combustible item no longer generates heat.

This stage refers to when the fire has been put out through a fire

extinguisher or other compounds.   When fire is put out, there is no longer

flames present.

The absence of flames also means that there is no heat generation or

combustion products due to the absence of a heat source.

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Answer:

sound is given off

Explanation:

due to a number of scientific research sound that is given off of an object is not due to a chemical reaction.

Answer:

I believe they deserve to be here.

Explanation:

Answer: Hi! The partial pressure of CH4 is

=1 atm

Explanation:

The partial pressure of methane in the mixture of methane and ethane has been 1 atm.

Partial pressure has been the pressure exerted by a gas in the solution or mixture. The partial pressure of each gas has been the total pressure of the gaseous mixture.

The partial pressure of the gas has been dependent on the volume, temperature, and concentration of the gas.

The given methane has a partial pressure of 1 atm in the 15 L vessel. The addition of ethane results in the change in the total pressure of the mixture, as there have been additional moles of solute that contributes to the solution pressure.

However, since there has been no change in the concentration and volume of methane, the pressure exerted by methane has been the same. Thus, the partial pressure of methane has been 1 atm.

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Answer: 2

Explanation:

Ba(OH)2 contains two oxygen atoms

BaSO4 contains four oxygen atoms.

This means that barium sulfate contains two more oxygen atoms than barium hydroxide in its formula.

Hope this helps!! :)

According to formula BaSO₄, Barium sulfate contains 2 more oxygen atom.

The correct option is (A) 2

Ba(OH)₂ has two oxygen atoms in it.

Four oxygen atoms may be found in BaSO₄.

This indicates that the formula of barium sulfate has two extra oxygen atoms than the formula of barium hydroxide.

Barium sulfate, often known as BaSO4, is a transparent white pigment that has a long history. It is produced by combining sulfuric acid with barium hydroxide and other sources of barium.

Chemically speaking, barium hydroxide has the formula Ba(OH)2. The monohydrate of barium, sometimes referred to as baryta or baryta-water, is one of the element's main compounds. The typical commercial form of monohydrate is this white granular substance.

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Answer:

Explanation:

Firstly, let us calculate the molar mass of the glucose. To find the molar mass we need to add the masses of individual elements which constitute one glucose molecule.

Now, we know that

Molar mass of Carbon C=12gmol−1

Molar mass of Hydrogen H=1gmol−1

Molar mass of oxygen O=16gmol−1

Therefore, Molar Mass of glucose (C6H12O6) can be calculated as shown below

⇒ 6×12+12×1+6×16

⇒72+12+96⇒180gmol−1

Given mass of glucose = 300g

Now, we can calculate the number of moles in given mass of glucose, using the below formula,

Using the Formula numberofmoles=givenmassmolarmass we get

numberofmoles=300180 = 1.7 moles or 2 moles (approx.)

Hence the number of moles present in 300 g of glucose is 1.7 moles or 2 moles approximately.

Answer:

1. An independent variable is manipulated, or changed. The dependent, or responding variable, changes based on the independent variable. The dependent variable is examined.

2. It is a controlled experiment.

Explanation:

In a controlled experiment all variables are kept the same, except for the one being tested, which is called the experimental variable , or independent variable . This group is the experimental group . The group that is not affected by the experimental variable is the control group .

Very often a graph will be used to analyze the results of the experiment. The independent/experimental variable is placed on the x-axis and the dependent variable is placed on the y-axis. The dependent variable is what is measured as a result of the application of the experimental variable.

A variable that is independent is altered. Based on the independent variable, the responding variable, or dependent variable, alters. Examining the dependent variable. The experiment is carefully controlled.

In mathematical modeling, statistical modeling, and experimental sciences, there are dependent and independent variables. Dependent variables get their name because, during an experiment, their values are investigated under the presumption or requirement that they are dependent on the values of other variables due to some law or rule.

A variable that is independent is precisely what it sounds like. It is a stand-alone variable that is unaffected by the other variables you are attempting to assess. Age, for instance, could be an independent variable.

When doing an experiment, the independent variable is what you alter, and the dependent variable is what changes as a result of that change. This is an easy way to conceive of independent and dependent variables.

Thus, based on the independent variable, the responding variable, or dependent variable, alters.

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This is the answer i hope it helps

A sample of gas has Pi = 0.768 ATM, Vi = 10.5 L, and Ti = 300 K. What is the final pressure if VF = 7.85 L and T and f = 250 K?

Answer:

D. works with bones to help you move

Explanation:

Your muscles and tendons are what help bones move.

Some benefits of genetic engineering in agriculture are increased crop yields, reduced costs for food or drug production, reduced need for pesticides, enhanced nutrient composition and food quality, resistance to pests and disease, greater food security, and medical benefits to the world's growing population.

Insect resistance: Corn

Herbicide tolerance: Soybean

THE ADVANTAGE OF IODIN

THE DISADVANTAGE OF IODIN