why does stirring increase the speed of a solute dissolving in water

Answer:

Explanation:

The total energy or intrinsic energy of a system is called the enthalpy. In thermochemistry, we have two types of enthalpy changes which are:

For the freezing of water, the enthalpy change is an exothermic one. Exothermic changes are designated as negative. In this chemical change, heat is liberated to the surroundings and this leaves the environment at a much higher temperature. In freezing, the enviroment gains more heat as the material begins to cool to lower temperature.

Entropy is the degree of randomness or disorderliness of a system. When a phase change occurs from liquid to solid, freezing takes place. Such a change increases the orderliness of a system and entropy diminishes. Here, entropy is negative.

The free energy is a measure of the energy a system that does useful work. Free energy depends on enthalpy, entropy and temperature of a system. For phase changes such as freezing of water, the value of free energy change is 0.

For this process, an increases in temperature makes it non-spontaneous. Increasing temperature would alter the course of the reaction and makes it exothermic. For entropy, increasing temperature would increase entropy and therefore, the reaction would not be feasible.

Temperature would mostly affect the free energy. An increase in temperature would increase the value of entropy change and the reaction would not be spontaneous. With falling temperature value, the reaction becomes more spontaneous and favored.

Answer:

=2.7 g/cm³

=2700 kg/m³

Explanation:

Density is a ratio of the mass of an object to its volume.

The volume of the named block of aluminium is calculated as follows:

90mL - 75mL= 15mL

15mL = 15 cm³

The mass = 40.5 g

Therefore ρ=m/v

=40.5g/15cm³

=2.7 g/cm³

=2700 kg/m³

Answer:

the above

Explanation:

heat the metal until it melts

react it with o2

stretch it

react it with acid

Answer:alloy

Explanation:

He can use alloy to change the metal.An alloy is the mixture of two or more metal.

Zn(s) + 2HCl (aq) -----> ZnCl​​​2 (aq) + H​​​​​​2 (g)

Here rate of reaction depends upon twice of the concentration of HCl.

Thus if concentration of HCl is lowered, rate of the reaction will be lowered and less ZnCl​2 will be produced.

Thus answer is (B) The reaction will be slow down.

Answer:

1) 0.0625  g.

2) 0.0125 g.

Explanation:

1) A solution of NaOH has a concentration of 25.00% by mass. What mass of NaOH is present in 0.250 g of this solution?

mass% of NaOH = [(mass of NaOH)/(mass of solution)] x 100.

mass% of NaOH = 25.0%, mass of NaOH = ???  g, mass of solution = 0.250 g.

∴ mass of NaOH = (mass% of NaOH)(mass of solution)/100 = (25.0%)(0.250 g)/100 = 0.0625  g.

2) What mass of NaOH must be added to the solution to increase the concentration to 30.00% by mass?

We can use the relation:

mass% of NaOH = [(mass of NaOH)/(mass of solution)] x 100.

mass% of NaOH = 30.0%, mass of NaOH = ???  g, mass of solution = 0.250 g.

∴ mass of NaOH = (mass% of NaOH)(mass of solution)/100 = (30.0%)(0.250 g)/100 = 0.075  g.

∴ The mass of NaOH should be added = 0.075 - 0.0625 = 0.0125 g.

Answer:

1) 0.0625  g.

2) 0.0125 g.

3) 80.0 g

Explanation:

edge

Answer:

False

Explanation:

Max Planck's theory of the duality of energy shows that the frequency radiation "v" can be regenerated only if an oscillator of such frequency has acquired the minimum energy required to initiate oscillation. At low temperatures, there is not enough energy available to induce high-frequency oscillations; in this way, the object does not regenerate ultraviolet radiation, ending the ultraviolet catastrophe.

Albert Einstein used this Max Planck hypothesis to explain the results obtained in his work on the photoelectric effect in 1905. Einstein did not refute Max's theory.

Albert Einstein's discovery of quanta does not disprove Max Planck's hypothesis about the dual nature of energy   i.e. False

Max Planck's hypothesis ( quantum hypothesis ) on the radiation of a black body states that energy from light can only be absorbed and radiated in discrete bundles ( quanta ), and this formed the basis on which Albert Einstein explained the results he obtained from his photo electric effect experiment he carried out.  therefore we can conclude that Einstein did not disprove Max Planck's hypothesis.

Hence we can conclude that Albert Einstein's discovery of quanta did not disprove Max Planck's hypothesis about the dual nature of energy.

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Answer:

the strongest intermolecular forces

Explanation:

The broken lines depicts hydrogen bonding. Hydrogen bonds are intermolecular forces are they are very strong bonds. These bonds are special dipole-dipole attractions between polar molecules in which hydrogen atom is directly joined to a highly electronegative atom usually oxygen or nitrogen or fluorine.

The broken lines shows the intermolecular attraction.

Answer:

A lunar eclipse occurs when the Moon enters the Earth's shadow. A solar eclipse occurs when the Moon's shadow falls on the Earth. They do not happen every month because the Earth's orbit around the sun is not in the same plane as the Moon's orbit around the Earth.

Answer:

50%

Explanation:

You would have to do 15 divided by 30 x 100 to get 50

Percentage Yield = Actual Yield divided by Theoretical Yield

Hope this is right and helpful

Answer:

No heat is released.

Explanation:

A substance absorbs heat when it melts.

The formula for the heat absorbed is

[tex]q = m\Delta_{\text{fus}}H[/tex]

Data:

m = 10 g

\Delta_{fus) H=\text{334 J/g}

Calculations:

[tex]q = 10 \times 334 = \text{3340 J = 3.34 kJ}\\\text{The ice }\boxed{\textbf{absorbs 3.34 kJ}} \text{ when it melts}.[/tex]

The energy released when the given mass of the ice melts is 3,340 J.

The energy released when the given mass of the ice melts is determined by taking the product of mass and heat of fusion of the ice.

Q = mH

where;

Substitute the given parameters and solve for the energy released when the ice melts.

Q = 10 x 334

Q = 3,340 J

Thus, the energy released when the given mass of the ice melts is 3,340 J.

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Final answer:

The ground state electron configuration for an atom of sodium at STP is 1s²2s²2p⁶3s¹, or in noble gas shorthand notation, [Ne] 3s¹.

Explanation:

The electron configuration of an atom of sodium (Na) in the ground state at standard temperature and pressure (STP) is represented by 1s²2s²2p⁶3s¹. This notation indicates that sodium has two electrons in the 1s orbital, two electrons in the 2s orbital, six electrons in the 2p orbital, and one valence electron in the 3s orbital. In noble gas configuration, this is abbreviated as [Ne] 3s¹, where [Ne] signifies the electron configuration of neon, the noble gas preceding sodium on the periodic table, and the 3s¹ represents the one valence electron in the third shell.

The ground state electron configuration for an atom of sodium at STP is 1s²2s²2p⁶3s¹, which can also be represented using noble gas notation as [Ne] 3s¹.

The electron configuration that represents the electrons in an atom of sodium in the ground state at STP is 1s²2s²2p⁶3s¹. This configuration indicates that sodium has two electrons in the first shell (1s), eight electrons filling the second shell (2s and 2p), and one valence electron in the third shell (3s). To represent this configuration using the noble gas notation, we use the symbol [Ne], which stands for the electron configuration of neon, the noble gas that precedes sodium on the periodic table. Thus, the noble gas configuration for sodium is [Ne] 3s¹.

Answer:

C₂H₂O₃

Explanation:

The empirical formula of a compound is derived bu finding the whole ratios of the constituent elements.

In succinic acid, the ratios of carbon to hydrogen to oxygen is calculated as follows:

% mass

Carbon- 40.60

Hydrogen - 5.18

Oxygen - 54.22

RAM

Carbon -12

Oxygen - 15.994

Hydrogen -1.008

No of moles elements in the compound

Carbon = 40.60/12=3.3833

Oxygen = 54.22/15.994= 3.39

Hydrogen= 5.18/1.008 = 5.1389

Mole ratios of the individual elements we divide by the smallest value of the number of moles.

Carbon: Hydrogen : Oxygen

3.3833/3.3833:3.39/3.3833:5.1389/3.3833

=1:1:1.5

We can multiply the value by 2 to get the whole number ratio.

=2:2:3

The empirical formula will be:

C₂H₂O₃

Answer:

c. 5 × 10⁴ barleycorn

Explanation:

It is given that:

1 barleycorn = 1/3 of an inch

Convert 1 barleycorn into meter (m) units

1 inch = 2.54 cm

since 100 cm = 1 m

1 inch = 0.0254 m

Therefore 1/3 of an inch = [tex]\frac{1}{3} *0.0254 = 0.00847 m[/tex]

therefore:

1 barleycorn = 8.47*10⁻³ m

The height of the empire state building of 449 m would be:

[tex]=\frac{1\ barleycorn*449 m}{8.47*10^{-3} m} = 5.3*10^{4}\ barleycorn[/tex]

Final answer:

The height of the Empire State Building, when converted from 449 meters to barleycorns, is approximately 53,040 barleycorns, which corresponds to the option c. 5 × 10⁴ barleycorns.

Explanation:

To convert the height of the Empire State Building from meters to barleycorns, we follow a two-step process. First, we convert the meters to inches, and then we convert the inches to barleycorns.

The Empire State Building is 449 meters tall. To convert meters to inches, we use the conversion rate, where 1 meter is approximately 39.37 inches.

Next, since 1 barleycorn is equal to 1/3 of an inch, we divide the number of inches by 1/3 to find the number of barleycorns:

When rounded to the nearest integer, we get 53,040 barleycorns, which corresponds to option c. 5 × 104 barleycorns.

Answer:

[tex]\boxed{\text{20 g}}[/tex]

Explanation:

We can use the Ideal Gas Law to solve this problem

pV = nRT

Data:

p = 1.02 atm

V = 15 L

T = 28 °C

Calculations:

(a) Convert temperature to kelvins

T = (28 + 273.15) K =  301.15 K

(b) Calculate the number of moles

[tex]\text{1.02 atm} \times\text{15 L} = n \times \text{0.082 06 L}\cdot\text{atm}\cdot\text{K}^{-1}\text{mol}^{-1}\times \text{301.15 K}\\\\15.3 = n \times \text{24.71 mol}^{-1}\\\\n = \dfrac{15.3}{\text{24.71 mol}^{-1}} = \text{0.619 mol}[/tex]

(c) Calculate the mass

[tex]\text{Molar mass} = \dfrac{\text{mass}}{\text{moles}}\\\\M = \dfrac{m}{n}\\\\\text{32.00 g}\cdot \text{mol}^{-1} = \dfrac{m}{\text{0.619 mol}}\\\\m = 32.00 \times 0.619 \text{ g} = \textbf{20 g}\\\\\text{The mass of oxygen is } \boxed{\textbf{20 g}}[/tex]

Answer:

argon

Explanation:

argon inhibits evaporation, and prevents corrosion

Argon is the best gas to use for inflating a balloon that must remain inflated for a long period of time because it doesn't escape from the balloon as quickly as hydrogen or helium and it is safer compared to oxygen and hydrogen.

Of the gases listed, argon is the best choice for inflating a balloon that needs to stay inflated for a long period of time. Helium is commonly used for inflating balloons because it is light and can make the balloon float, but it also diffuses through the balloon material quite fast causing the balloon to deflate over time. Argon, a noble gas, does not readily react with other substances and is heavier than air, thus it doesn't escape from balloon as quickly as helium or hydrogen, causing the balloon to remain inflated for longer. Oxygen, is not a feasible choice due to its reactive nature. Finally, Hydrogen is lighter than air, but it is highly flammable and when mixed with even a little oxygen, can become explosive.

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Answer:

The correct answer is option D.

Explanation:

In modern periodic table, elements are arranged in increasing order of a their atomic numbers in 7 horizontal and 18 vertical columns.

Horizontal rows are known as periods.

In his periodic table, elements in the same periods has same number of principle quantum number or shells.

Vertical columns are known as groups:

In his periodic table, elements having similar properties lied in the same vertical columns or groups because all the elements had same number of valence electrons or outer electrons.

Answer:

This solution is neutral.

Assumption: the solution is under room temperature, such that [tex]K_w = 10^{-14}[/tex].

Explanation:

For a solution in water,

[tex]\mathrm{[H_3O^{+}] \cdot [OH^{-}]} = \mathnormal{K_w}[/tex].

In other words, if [tex]K_w[/tex] is given, knowing the concentration (in [tex]\rm M[/tex], or equivalently [tex]\rm mol\cdot L^{-1}[/tex]) of either [tex]\rm H_3O^{+}[/tex] or [tex]\rm OH^{-}[/tex] will imply the concentration of the other ion.

Under room temperature,

[tex]K_w \approx 10^{-14}[/tex].

The question states that for this solution,

[tex]\mathrm{[H_3O^{+}]} = \rm 1.00\times 10^{-7}\; M[/tex]

As a result, the concentration of [tex]\rm OH^{-}[/tex] in this solution will be

[tex]\displaystyle \frac{K_w}{\mathrm{[H_3O^{+}]}} = \frac{10^{-14}}{1.00\times 10^{-7}} = 10^{-7}[/tex].

In this case, [tex]\rm [H_3O^{+}] = 10^{-7}\; M = [OH^{-}][/tex]. In other words, this solution is neutral.

Answer:

the 2 liter contains more soda

Answer: the answer is C!

Heat is released during the process

Explanation:

This means that 285.8 kJ/mol is evolved when one mole of water is formed.

The term enthalpy of formation has to do with the energy that is released or absorbed when a molecule of water if formed from its constituents.

The fact that the enthalpy of formation of water is -285.8 kJ/mol implies that 285.8 kJ/mol is evolved when one mole of water is formed.

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Answer:

Copper ions are reduced into copper atoms.

Cu²⁺₍aq₎ + 2e⁻ →  Cu₍s₎

Explanation:

During electrolysis,  the positive H⁺ and Cu⁺ ions move to the negative cathode and negative OH⁻ and Cl⁻ ions move to the positive anode.

At cathode, copper ions are preferentially discharged due to the low electromotive force required to discharge them compared to the hydrogen ion. The copper ions gain the two electrons lost by the chloride ions when the are discharged. (2 Cl⁻₍aq₎ → Cl₂₍g₎ + 2e⁻)

Thus the half equation is as follows:

Cu²⁺₍aq₎ + 2e⁻ →  Cu₍s₎

Answer:

6.47 x 10⁵.

Explanation:

The results are reported to the fewest significant  figures.

So, the result should has 3 significant figures:

(2.08 x 10³)(3.11 x 10²) = 6.4688 x 10⁵.

• In a series of calculations, carry the extra digits through to  the final result, then round.

• If the digit to be removed :

✓ is less than 5, the preceding digit stays the same.

For example, 1.33 rounds to 1.3.

✓ is equal to or greater than 5, the preceding digit is

increased by 1. For example, 1.36 rounds to 1.4.

So, the result will be 6.4688 x 10⁵ = 6.47 x 10⁵.

Final answer:

To solve (2.08 \times 10³) (3.11 \times 10²), multiply the decimal parts, add the exponents, and express the answer to three significant figures, resulting in 6.47 \times 10⁵.

Explanation:

To solve the problem (2.08 \times 10³) (3.11 \times 10²), we need to multiply the two numbers, taking into account the exponent rules and significant figures.

Firstly, multiply the decimal numbers:

2.08 \times 3.11 = 6.4688

Next, add the exponents of 10:

10^3 \times 10² = 10⁽³⁺²⁾ = 10⁵

Now combine the two results:

6.4688 \times 10⁵

However, we need to express the answer to the correct number of significant figures. The first number has three significant figures while the second number has three significant figures, so our final answer should also have three significant figures.

The result should be rounded to:

6.47 \times 10⁵

We have rounded the number 6.4688 to 6.47 to match the three significant figures. This is our final answer, expressed in proper scientific notation with the correct number of significant figures and proper units.

Answer:

Explanation:

I usually just use approximate values for the elements on the periodic table. The reason for that is that everyone uses a different periodic table. Some are rounded others are more precise. Redo this problem with better numbers for the elements.

N = 14

H = 1

N2H4 = 2*14 + 4*1  

N2H4 = 28 + 4 = 32

If you are given 31 grams of N2H4 then the formula is

mols = given mass / molecular mass

mols = 31 / 32

moles = 0.97  

Now you have a problem . Is the answer 1.0 or is 0.9?

I think I would pick 1.0

Answer:

In the chemical industry, lithium-based batteries are working most efficiently and replacing nickel-cadmium batteries. To study a redox reaction in a lithium battery let's take the example of Lithium Cobalt Oxide(LiCoO2).

Following is the overall reaction taking place in Lithium Cobalt Oxide battery. Reduction and oxidation takes place at Cathode and Anode respectively. that is why it is called a redox reaction.

Reaction at cathode:

Cathode: CoO2+Li+e−→ LiCoO2 (Reduction)

Reaction at Anode:

Anode: LiC6→ C6+Li++e− (Oxidation)

Overall reaction:  

LiC6 + CoO2→ C6 + LiCoO2

Lewis acid is a chemical species that is able to accept an electron pair. In this case the silver ion Ag[tex]^{+}[/tex] is a lewis acid because it accepts a lone pair electrons form the ammonia :NH[tex]_{3}[/tex]

Answer:

Your answer is Ag+ have a good day

Explanation:

The practice of interlocking fingers and rubbing during hand washing is crucial for effective cleanliness. It ensures that dirt and germs from all areas of the hands, including between the fingers and under the nails, are removed.

The act of interlocking the fingers and rubbing them together while washing hands has an important role in maintaining cleanliness. This technique is crucial as it not only cleans the surfaces of the hands but it ensures that the spaces between the fingers, which can often harbor dirt and germs, also gets adequately cleaned. Similarly, the act of rubbing helps to physically dislodge dirt and microorganisms, enhancing the effectiveness of handwashing.

It's worth noting that the backs of the hands, the palms, and especially under the fingernails are areas that can house a good amount of dirt and germs. Therefore, special attention should be paid to these areas. The process of interlocking can help clean the nails and the spaces between the fingers effectively.

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Interlocking the fingers and rubbing during hand washing is key for cleaning the spaces between fingers, which helps remove germs and bacteria from hard-to-reach areas, contributing to effective hand hygiene.

The importance of interlocking the fingers and rubbing while washing hands is to ensure that the spaces between the fingers get thoroughly cleaned. This action helps to remove dirt, germs, and bacteria that might be present between fingers, which are areas that are commonly missed when washing hands. It is important to perform this action, along with washing all other parts of the hands, including the fingernails, palms, and the backs of the hands, to maintain good hygiene and prevent the spread of diseases.

Answer: If a substance is the limiting reactant, then it will be completely used by the time the reaction completes because it is the reactant that reacts completely and the reaction stops after it is completely used up.

Explanation:

Limiting reagent is a reagent as it limits the formation of product and Excess reagent is the reagent which is preset in excess.

For example: if 0.75 moles of HCl and 1.5 moles of magnesium are reacted together.

[tex]Mg(s)+2HCl(aq)\rightarrow MgCl_2(aq)+H_2(g)[/tex]

According to stoichiometry:

As 2 mole of [tex]HCl[/tex] reacts with 1 mole of [tex]Mg[/tex]

0.75 moles of [tex]HCl[/tex] will react with =[tex]\frac{1}{2}\times 0.75=0.38moles[/tex] of [tex]Mg[/tex]

[tex]HCl[/tex] is a limiting reagent as it limits the formation of product and Mg is an excess reagent as (1.5-0.38)=1.12 moles of magnesium are left unreacted.

Answer:  If a substance is the limiting reactant, then it will be fully consumed by the time the reaction completes because it is the reactant that reacts completely and the reaction cannot proceed further.

Answer:

The new equilibrium system shift to make more reactants.

Explanation:

Removing reactant:

so, removing some of the reactants will shift the system to make more reactants.

A solution with a pH of 5.9 has a hydrogen ion concentration of approximately 1.26 x 10^-6 M. The pH scale is inversely related to hydrogen ion concentration - lower pH values correlate with higher hydrogen ion concentrations.

The pH of a solution is directly related to its hydrogen ion concentration ([H+]). Since pH is the negative base-10 logarithm of the [H+], a solution with a pH of 5.9 will have a hydrogen ion concentration of 10^-5.9 M (Molar), or approximately 1.26 x 10^-6 M. This is because each unit decrease in pH value results in a ten-fold increase in [H+], so a lower pH would mean a higher [H+]. Similarly, a higher pH indicates a lower hydrogen ion concentration as the solution becomes more basic or alkaline.

It's worth mentioning that a pH value of 7 is considered neutral, such as in pure water. Values below 7 are acidic (greater concentration of [H+]) and values above 7 are basic or alkaline (lesser concentration of [H+]).

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Answer:

46.85kJ

Explanation:

The specific latent heat of vaporization of water is =2.3 x 10⁶ J kg-1.

The specific heat capacity of water = 4.2×10³J/kgK

The latent heat of fusion of water= 3.36×10⁵ J/kg

The specific heat capacity of ice=2.108×10³ J/kgK

The heat of lost due to cooling of ice is calculated as follows by adding the heat lost during condensation of water vapor to the heat lost during cooling the water to freezing point plus the heat lost during freezing plus the heat lost during cooling the ice to -32.0°C

=MLv+MCΔT(water)+MLf+MCΔT(ice) where Lv=latent heat of vaporization of water , and Lf is the latent heat of fusion ice.

=(0.015kg×2.3 x 10⁶ J/kg)+(0.015kg×4.2×10³J/kgK×100K)+(0.015kg×3.36×10⁵ J/kg)+(0.015kg× 2.108×10³ J/kgK)×32K

=34500J+6300J+5040J+1011.84J

=46851.84J

=46.85kJ

Answer:

amino acids and urea

Explanation:

Amino acids are the building blocks of all proteins. Proteins comprise not only structural components such as muscle, tissue and organs, but also enzymes and hormones essential for the functioning of all living things. Urea is a byproduct of protein digestion.