Why can’t you ice skate on a lake when it is not frozen?

Answer:

A) Sample B has more calcium carbonate molecules

Explanation:

M = Molar mass of calcium carbonate = 100.0869 g/mol

[tex]N_A[/tex] = Avogadro's number = [tex]6.022\times 10^{23}\ \text{mol}^{-1}[/tex]

For the 4.12 g sample

Moles of a substance is given by

[tex]n=\dfrac{m}{M}\\\Rightarrow n=\dfrac{4.12}{100.0869}\\\Rightarrow n=0.0411\ \text{mol}[/tex]

Number of molecules is given by

[tex]nN_A=0.0411\times 6.022\times 10^{23}=2.48\times 10^{22}\ \text{molecules}[/tex]

For the 19.37 g sample

[tex]n=\dfrac{19.37}{100.0869}\\\Rightarrow n=0.193\ \text{mol}[/tex]

Number of molecules is given by

[tex]nN_A=0.193\times 6.022\times 10^{23}=1.16\times 10^{23}\ \text{molecules}[/tex]

[tex]1.16\times 10^{23}\ \text{molecules}>2.48\times 10^{22}\ \text{molecules}[/tex]

So, sample B has more calcium carbonate molecules.

The ratio of the elements of carbon, oxygen, calcium atoms, ions, has to be same in both the samples otherwise the samples cannot be considered as calcium carbonate. Same is applicable for impurities. If there are impurites then the sample cannot be considered as calcium carbonate.

For the extraction of at least 95% of Y in water, 3 extractions are to be performed.

Distribution coefficient can be defined as the ratio of the concentration of solute in an organic solvent to water.

Distribution coefficient = [tex]\rm \dfrac{concentration\;in\;solvent}{concentration\;in\;water}[/tex]

Concentration in water = 100-X per 50 ml

Distribution coefficient = [tex]\rm \dfrac{\frac{X}{10} }{\frac{100-X}{50} }[/tex]

4 = [tex]\rm \dfrac{\frac{X}{10} }{\frac{100-X}{50} }[/tex]

4 = [tex]\rm \dfrac{50X}{1000-X}[/tex]

4000 - 4X = 50X

X = 74.1 %

Thus, after the first extraction, the amount of Y extracted is 74.1%.

We have to extract at least 95% of Y. Thus, the second extraction is performed.

Remaining y = 25.9%

The concentration in organic solvent = X per 10 ml

Concentration in water = 25.9 -X

Distribution coefficient = [tex]\rm \dfrac{\frac{X}{10} }{\frac{25.9-X}{50} }[/tex]

4 = [tex]\rm \dfrac{\frac{X}{10} }{\frac{25.9-X}{50} }[/tex]

4 = [tex]\rm \dfrac{50X}{259-X}[/tex]

1036 - 4X = 50X

X = 19.2%

Thus, after the second extraction the amount of Y extarcted = first extraction + second extraction

The amount of Y extracted = 74.1 + 19.2 %

The amount of Y extracted = 93.3%

The remaining Y for third extraction = 100 - 93.3

The remaining Y for the third extraction = 6.7%

Concentration in water = 100 - 6.7

Distribution coefficient = [tex]\rm \dfrac{\frac{X}{10} }{\frac{6.7-X}{50} }[/tex]

4 = [tex]\rm \dfrac{\frac{X}{10} }{\frac{6.7-X}{50} }[/tex]

4 = [tex]\rm \dfrac{50X}{67-X}[/tex]

268 - 4X = 50X

X = 5.0%

The total extraction after third extraction = 93.3 + 5%

The total extraction after third extraction = 98.3%.

Thus for the extraction of at least 95% of Y in water, 3 extractions are to be performed.

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Answer:

Deuterium and Lithium.

Explanation:

I searched it up on google.

Answer: Some salt is trapped between ice crystals, but most are left behind in the unfrozen seawater.

Explanation:

Answer: The salinity of the water increases

Explanation: Hope this helps!

Answer:

Kinetic energy

Explanation:

Fireworks convert chemical energy into kinetic energy to send them flying upward. Hope it is correct!

Answer:

0.0148 moles

Explanation:

Solid copper is oxidized with HNO₃:

Cu + 4HNO₃ → Cu²⁺ + 2 NO₃⁻ + 2H₂O + 2NO₂

Where 1 mole of Cu produce 1 mole of Cu²⁺ when nitric acid is in excess.

Moles of Cu that react (Molar mass Cu = 63.546g/mol):

0.94g * (1mol / 63.546g) = 0.0148 moles of Cu

And moles of Cu²⁺ produced are also:

Answer:

Mass =   51 g

Explanation:

Given data:

Mass of ammonia formed = ?

Number of moles of hydrogen = 4.50 mol

Solution:

Chemical equation:

N₂ + 3H₂     →     2NH₃

Now we will compare the moles of hydrogen and ammonia.

                H₂           :            NH₃

                  3           :              2

                 4.50       :           2/3×4.50 = 3 mol

Mass of ammonia formed:

Mass = number of moles × molar mass

Mass = 3 mol × 17 g/mol

Mass =   51 g

Answer:

C |||| It is not practical because it takes a huge amount of water to produce a new pair of jeans

Explanation:

If you're doing flvs then it's C.

Answer:

C!

Explanation:

i got it right on the test UwU

Answer:

MgS Magnesium sulfide

Answer:

6.36  g AgCl

Hope this helps!

Answer:

(a). Kindly check the explanation section.

(b). 24.5 M^-1 cm^-

(c). 0.0318 M

Explanation:

So, we are given the following data parameters which is going to aid us in solving the above Question;

The path length = 1cm, extinction coefficient = unknown, absorbance is unknown and concentration= 0.02mM.

Using the formula below; we can determine the extinction coefficient as;

Absorbance = extinction coefficient × concentration × path length. -----------(1).

(a). Since, the absorbance is not given in the Question it won't be possible to determine the value of the extinction coefficient. Thus, say the value of absorbance = A.

Then, extinction coefficient = A/ 0.02 × 1 cm.

(b). Making use of the formula above, the extinction coefficient can be Determine as follows;

extinction coefficient = 1.84/0.075 × 1 = 24.5 M^-1 cm^-1.

(c). The concentration can be Determine by also making use of the formula above and making the concentration the subject of the formula;

Concentration = absorbance/ extinction coefficient × path length.

Concentration = 0.78/24.5 M^-1 cm^-1. × 1cm = 0.0318 M.

Answer:

the mole fraction of water in a solution is 0.17

Explanation:

The computation of the mole fraction of water in a solution is shown below:

Given that

Ethanol be 8.0 mol

And, the water be 1.6 mol

Based on the above information, the mole fraction of water in a solution is

= Water ÷ (Water + ethanol)

= 1.6 mol ÷ (1.6 mol + 8.0 mol)

= 1.6 mol ÷ 9.6 mol

= 0.17

Hence, the mole fraction of water in a solution is 0.17

Answer:

8.52 m/s

Explanation:

Step 1: Given data

Step 2: Convert "T" to the Kelvin scale

When working with gases, we need to consider the absolute temperature. We will convert from Celsius to Kelvin using the following expression.

K = °C + 273.15 = -16 + 273.15 = 257 K

Step 3: Calculate the root mean square speed of the gas

The root mean square speed measures the average speed of particles in a gas. We will calculate it using the following expression.

[tex]v_{rms} = \sqrt{\frac{3 \times R \times T}{M} } = \sqrt{\frac{3 \times 8.314 J/mol.K \times 257 K}{88.30 g/mol} } = 8.52 m/s[/tex]

Answer:

1,002.936 g

Explanation:

The combustion equation of each will be;

CH4 + 2O2 = CO2 + H2O

C3H8 + 5O2 = 3CO2 + 4H2O

We are told the mixture is 344g.

Thus;

For CH4 combustion;

Amount of CH4 = 0.336 × 344 = 115.584g

Molar mass of CH4 is 16 g/mol

Number of moles of CH4 is;

n = 115.584g/(16 g/mol)

n = 7.224 moles

n(CO2) = n(CH4) = 7.224 moles

For C3H8 combustion;

Amount of C3H8 = 0.664 × 344 = 228.416 g

Molar mass of C3H8 = 44 g/mol

Thus;

Number of moles of C3H8 = 228.416 g/(44 g/mol) = 5.19 mol

n(CO2) = 3n(C3H8) = 3 × 5.19 = 15.57 moles

Total moles of CO2 = 7.224 moles + 15.57 moles = 22.794 mol

Molar mass of CO2 = 44 g/mol

Thus amount of CO2 by mass = 22.794 mol × 44 g/mol = 1,002.936 g

Answer:

D. 3 Co²⁺(aq) + 2 PO₄³⁻(aq) ⇒ Co₃(PO₄)₂(s)

Explanation:

The complete ionic equation includes all the ions and the insoluble species. Let's consider the following complete ionic equation.

3 Co²⁺(aq) + 6 NO₃⁻(aq) + 6 Na⁺(aq) + 2 PO₄³⁻(aq) ⇒ Co₃(PO₄)₂(s) + 6 Na⁺(aq) + 6 NO₃⁻(aq)

The net ionic equation includes only the ions that participate in the reaction (not spectator ions) and the insoluble species. The corresponding net ionic equation is:

3 Co²⁺(aq) + 2 PO₄³⁻(aq) ⇒ Co₃(PO₄)₂(s)

Answer:

they use it when a living organism dies.

Explanation:

when d organism decomposes carbon is released that enters back into d earth. this follows d law of mass

Answer:

450 grams of Na2SO4

Explanation:

hope that helps

Answer:

V₂ = 4.4 L

Explanation:

Given data:

Initial volume = 5.5 L

Initial pressure = 650 mmHg (650/760 =0.86 atm)

Initial temperature = 20 °C (20 +273 = 293 K)

Final temperature = 273 K

Final volume = ?

Final pressure =  1 atm

Solution:

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

V₂ =  P₁V₁T₂/T₁ P₂

V₂ = 0.86 atm× 5.5 L × 273 K / 293 k × 1 atm

V₂ = 1291.29 atm.K.L / 293 k.atm

V₂ = 4.4 L

Answer: C

Explanation:

A. As they do not have a given shape and expand to fill the container, modifying the size of the container modifies the space the gas occupies

B. They are nearly free molecules, which means no bound between them, moving fast and freely around the container

C. NOT A PROPERTY. As said before, as there are no bindings between molecules and move freely, they cannot have a fixed size cause they're always on the move.

D. Because they expand to fill the container, it's easy to them to occupy more space than in any other state, as the container is the only thing that defines how much volume they occupy

Answer:

[tex]V = 0.117 \ L[/tex]

General Formulas and Concepts:

Chem

Explanation:

Step 1: Define

1.57 M KOH (potassium hydroxide)

10.3 g KOH

Step 2: Define conversions

Molar Mass of K - 39.10 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of H - 1.01 g/mol

Molar Mass of KOH - 39.10 + 16.00 + 1.01 = 56.11 g/mol

Step 3: Convert

[tex]10.3 \ g \ KOH(\frac{1 \ mol \ KOH}{56.11 \ g \ KOH} )[/tex] = 0.183568 mol KOH

Step 4: Solve for Volume

Step 5: Check

We are given 3 sig figs. Follow sig fig rules.

[tex]0.116922 \ L \approx 0.117 \ L[/tex]

Answer:

Bromine is a very reactive element. While it is less reactive than fluorine or chlorine, it is more reactive than iodine. It reacts with many metals, sometimes very vigorously. For instance, with potassium, it reacts explosively.

Explanation:

Answer: Bromine is a high reactive element. While it is not as reactive as fluorine or chlorine, it is still more reactive than iodine. It reacts with many metals, and even sometimes very aggressively. For example, when mixed with potassium, it will explode.  

Explanation:

Answer:

Answer. Answer: Nitrogen (N), antimony (Sb), bismuth (Bi) is the order from least conductive to most conductive.

Answer:

nitrogen (N), antimony (Sb), bismuth (Bi)

Answer: 1M

Explanation:

Molarity = mols/L

moles of lead bromide: 183.51/ 367.0 = 0.5 mol

500 ml/ 1000 mL = .5L

.5 mol / .5 L = 1 mol/L = 1M

Answer:

Explanation:

average kinetic energy of a gas molecule really only depends on the temperature, so which ever container is at the highest temperature is the answer

In comparison to other fundamental states of matter, plasma has the highest kinetic energy. This is due to the fact that particles in a plasma travel more quickly than those in a corresponding solid, liquid, or gas.

The energy that an object has as a result of motion is known as kinetic energy. It is described as the effort required to move a mass-determined body from rest to the indicated velocity. The body holds onto the kinetic energy it acquired during its acceleration until its speed changes.

The reason why molecules in gases have the largest kinetic energy is because they have more space between one another, experience less intermolecular force, and travel at a faster rate, which results in higher energy.

The temperature has a direct impact on the average kinetic energy of the particles inside a container.

Thus, In comparison to other fundamental states of matter, plasma has the highest kinetic energy.

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Answer:

b.  growth in the size of the mineral grains

Explanation:

Non-foliated texture shown by a metamorphic change is depicted by growth in the size of the mineral grains.

Answer:

its b home slice

Explanation:

Answer:

5 valence elctrons

Explanation:

the outer most orbitals, 3s2 and 3p3 contains 5 electrons, thus valences electrons for P is 5

Answer:

16.00 g/mol

Explanation:

Answer:

16.00 g/mol

Explination:

1 mol of calcium phosphate contains 8 moles of oxygen. From this, we can compute for the amount of oxygen in grams using the molar mass of oxygen, which is 16.00 g/mol.

Answer:

[tex]ionization=1.74\%[/tex]

Explanation:

Hello!

In this case, since the degree of ionization of an acid is computed in terms of the concentration of hydrogen ions and the initial concentration of the acid:

[tex]ionization=\frac{[H^+]}{[HA]} *100\%[/tex]

Because the ionization reaction is represented by:

[tex]HA\rightleftharpoons H^++A^-[/tex]

Therefore, the degree or percent ionization turns out:

[tex]ionization=\frac{0.00417M}{0.240M} *100\%\\\\ionization=1.74\%[/tex]

Best regards!

The final temperature of the liquid water after all the ice has melted is equal to 25°C.

The specific heat capacity can be described as the quantity of heat needed to raise the temperature in one unit (1kg) of substance by one-degree Celcius.

The formula to show the relationship between the specific heat capacity and heat absorbed or lost is:

Q = mCΔT

Given, the amount of ice, m = 100g

The amount of water, M = 300g

The specific heat capacity of the water, C = 1 cal /g°C

The heat of fusion of ice, C = 80 cal/g

Heat given by water = Heat taken by ice + Heat taken by water formed from ice

300 × 1 ×(60 - T) = 100 × 80  + 100 × 1 ×T

18000 - 300 T = 8000 + 100 T

400 T = 10000

T = 25°C

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Answer:

Younger/newer

Explanation:

Stratagraphic means an intrusion or fault is younger than the layer it affects.