A volumetric pipette has one marked line that indicates a specific volume. Considering polar substances dip downward in a glass volumetric pippette creating a concave meniscus, what is the correct way to read a volumetric pipette to have the most accurate measurement?.

Answer:

(b)  19.9 moles

Explanation:

To convert from moles Al to moles O₂, you need to multiply the given value by the mole-to-mole ratio of each component. This ratio is constructed via the coefficients in the balanced reaction. The desired unit (moles O₂) should be placed in the numerator to allow for the cancellation of units.

2 Al₂O₃ ----> 4 Al + 3 O₂
                    ^         ^            

26.5 moles Al           3 moles O₂
---------------------  x  ----------------------  =  19.9 moles O₂
                                 4 moles Al

16.06 cm is the height of the tetra bromoethane column in the barometer in cm.

A barometer is a scientific instrument used to measure atmospheric pressure, also called barometric pressure.

Explanation:

Pressure of the liquid column=ρgh

ρ= density of the liquid

h= height of the column

g= due to gravity

the

height of the mercury column corresponding to 0.971 atm

= 0.951×76÷1atm = 73.796 cm

[tex]\rho_1h_1g=\rho_2h_2g[/tex]

2.96 g/mL x 73.796 cm =13.6 g/mL [tex]h_2[/tex]

[tex]h_2[/tex]=16.06148235 =16.06 cm

16.06 cm is the height of the tetra bromoethane column in the barometer in cm.

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The process of  embryonic development is the process by which the fetus of an organism is developed.

The process of  embryonic development is the process by which the fetus of an organism is developed.

We know that all vertebrates are the same at the embryonic stage as shown in the image. Hence the following statements are true;

Missing parts

Based on these images, what can you conclude about the organisms?

1)They’re a mixture of vertebrates and invertebrates.

2)They have similarities in their embryonic stages that don’t exist in their adult forms.

3)They all undergo metamorphosis.

4)They all contain a backbone, or spinal column.

5)They’re the same species of organism.

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Answer:

The reaction absorbs energy ( + or exothermic)

Explanation:

When the temperature of a thermometer increases during a chemical reaction, then the reaction absorbs energy (+ or endothermic). Therefore, the correct option is B.

A rise in the temperature of a thermometer during a chemical reaction is a sign that the system is absorbing energy. This implies that the reaction is endothermic, meaning that energy must be supplied for it to proceed. Generally, endothermic reactions take heat from the environment and raise the temperature. Chemical bonds are broken and the process is accelerated by the absorbed energy.

Therefore, the correct option is B.

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Answer:

0

Explanation:

they cancel each other out (ex: 1 positive and 1 negative cancels, making it neutral or a charge of 0)

The earth's mantle will not change in the future because this region is safe from the intervention of human beings.

The transfer of heat and material in the mantle helps us to determine the landscape of Earth. Activity in the mantle moves the plate tectonics, that contributes to volcanoes, seafloor spreading, earthquakes, and building of mountains.

So we can conclude that the earth's mantle will not change in the future because this region is safe from the intervention of human beings.

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The structure of the compound, there will be ten unique signals in the carbon 13 NMR of the compound.

The NMR signals shows the atoms in a compound that are in unique chemical environments. The atoms that are in the same chemical environment will only give one signal.

Based on the structure of the compound, there will be ten unique signals in the carbon 13 NMR of the compound.

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Answer:

C

Explanation:

with combustion you must know that your products must be carbon dioxide and water. I think you copied your question incorrectly.

Answer: Are people happier if they have more spare time?

Explanation:

Happiness cannot be measured quantitatively.

Answer:

0.736

Explanation:

*I am not sure what you mean by "carbon tetrahedral". I'm assuming you are just referring to individual carbon.*

To find the mole percent, you need to (1) convert grams benzene and grams carbon to moles (via their molar masses) and then (2) calculate the mole fraction (via the mole fraction formula).

(Step 1)

Benzene = C₆H₆

Molar Mass (C₆H₆) = 6(12.01 g/mol) + 6(1.008 g/mol)

Molar Mass (C₆H₆) = 78.108 g/mol

70 g C₆H₆          1 mole
---------------  x  ------------------  =  0.896 mole C₆H₆
                         78.108 g

Molar Mass (C) = 12.01 g/mol

30 g C           1 mole
------------  x  -----------------  =  2.50 mole C
                       12.01 g

(Step 2)

                                           moles solute
Mole Fraction  =  ----------------------------------------------
                              moles solute + moles solvent

                                              2.50 mole C
Mole Fraction  =  -------------------------------------------------  =  0.736
                             (0.896 mole C₆H₆ + 2.50 mole C)

Answer:

An exergonic reaction releases free energy, and an endergonic reaction absorbs free energy.

Explanation:

hope it helps

The earth's mantle will not change in the future because this region is safe from the intervention of human beings.

The transfer of heat and material in the mantle helps us to determine the landscape of Earth. Activity in the mantle moves the plate tectonics, that contributes to volcanoes, seafloor spreading, earthquakes, and building of mountains.

So we can conclude that the earth's mantle will not change in the future because this region is safe from the intervention of human beings.

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Answer:

It's the first answer

Explanation:

Aqueous just means that the solution is just dissolved in water

Answer:

4 NH₃ (g) + 3 O₂ (g) ----> 2 N₂ (g) + 6 H₂O (g) + energy

Explanation:

The unbalanced equation:

NH₃ (g) + O₂ (g) ----> N₂ (g) + H₂O (g) + energy

Reactants: 1 nitrogen, 3 hydrogen, 2 oxygen

Products: 2 nitrogen, 2 hydrogen, 1 oxygen

The sort-of balanced equation

2 NH₃ (g) + 1/2 O₂ (g) ----> N₂ (g) + 3 H₂O (g) + energy

I first started by balancing the nitrogens. This then lead me to balance the hydrogens. When I went to balance the oxygens, only a 1/2 coefficient would work. However, 1/2 coefficients are technically incorrect. To get rid of this coefficient, you need to multiply each coefficient by 2.

The balanced equation:

4 NH₃ (g) + 3 O₂ (g) ----> 2 N₂ (g) + 6 H₂O (g) + energy

Reactants: 4 nitrogen, 12 hydrogen, 6 oxygen

Products: 4 nitrogen, 12 hydrogen, 6 oxygen

Now, all of the elements are equal on both sides and there are no 1/2 coefficients. These are the smallest whole-number coefficients because some of the numbers cannot be further simplified (3).

It is evident from the provided map that the African Ocean is enlarging at a divergent plate boundary. So, the correct option is B.

When two tectonic plates diverge from one another, the area is known as a diverging plate border. New crust forms on the plate margins when the plates divide and magma rises from the mantle to fill the space. The creation of mid-ocean ridges is a result of this process, known as seafloor spreading.

Divergent plate borders can also occur on land, and they can eventually result in the formation of new ocean basins by forming rift valleys. The spreading of the seabed is aided by the divergent limits in the middle of the ocean. A fracture occurs on the ocean floor as plates made of oceanic crust move apart from one another.  

Therefore, the correct option is B.

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Your question is incomplete, most probably the complete question is:

This map shows the age of the Atlantic’s oceanic crust. Which statement is supported by the information in the map?

A. The African continental plates are undergoing continental drift.

B. The African Ocean is growing wider at a divergent plate boundary.

C. The seafloor is shrinking along a convergent plate boundary.

D. The seafloor is undergoing subduction under the North America plate.

The given reaction Mg + O₂ → MgO is a type of Synthesis reaction. Hence option (1) is correct.

Synthesis reactions are reactions that occur when two different atoms or molecules interact to form one molecule or compound.

It is also known as combination reaction

In the given reaction Mg and O combines with each other to form one product i.e, MgO. Hence, The given reaction Mg + O₂ → MgO is a type of Synthesis reaction. Thus, option (1) is correct.

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The enthalpy of combustion of 1 mole of acetylene for the reaction using the information in the table (attached as figure) is - 1,256 kJ/mol

The enthalpy of combustion of a substance is defined as the heat energy given out when one mole of a substance burns completely in oxygen.

Hence, The enthalpy of combustion of 1 mole of acetylene for the reaction using the information in the table is - 1,256 kJ/mol

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Considering the Charles's law, the sample of carbon dioxide gas will occupy 308.72 mL.

Charles's law establishes the relationship between the temperature and the volume of a gas when the pressure is constant. This law says that the volume is directly proportional to the temperature of the gas: for a given sum of gas at constant pressure, as the temperature increases, the volume of the gas increases and as the temperature decreases, the volume of the gas decreases.

Mathematically, Charles's law states that the ratio between volume and temperature will always have the same value:

[tex]\frac{V}{T} =k[/tex]

Considering an initial state 1 and a final state 2, it is fulfilled:

[tex]\frac{V1}{T1} =\frac{V2}{T2}[/tex]

In this case, you know:

Replacing in Charles's law:

[tex]\frac{250 mL}{298 K} =\frac{V2}{368 K}[/tex]

Solving:

[tex]V2=368 K\frac{250 mL}{298 K}[/tex]

V2= 308.72 mL

Finally, the sample of carbon dioxide gas will occupy 308.72 mL.

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Answer:

310mL

Explanation:

A sample of carbon dioxide gas occupies a volume of 250 mL at 25°C. What volume will it occupy at 95°C?

Use the formula:

V1

T1

=

V2

T2

Temperature conversion: __°C + 273 K

Answer:

chemical reactions In our daily environment are

1) Cooking food

2) Photosynthesis

3) rusting

4) painting

5) respiration

6) combustion

7) Electrochemistry (including chemical batteries)

8)Digestion

9)Soap and detergent reactions

10)Acid-base reactions

11) fermentation

12) oxidation

13 ) burning of paper

14) riping of fruits

15) frying egg

16) souring of milk

17) baking

18) heating sugar

19) burning wood

20) rising bread

Answer:

Explanation:

The balanced equation for the decomposition of water is:

2H2O = 2H2 + 1O2

This tells us that we should expect 1 mole of O2 for every 2 moles of H2O, a molar ratio of (1 O2/2 H2O).

If we start with 2 moles of water, we should get (2mole H2O)*(1 O2/2 H2O) = 1 mole of H2.

But we are given just 20ml of water by the stingy boss.  We need to calculate the number of moles of water in that 20 ml.  We'll assume pure water at room temperature, so density = 1g/ml.  We have 20 g of H2O.  To find moles, divide by water's molar mass of 18 g/mole:

20g/(18g/mole) = 1.11 moles H2O

The moles of H2 produced would be:

(1.11 moles H2O)*(1 O2/2 H2O) = 0.55 moles O2 produced

We are not given the conditions of temperature and pressure, so the only way the calculate a volume of gas occupied by 1 mole of oxygen is to assume standard temperature and pressure (STP).  At STP 1 mole of gas occupies 22.4 liters.

1 mole of O2 will be 22.4 liters.

0.55 moles of O2 would be:

(0.55 mole O2)*(22.4 liters) = 12.32 liters

Answer: 3 methylhexane

Explanation: Attached is a picture of the molecule. Courtesy of the National Institute of Health, United States Government.

Answer: 3-methylhexane

Explanation:

The parent chain is six carbon atoms long, so there is the prefix 'hex'

There is a methyl branch on the third carbon atom, so it is 3-methylhexane.

Answer: Some possible bias in an experiment about how sleep affects mood could be a person's average mood with or without sleep, how people are acting in the experiment compared to how they actually would in their normal environment, or even how the person collected the data for the experiment interprets their moods.

Explanation:

1. A person's mood could be relatively different depending on other factors than just sleep, so it could affect experiment. For example if an emotional crisis had occurred recently, it could affect your mood and environmental factors could affected your mood, like weather.

2. A person could also change their mood around strangers or even when participating in the experiment. For instance if they aren't comfortable with the person taking down the analysist or the other test subjects, they make act differently than they usually do at home where they're comfortable.

3. A person collecting the data will have to know how to specify and determine a persons mood with their instruments. For example, if they're doing it just by talking with the test subjects, they'll have to know how to properly understand their different stages of each of their moods with out the data collectors mood changing as well. Also, if the data collectors mood is changed at all it can slightly affect the experiments results as well.

Considering the definition of molar mass, the moles of gas used are 10.625 moles.

The molar mass of substance is a property defined as its mass per unit quantity of substance, in other words, molar mass is the amount of mass that a substance contains in one mole.

Natural gas has a molar mass of 16.0 g/mole.

You started out the day with a tank containing 200.0 g of natural gas.  So, you can apply the following rule of three: If by definition of molar mass 16 grams are contained in 1 mole, 200 grams are contained in how many moles?

[tex]amount of moles at the beginning=\frac{200 gramsx1 mole}{16 grams}[/tex]

amount of moles at the beginning= 12.5 moles

At the end of the day, your tank contains 30.0 g of natural gas. So, you can apply the following rule of three: If by definition of molar mass 16 grams are contained in 1 mole, 30 grams are contained in how many moles?

[tex]amount of moles at the end=\frac{30 gramsx1 mole}{16 grams}[/tex]

amount of moles at the end= 1.875 moles

The number of moles used will be the difference between the number of moles used initially and the contents at the end of the day.

moles used= amount of moles at the beginning - amount of moles at the end

moles used= 12.5 moles - 1.875 moles

moles used= 10.625 moles

Finally, the moles of gas used are 10.625 moles.

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In the given heating curve, Particles of the substance have the most kinetic energy when the substance is (a) 1. A gas. The part of the graph that represents where the substance has the least amount of potential energy is labeled (b) 1. Solid.

The heating curve is the relationship between the heating system supply temperature and the outside air temperature.

Gas molecules have the highest average velocities among the three states of matter so gas has the highest kinetic energy.

During freezing, a substance loses a lot of potential energy so solid has the least potential energy.

Hence, In the given heating curve, Particles of the substance have the most kinetic energy when the substance is (a) 1. A gas.

The part of the graph that represents where the substance has the least amount of potential energy is labeled (b) 1. Solid.

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Answer:

Explanation:The ratio of Coulomb force to gravitational force for an electron and a proton is given as,

r

1

​

=

R

2

Gm

1

​

m

2

​

​

4πε

0

​

1

​

×

R

2

q

1

​

q

2

​

​

​

=

6.67×10

−11

×9.1×10

−31

×1.67×10

−27

9×10

9

×(1.6×10

−19

)×(1.6×10

−19

)

​

=

1

2.27×10

39

​

The ratio of Coulomb force to gravitational force for two protons is given as,

r

2

​

=

R

2

Gm

2

​

4πε

0

​

1

​

×

R

2

q

1

​

q

2

​

​

​

=

6.67×10

−11

×(1.67×10

−27

)

2

9×10

9

×(1.6×10

−19

)×(1.6×10

−19

)

​

=

1

1.24×10

36

​

(b)

The magnitude of Coulomb force between electron and proton is given as,

F=

4πε

0

​

1

​

×

R

2

q

1

​

q

2

​

​

=

(10

−10

)

2

9×10

9

×(1.6×10

−19

)×(1.6×10

−19

)

​

=2.304×10

−8

N

The acceleration of electron is given as,

a

1

​

=

m

1

​

F

​

=

9.1×10

−31

2.304×10

−8

​

=2.5×10

22

m/s

2

The acceleration of proton is given as,

a

2

​

=

m

2

​

F

​

=

1.67×10

−27

2.304×10

−8

​

=1.4×10

19

m/s

2

Answer:

glucose is in large sugar molecules, while fructose is in simple fruits and vegetables

glucose breaks down disaccharides or polysaccharides with large sugar molecules and fructose is found in fruits and veggies like corn, mangos, and apples. they are both carbs.

[tex]\quad \huge \quad \quad \boxed{ \tt \:Answer }[/tex]

[tex]\qquad \tt \rightarrow \:2.8 × {10}^{-5}[/tex]

____________________________________

[tex] \large \tt Solution \: : [/tex]

[tex]\qquad \tt \rightarrow \: \dfrac{2.36 \times 10 {}^{ - 2} }{8.4 \times {10}^{2} } [/tex]

[tex]\qquad \tt \rightarrow \: \dfrac{2.36 }{8.4 } \times \cfrac{10 {}^{ - 2} }{10 {}^{2} } [/tex]

[tex]\qquad \tt \rightarrow \: 0.28 \times 10 {}^{ - 2 - 2} [/tex]

[tex]\qquad \tt \rightarrow \: 0.28 \times 10 {}^{ - 4} [/tex]

[tex]\qquad \tt \rightarrow \: 2.8 \times 10 {}^{ - 5} [/tex]

Answered by : ❝ AǫᴜᴀWɪᴢ ❞

Number 2 represents this process on the hydrologic cycle diagram. Therefore, the correct option is option B.

One of the most significant natural processes is the hydrologic cycle, which we may often take for granted. This process causes the water in the entire earth to change forms, locations, or accessibility.

Water transitions between three distinct forms during this cycle, to put it simply. It can be found in many states of liquid, gas, or solid, including ice, steam, and water. Water will frequently transition between these three states throughout the cycle: freezing into ice, melting into water, evaporating becoming water vapor, but finally condensing back into water. Number 2 represents this process on the hydrologic cycle diagram.

Therefore, the correct option is option B.

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The vapour pressure in the water flask is 23.686 torr.

The pressure of [tex]H_2[/tex] in the flask was 713.514  torr.

Pressure is the [tex]H_2[/tex] exerting in the flask is 688.314 torr

Vapour pressure is a measure of the tendency of a material to change into the gaseous or vapour state, and it increases with temperature.

a.The vapour pressure of water is given by:

[tex]Log_{10} P =A- \frac{B}{C+T}[/tex], where T is in degree Celcius, P is in torr.

For 0-100 degree celcius, A=8.07131, B=1730.63, C=233.426

[tex]Log_{10} P = 8.07131 - \frac{1730.63}{233.426+25} =1.3745[/tex]

As T =25 degree celcius

[tex]P = 10^{1.3745} torr[/tex] =23.686 torr

b.We know that [tex]P_{total} =P_{H_2} + P_{H_2O}[/tex]

[tex]P_{total}[/tex] = Atmospheric pressure

[tex]737.2 torr = P_{H_2} +23.686 torr[/tex]

[tex]P_{H_2} = 713.514 torr[/tex]

c.After there is a leak in the gas collection tube, the amount at pressure due to water vapour remains unchanged as it is a quantity dependent on temperature.

[tex]P_{total} =P_{H_2} + P_{H_2O} + P_{leaking \;air}[/tex]

[tex]737.2 torr = P_{H_2} + 23.686 torr + 25.2 torr[/tex]

[tex]P_{H_2} =688.314 torr[/tex]

For calculating molar mass of any gas:

M= Density X (RT ÷ P)

M= 0.714 g X ([tex]8.314 J mol^{-1}K^{-1}[/tex]273 K ÷ 101325 Pa)

M= 15.994 g/mol = 16 g/mol.

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