Give four examples illustrating each of the following terms. a. homogeneous mixture b. heterogeneous mixture c. compound e. physical change d. element f. chemical change

Answer:

Robert Millikan was a physicist who discovered the elementary charge of an electron using the oil-drop experiment

Answer:

the mass of an electron using the Oil-Drop experiment.

Explanation:

Answer:

Hence the Solubility product,  

Ksp = [Ca2+] [Cl-]2  

or, Ksp = (4.5) (9)2  

or, Ksp = 364.5

Explanation:  

Mass of CaCl2 = 4.99 g  

Molar mass of CaCl2 = 110.98 g/mol  

Moles of CaCl2  

= given mass/ molar mass  

= 4.99/ 110.98  

= 0.045  

Volume = 10.0 mL = 0.01 L  

CaCl2 dissociates into its ion as:  

CaCl2 (s)  \rightleftharpoons Ca2+ (aq) + 2 Cl- (aq)  

At 90°C, the solution is saturated with Ca2+ and Cl- ions.

Moles of Ca2+ = Moles of CaCl2 dissolved = 0.045  

Moles of Cl- = 2 x ( Moles of CaCl2 dissolved) = 2 x 0.045 = 0.09

[Ca2+] = Moles/ Volume = 0.045/ 0.01 = 4.5 M  

[Cl-] = 0.09/ 0.01 = 9 M  

Solubility product,  

Ksp = [Ca2+] [Cl-]2  

or, Ksp = (4.5) (9)2  

or, Ksp = 364.5

Thermochemistry has to do with  heat evolved or absorbed in a chemical reactions. Thermochemical equations are equations in which the heat of reaction is included in the reaction equation. The reaction of moles and heat of reaction is important here.

This question has to do with thermochemistry and thermochemical equations.

The answers to each of the questions are shown below;

a) 300.52 KJ

b) 11.39 g

c) 5.78 g

The equation of the thermochemical reaction is;

2C12H26 + 37O2-------> 24CO2 + 15026KJ

Number of moles of CO2 released = 21.3g/44g/mol = 0.48 moles

From the reaction equation;

15026KJ is released when 24 moles of CO2 is released

x KJ is released when  0.48 moles of CO2 is released

x = 15026KJ  * 0.48 moles/24 moles

x = 300.52 KJ

b) If 2 moles of C12H26 released 15026KJ of heat

     x moles of C12H26  released 500.00KJ

x = 2 * 500.00KJ/15026KJ

x = 0.067 moles

Mass of C12H26 consumed =  0.067 moles * 170 g/mol = 11.39 g

c) Heat gained by water = heat released by combustion of kerosene

Heat gained by water = 0.75 Kg * 4200  * (90 -10)

Heat gained by water = 252 KJ

If 2 moles of C12H26  produced 15026KJ

x moles of C12H26  produces 252 KJ

x = 2 * 252/15026

x = 0.034 moles

Mass of C12H26   = 0.034 moles *  170 g/mol = 5.78 g

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Answer:

A₅B₄

Explanation:

Since we have one atom of element A at the center of each face of the unit cell, since the unit cell is a cubic cell, we have 6 faces. Since the atom on the face of the unit cell is shared with another cell, we have half of it in the unit cell is shared So, the number of atoms per face is 1/2 atom/face × 6 faces = 4 atoms on the faces of the unit cell.

Also, we have 1 atom at each corner of the cubic unit cell. Since there are 8 corner in the cubic unit cell. Also, each atom at the corner is shared with 8 unit cells, so we have 1/8 atom per corner. So, the number of atoms per unit cell is 1/8 atom/corner × 8 corners = 1 atoms at the corners of the unit cell.

So, in total we have 4 + 1 = 5 atoms of element A in the unit cell.

Also, there are 4 atoms of element B in the unit cell.

So, the ratio of atoms of element A to element B is 5 : 4.

A:B = 5:4

So, the empirical formula of the compound containing elements A and B is A₅B₄

Answer:

C

Explanation:

if we were to followw the IUPAC

Answer:

Explanation:

1. A solution is made by dissolving 5.84g of NaCl is enough distilled water to a give a final volume of 1.00L. What is the molarity of the solution? a. 0.100 M b. 1.00 M c. 0.0250 M d. 0.400 M 2. A 0.9% NaCl (w/w) solution in water is a. is made by mixing 0.9 moles of NaCl in a 100 moles of water b. made and has the same final volume as 0.9% solution in ethyl alcohol c. a solution that boils at or above 100°C d. All the above (don't choose this one) 3. In an exergonic process, the system a. gains energy b. loses energy c. either gains or loses energy d. no energy change at all

Answer:

[tex]\boxed {\boxed {\sf 0.100 \ M }}[/tex]

Explanation:

Molarity is a measure of concentration in moles per liter.

[tex]molarity = \frac{moles \ of \ solute}{liters \ of \ solution}}[/tex]

The solution has 5.84 grams of sodium chloride or NaCl and a volume of 1.00 liters.

We are given the mass of solute in grams, so we must convert to moles. This requires the molar mass, or the mass of 1 mole of a substance. These values are found on the Periodic Table as the atomic masses, but the units are grams per mole, not atomic mass units.

We have the compound sodium chloride, so look up the molar masses of the individual elements: sodium and chlorine.

The chemical formula (NaCl) contains no subscripts, so there is 1 mole of each element in 1 mole of the compound. Add the 2 molar masses to find the compound's molar mass.

There are 58.4397693 grams of sodium chloride in 1 mole. We will use dimensional analysis and create a ratio using this information.

[tex]\frac {58.4397693 \ g\ \ NaCl} {1 \ mol \ NaCl}[/tex]

We are converting 5.84 grams to moles, so we multiply by that value.

[tex]5.84 \ g \ NaCl *\frac {58.4397693 \ g\ NaCl} {1 \ mol \ NaCl}[/tex]

Flip the ratio. It remains equivalent and the units of grams of sodium chloride cancel.

[tex]5.84 \ g \ NaCl *\frac {1 \ mol \ NaCl}{58.4397693 \ g\ NaCl}[/tex]

[tex]5.84 *\frac {1 \ mol \ NaCl}{58.4397693 }[/tex]

[tex]0.09993194823 \ mol \ NaCl[/tex]

We can use the number of moles we just calculated to find the molarity. Remember there is 1 liter of solution.

[tex]molarity= \frac{moles \ of \ solute}{liters \ of \ solution}[/tex]

[tex]molarity= \frac{ 0.09993194823 \ mol \ NaCl}{1 \ L}[/tex]

[tex]molarity= 0.09993194823 \ mol \ NaCl/L[/tex]

The original measurements of mass and volume have 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandths place. The 9 in the ten-thousandths place tells us to round the 9 to a 0, but then we must also the next 9 to a 0, and the 0 to a 1.

[tex]molarity \approx 0.100 \ mol \ NaCl/L[/tex]

1 mole per liter is 1 molar or M. We can convert the units.

[tex]molarity \approx 0.100 \ M \ NaCl[/tex]

The molarity of the solution is 0.100 M.

Where are the questions?

Answer:

48.67 seconds

Explanation:

From;

1/[A] = kt + 1/[A]o

[A] = concentration at time t

t= time taken

k= rate constant

[A]o = initial concentration

Since [A] =[A]o - 0.75[A]o

[A] = 0.056 M - 0.042 M

[A] = 0.014 M

1/0.014 = (1.1t) + 1/0.056

71.4 - 17.86 = 1.1t

53.54 = 1.1t

t= 53.54/1.1

t= 48.67 seconds

Hence,it takes 48.67 seconds to decompose.

Answer:

10 ms-1

Explanation:

Kinetic energy = 1/2 × m × v^2

1 = 1/2× 20 ×10^ -3 × v^2

v ^ 2 = 100

v = 10 ms-1

note : convert grams in to kg before substitution as above

Given:

Kinetic energy,

Mass,

We know the formula,

→ [tex]K.E = \frac{1}{2} mv^2[/tex]

By putting the values, we get

       [tex]1 = \frac{1}{2}\times 20\times 10^{-3}\times (v)^2[/tex]

     [tex]v^2 = 100[/tex]

       [tex]v = \sqrt{100}[/tex]

       [tex]v = 10 \ m/s[/tex]

Thus the above response is correct.

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The name of the compound shown below is 1- pentene. The correct answer is option D.

A compound is a substance made up of two or more different elements chemically bonded together in a fixed ratio.

1-pentene is an unsaturated hydrocarbon with the chemical formula [tex]\rm C_5H_{10}[/tex]. It is an alkene, which means it contains a carbon-carbon double bond.

Therefore, option D. 1-pentene is the name of the compound shown.

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Answer:

"They established the laws of planetary motion"

Explanation:

Mr. Kepler was the astronomer who came up with the "Laws of Planetary Motion."

Answer:

Explanation:  Độ thẩm thấu của NaCl 0.9% và glucose 5% lần lượt là 308 và 278 ... Dung dịch natri clorid sử dụng trong pha thuốc tiêm truyền thường dùng

Answer:

The mole ratio of AgNO3 to Ag2SO4 IS 2:1 .0.657 g Ag2SO4 x 1 mol / 312 g = 0.00211 mol Ag2SO4.

0.00211 mol Ag2SO4 x 2 mol AgNO3 / 1 mol Ag2SO4 = 0.00421 mol AgNO3

0.00421 mol AgNO3 x 1 L / 0.123 mol AgNO3 = 0.0342 L = 34.2 mL of AgNO3 solution.Therefore,34.2ml of 0.123M AgNO3 will be required.

Answer:

Molar mass = 180 g/mol

Explanation:

Relative Atomic Mass of C = 12

of H = 1

of O =16

Let Molar mass be mm

mm of C6H12O6 = 6(12) + 12(1) + 6(16)

= 72 + 12 + 96 = 180 g/mol

Answer:

Element

Element : A pure substance composed of the same type of atom throughout. Compound : A substance made of two or more elements that are chemically combined in fixed amounts.

Explanation:

[tex]\\ \large\sf\longmapsto KNO_3[/tex]

[tex]\\ \large\sf\longmapsto 39u+14u+3(16u)[/tex]

[tex]\\ \large\sf\longmapsto 53u+48u[/tex]

[tex]\\ \large\sf\longmapsto 101u[/tex]

[tex]\\ \large\sf\longmapsto 101g/mol[/tex]

Now

[tex]\boxed{\sf No\:of\:moles=\dfrac{Given\:mass}{Molar\:mass}}[/tex]

[tex]\\ \large\sf\longmapsto No\:of\:moles=\dfrac{0.565}{101}[/tex]

[tex]\\ \large\sf\longmapsto No\:of\:moles=0.005mol[/tex]

We know

[tex]\boxed{\sf Molarity=\dfrac{Moles\:of\:solute}{Vol\:of\:Solution\:in\:L}}[/tex]

[tex]\\ \large\sf\longmapsto Molarity=\dfrac{0.005}{\dfrac{250}{1000}L}[/tex]

[tex]\\ \large\sf\longmapsto Molarity=\dfrac{0.005}{0.250}[/tex]

[tex]\\ \large\sf\longmapsto Molarity=0.02M[/tex]

[tex] \: \: \: \: \: \: \: \: \: [/tex]

Answer:

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Answer:

helps

Explanation:

Answer:

M of HNO₃ is 0.119M

Explanation:

A basic concept of titration is that in equivalence point:

mmoles of acid = mmoles of base

We have data from base and we only have data from volume of acid.

In a case our titration is a strong acid against a strong base.

We apply formula:

M of acid . Vol of acid = M of base . Vol of base

M of acid . 21.8 mL = 0.137M . 19 mL

M of acid = (0.137M . 19 mL) / 21.8 mL

M of acid = 0.119 M

When we neutralize all the titrant we reach the equivalence point.

At this point, pH = 7

2HNO₃  +  Ca(OH)₂ → Ca(NO₃)₂ +  2H₂O

Answer:

90.99 or 91.0

Explanation:

Using the balanced equation, you convert 38.5g of ethanol to moles of water. From there, you plug the values into the Ideal Gas Equation: PV=nRT.

Answer: The volume of oxygen gas is 91.4 L.

Explanation:

The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)

Given mass of ethanol = 38.5 g

Molar mass of ethanol = 46 g/mol

Plugging values in equation 1:

[tex]\text{Moles of ethanol}=\frac{38.5g}{46g/mol}=0.840 mol[/tex]

The given chemical equation follows:

[tex]CH_3CH_2OH(g)+3O_2(g)\rightarrow 2CO_2(g)+3H_2O(g)[/tex]

By stoichiometry of the reaction:

If 1 mole of ethanol produces 3 moles of water

So, 0.840 moles of ethanol will produce = [tex]\frac{3}{1}\times 0.840=2.52mol[/tex] of water

The ideal gas equation is given as:

[tex]PV=nRT[/tex] .......(2)

where

P = pressure = 1.75 atm

V = volume of oxygen gas = ?

n = number of moles= 2.52 moles

R = Gas constant = 0.0821 L.atm/mol.K

T = temperature of the tank = [tex]500^oC=[500+273]K=773K[/tex]

Putting values in equation 2, we get:

[tex]1.75 atm\times V=2.52mol\times 0.0821L.atm/mol.K\times 773K\\\\V=\frac{2.52\times 0.0821\times 773}{1.75}=91.4L[/tex]

Hence, the volume of oxygen gas is 91.4 L.

Answer:

See explanation and image attached

Explanation:

The product of the Grignard reaction between methyl benzoate and excess phenylmagnesium bromide is triphenyl methanol.

The reaction proceeds by nucleophillic reaction as the carbonyl moiety is attacked. A tetrahedral intermediate is formed. Loss of the -OMe group is accompanied by the attack of the first molecule of PhMgBr.

Attack by a second PhMgBr molecule yields trimethyl phenoxide. Protonation of this specie yields the final product which is obtained by aqueous workup.

Answer:

5.75L is the volume of the sample after the reaction

Explanation:

Based on the reaction, 1 mole of H2 reacts with 1 mole of O2 to produce 1 mole of H2O2.

As in the reaction, 0.1200 moles of H2 and 0.1200 moles of O2 are added, 0.1200 moles of H2O2 are produced.

Before the reaction, the moles of gas are 0.2400 moles and after the reaction the moles are 0.1200 moles of gas.

Based on Avogadro's law, the moles of a gas are directly proportional to the volume under temperatura and pressure constant. The equation is:

V1/n1 = V2/n2

Where V is volume and n are moles of 1, initial state and 2, final state.

Replacing:

V1 = 11.5L

n1 = 0.2400 moles

V2 = ?

n2 = 0.1200 moles

11.5L*0.1200 moles / 0.2400 moles = V2

V2 = 5.75L is the volume of the sample after the reaction

Explanation:

[tex]57816 \: moles[/tex]

are present in 4.20x10^24 atoms of Pb

Answer:

7 moles

Explanation:

(4.2*10^24)/(6*10^23)=7

Answer:

4.54 atm

Explanation:

Step 1: Calculate the total number of gaseous moles

We will calculate the moles of each gas using its molar mass.

He: 5.25 g × 1 mol/4.00 g = 1.31 mol

N₂: 3.25 g × 1 mol/28.01 g = 0.116 mol

The total number of moles is:

n = 1.31 mol + 0.116 mol = 1.43 mol

Step 2: Convert 27 °C to Kelvin

We will use the following expression.

K = °C + 273.15 = 27 + 273.15 = 300 K

Step 3: Calculate the total pressure of the mixture

We will use the ideal gas equation.

P × V = n × R × T

P = n × R × T / V

P = 1.43 mol × (0.0821 atm.L/mol.K) × 300 K / 7.75 L = 4.54 atm