How many molecules of sodium oxide will be created if 275 grams of sodium reacts with excess oxygen? Given the equation: 4Na + O2 -> 2Na2O

Answer:

c. 1.0 mole C5H5N and 1.5 mole C5H5NHCl

Explanation:

We can determine pH of a buffer using H-H equation:

pH = pKa + log [A⁻] / [HA]

Where [A⁻] is concentration of conjugate base and [HA] concentration of weak acid. These concentrations can be computed as moles of each species.

We need to determine pKa of both NH₃ and C₅H₅N buffers, thus:

pKb = -log Kb

NH₃ pKb = -log 1.8x10⁻⁵ = 4.74

C₅H₅N pKb = -log 1.7x10⁻⁹ = 8.77

And pKa = 14 - pKb:

NH₃ pKa = 14 - 4.74 = 9.26

C₅H₅N pKb = 14 - 8.77 = 5.23

A buffer works only under pH's between pKa-1 and pKa + 1. As pKa NH₃ buffer is 9.23 is not possible to produce a buffer with pH 5.05 for this system.

Thus, we only will compute the buffers made with C₅H₅N:

c. 1.0 mole C5H5N (Weak base) and 1.5 mole C5H5NHCl (Conjugate acid)

pH = pKa + log [A⁻] / [HA]

pH = 5.23+ log [1.0 moles] / 1.5 moles]

d. 1.5 mole C5H5N and 1.0 mole C5H5NHCl

pH = pKa + log [A⁻] / [HA]

pH = 5.23+ log [1.5 moles] / 1.0 moles]

Right solution is:

Answer:

the volume of gas inside this balloon = 146.3 L

Explanation:

Given that:

The temperature T = 31 °C = ( 31 + 273.15 )K = 304.15 K

The air pressure P = 0.700 atm

number of moles of gas n = 4.10 moles

Gas constant = 0.0821 L atm/K/mol

The objective is to calculate the volume of the gas inside the ballon.

Using the Ideal gas equation

PV = nRT

V = nRT/P

V = (4.10×0.0821×304.15)/0.700

V = 102.3799/0.700

V = 146.257 L

V = 146.3 L

Thus, the volume of gas inside this balloon = 146.3 L

Answer:

As the car starts to slide down the ramp, it is kinetic energy and when it's on the top of the ramp,  it is potential energy. We can see that the energy is now being transferred through the car and ramp.

Answer:

oxygen is the chemical element with the atomic number is 8 and the symbol is o its known as called oxygen.

Explanation:

Oxygen is the most third element in the universe at they standard and temperature and pressure,and oxides most elements as other compounds.

Oxygen gas is the earth atmosphere is 21%, an oxygen is the half of the earth crust in form of oxide,oxygen is liquid and solid gas.

Oxygen atoms such as proteins and acids, fats the major organic compounds, oxygen as component of the water and carbon dioxide.

Oxygen has many characteristics :- properties and molecular structure:-

this  is a pressure and temperature  with molecular formula referred as oxygen,simply describe a double bond and molecular orbits.

Physical properties:- oxygen is highly substance and must be combustible materials, oxygen may also from using a liquid nitrogen coolant, molecular oxygen is the associated with the process of air glow.

Stellar origin :- all of the remaining to half lives to the majority of are less then milliseconds.

Occurrence:- oxygen is the process part of the element in the earth crust, free oxygen is also occurs in the world bodies.

Analysis :- analysis to the structure of vegetation and the carbon cycle on a global scale.

Answer:

Producer gas and water gas contain carbon monoxide and hydrogen.

Answer:

The pH of 500 cm³, 0.2 mol/dm³, Ca(OH₂) is ≈ 13.6

Explanation:

The given parameters are;

Concentration of the calcium hydroxide, Ca(OH₂) = 0.2 mol/dm³

Volume of the calcium hydroxide, Ca(OH₂) = 500 cm³

Given that the calcium hydroxide, Ca(OH₂),  undergoes complete ionization in water, complete dissociation, we have;

Ca(OH₂)  ⇄  Ca²⁺ + 2 OH⁻

Therefore, we have;

2 moles of [OH⁻] for each mole of Ca(OH₂) which gives the concentration of  [OH⁻] as

[OH⁻] = 2 × 0.2 ≈ 0.4 mol/dm³

The pH is given by the formula

pH = 14 + ㏒₁₀ [OH⁻]

pH = 14 + ㏒₁₀ (0.4) = 14 - 0.3979 = 13.6021 ≈ 13.6

The pH of the 500 cm³ 0.2 mol/dm³ Ca(OH₂) ≈ 13.6.

Answer:

Benzene

Explanation:

You have to find the freezing point for each of these (make sure they're in Celsius). You might want to double check these but:

Benzene: 5.5

Water: 0

Butane: -138

Nitrogen: -210

The substances that will solidify before the temperature reaches 0°C is benzene. The correct option is A.

Freezing, also known as solidification, is a phase transition that occurs when the temperature of a liquid falls below its freezing point.

If the intermolecular forces between its molecules are strong, the freezing point is high.

When the forces are weak, the freezing point is low. The freezing point of a liquid or the melting point of a solid occurs when the solid and liquid phases are in equilibrium.

Pure benzene has a freezing point of 5.48 degrees Celsius. Because of the salt in it, fresh water freezes at 32 degrees Fahrenheit, but seawater freezes at around 28.4 degrees Fahrenheit.

Thus, as per the given scenario, the correct option is A.

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Answer:

The answer is "Option B"

Explanation:

when we react with FeCl, iron, and chloride to both the electrolysis. So, iron is charged positive ion, as well as passes to the negative, is cathode electrode. But there is a decrease in the cathode.

The equation can be defined as follows:

[tex]FeCl_2[/tex] [tex]\longrightarrow[/tex][tex]Fe + Cl_2[/tex]

In the above equation, when the iron chloride electrolysis solution, it will give the iron(II) and the chlorine. This process happens when the hydrogen chloride solution at a temperature of about 90 ° C.

Answer: D

Explanation: As Fe is positive charged while chlorine is negative charged.

(D) is correct. As iron moves to negative and it get reduce as negative electrode is cathode

Answer:

conclusion

Explanation:

it can't be a hypothesis since tests are carried out to verify so it is not a theory

an introduction to an experiment only gives the basis of what we are investigating therefore nothing has been proven and the question is still unanswered

The overall takeaway of an experiment’s results is the conclusion. Hence, option C is correct.

A hypothesis is a testable statement about the relationship between two or more variables or a proposed explanation for some observed experiment.

The overall takeaway of an experiment’s results can't be a hypothesis since tests are carried out to verify so it is not a theory

An experiment only gives an idea about the investigation therefore nothing has been proven and the question is still unanswered.

Hence, the overall takeaway of an experiment’s results is the conclusion.

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Answer:

0.8833 mole of C3H8

Explanation:

Given:

Mass of C₃H₈ (Propane) = 38.95 gram

Computation:

Molar mass of C = 12.01

Molar mass of H = 1.008

Molar mass of C₃H₈ (Propane) = 3(12.01) + 8(1.008)

Molar mass of C₃H₈ (Propane) = 36.03 + 8.064

Molar mass of C₃H₈ (Propane) = 44.094

Number of mol in 38.95 gram Propane = Mass / Molar mass

Number of mol in 38.95 gram Propane = 38.95 / 44.094

Number of mol in 38.95 gram Propane = 0.88334

Answer:

Use the Periodic Table to find molar masses.

Propane (C3H8), a common fuel, reacts with oxygen to form carbon dioxide and water according to the equation below:

C3H8 + 5O2 → 3CO2 + 4H2O

If a propane heater burns 38.95 g C3H8, it consumes

38.95 mol C3H8.

0.8830 mol C3H8.

1 mol C3H8.

44.10 mol C3H8.

Part 2

How many moles of oxygen are required to produce 37.15 g CO2?

37.15 g CO2 = 1.407 mol O2

Part 3

What mass of propane is necessary to react with the amount of oxygen calculated in the previous question?

12.41   g C3H8    

If an object's mass is 70 g, and its volume is 10cm cubed,  its density is 7 centimeter cube.

The density of any solid substance is the unit of the area occupied by it in per centimeter of the cube of the volume in the given sample and calculated by dividing the mass and the volume of the compound unit will be centimeter cube.

The mass of the given object is 70 gram and the volume is given is 10 cm to find the density,

                       Density = mass of object / volume of object

substituting the value in the formula,

                 Density = 70 / 10

                 Density = 7 centimeter cube.

Therefore, the density of the given object will be 7 centimeter cube if  an object's mass is 70 g, and its volume is 10cm cubed.

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Answer:

Matching

6.D

7.A

8.C

9.B

Explanation:

Took test

103 °C, 90 °C, 101 °C Neither accurate nor precise, 100 °C, 99 °C, 100 °C are Precise, 105 °C, 106 °C, 105 °C are Both accurate and precise, 99 °C, 101 °C, 100 °C are Accurate. These are the correct set of measurements of the boiling point of water.

The melting point is defined as the temperature at which solid and liquid phases are at equilibrium state, whereas the boiling point is defined as the temperature at which the pressure of a vapor of a  liquid is equal to the external pressure.

Melting point in which the melting of solid occur to become a liquid at a given temperature, here the molecules gain enough amount of kinetic energy to get the intermolecular forces to convert into another form.

In case of Boiling point the liquid phase enters into the gaseous phase, when the external pressure is high than a temperature for the vapor pressure equal to the external pressure.

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Answer:

The answer to this question is approximately equal to 1.6 ×

[tex] 1.6 \times {10}^{23} atom \: o[/tex]

Answer:

i) b

ii) c

Explanation:

Please see attached picture for full solution.

Answer:

C is gaining 2 electrons

Explanation:

O has a 2- charge so for CO to pick up another O atom would add 2 more electrons.

Answer:

C gains 2 electrons

Explanation:

In the redox reaction, CO is changed into CO2 which means there is an additional oxygen. Oxygen loses 2 of its electrons in order to neutralize. So, C must be gaining 2 electrons in order to make the bond.

Answer:

Explanation:

                        N₂(g) + O₂(g) ⇄ 2NO( g )

We shall apply Le Chatelier's principle to see the effect of decrease in volume or increase in concentration on the effect of state of equilibrium in the reaction given .

In this reaction 1 volume of nitrogen gas reacts with 1 volume of oxygen to give 2 volume of NO gas . In total there is no change in volume due to reaction . So when we change the volume , the concentration of reactant and product will affect the rate of forward and reverse reaction . Overall there will be no change in the state of equilibrium . The equilibrium will neither shift to the right nor will shift to the left.

It will remain unchanged .

Answer:

the amount of fertilizer; x-axis

plant height; y-axis

Explanation:

The independent and dependent variables of Levi's experiment placed when graphed are the amount of fertilizer and the y-axis. Option B is correct.

The independent variables are those which are not dependent on other factors for their working or cannot be influenced by any other factor and the dependent variable is just the opposite of this one.

The experiment depends on the height of the plant but the fertilizer is independent of to work of the plant and fertilizer is independent and high and depends on other factors.

Therefore, Option B is correct. independent and dependent variables of Levi's experiment placed when graphed are the amount of fertilizer and the y-axis.

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Answer:

The independent variable effects the dependent variable.

Explanation:

The independent variable Is what you change whereas the dependent variable would change because of that.

for example, the indipendent variable could be how much you water a plant in ml each day, and the dependent variable would be how tall each plant grown]s with that water doseage per day.

Answer: [tex]1409.55[/tex]

Remove the 0's from each decimal number

[tex]3.7500 ---> 3.75\\9.7100 ---> 9.71[/tex]

Multiply

[tex]3.75*104=390\\9.71*105=1019.55[/tex]

Add

[tex]930+1019.55=1409.55[/tex]

Answer:

The mass of 3.491 × 10¹⁹ molecules of Cl₂  of Cl₂ is 4.11 × 10⁻³ grams

Explanation:

The number of particles in one mole of a substance id=s given by the Avogadro's number which is approximately 6.023 × 10²³ particles

Therefore, we have;

One mole of Cl₂ gas, which is a compound, contains 6.023 × 10²³ individual molecules of Cl₂

3.491 × 10¹⁹ molecules of Cl₂ is equivalent to (3.491 × 10¹⁹)/(6.023 × 10²³) = 5.796 × 10⁻⁵ moles of Cl₂

The mass of one mole of Cl₂ = 70.906 g/mol

The mass of 5.796 × 10⁻⁵ moles of Cl₂ = 70.906 × 5.796 × 10^(-5) = 4.11 × 10⁻³ grams

Therefore;

The mass of 3.491 × 10¹⁹ molecules of Cl₂  of Cl₂ = 4.11 × 10⁻³ grams.

Solid, Liquid, and Gas

Solid is the state in which matter maintains a fixed volume and shape; liquid is the state in which matter adapts to the shape of its container but varies only slightly in volume; and gas is the state in which matter expands to occupy the volume and shape of its container.

The states of matter are solid, liquid, and gas. Solid is the state in which matter maintains a fixed volume and shape; liquid is the state in which matter adjusts to the shape of its container but tends to vary only mildly in volume; and gas is the state in which matter expands to occupy the volume and shape of its container.

Matter would be any substance with mass and volume that occupies space.

Matter exists in three states: solid, liquid, and gas. The states of matter are solid, liquid, and gas.

Thus, above-mentioned are the three states of matter.

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Explanation:

The number of protons in the element C^12 (Carbon) is 6, number of electrons 12 and number of Neutrons is 6, same as the number of protons it contains

C^13 has 13 electrons, 6 protons and 7 Neutrons this one's neutron number is different from proton number because it's an isotope

Na^-1 has gained an electron so the number of electrons it has = 24 and the number of protons shown as 11 which means there are 23 - 11 = 12 Neutrons

O^-2 has gained two electrons and got 18 electrons in total, 8 protons and 8 neutrons

Answer:

The proportionality constant ( Henry’s constant) = 2.32 * 10^-5 M/kPa

Explanation:

Here in this question, we are concerned with calculating the proportionality constant for this gas.

Mathematically, we can get this from Henry law

From Henry law;

Concentration = Henry constant * partial pressure

Thus Henry constant = concentration/partial pressure

Henry constant = 0.00290 M/125 kPa = 2.32 * 10^-5 M/kPa

Answer:

Explanation:

given mass on earth =98 kg

gravitational pull on mars =3.711 m/s2

gravitational pull on venus =8.87 m/s2

weight of the body on mars =weight on earth/9.81 m/s2 *3.711 m/s2

W=98 kg*3.711 /9.81m/s2

W=37.07 kg

weight on the venus =weight on earth*8.87 m/s2 /9.81 m/s2

W= 98 kg*7.87 m/s2/9.81 m/s2

W=78.62 kg

Answer:

a 1) XZ2

2) YZ

3) X2

b 1) Ionic bond

2) Ionic bond

3) covalent bond

c) ionic compounds has high melting and boiling point

ionic compounds can conduct electicity in aqueous form

covalent compounds have electrons shared between the atoms

covalent compounds have lower melting point compared to ionic compound

Answer:

(i) XZ = Potassium Sulfide [K2SO4]

(ii) YZ = Potassium Chloride [KCI]

(iii) X = Sulfur [S]

b) (i) Ionic Bond. (ii) Ionic Bond. (iii) Covalent Bond.

c) (i) Ionic compounds have high melting and boiling points.

(ii) Ionic compounds can conduct electricity in a molten state or a solution as they have ions that can move and carry charge.

(iii) Covalent compounds have low melting and boiling points.

(iv) Covalent compounds can not conduct electricity as all electrons are involved in bonding so there are no free electrons or ions to carry the charge.

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Answer:

5.49

Explanation:

pH = - log[3.26 x 10-6] =5.49

Answer:

88

Explanation:

The ion has a charge of 2+, therefore the number of neutrons it possess is 86+2

which equals 88

The element X having a mass number of 230 and has 86 electrons is radium and has  142 neutrons.

An atom is composed basically of electrons, protons and neutrons. In a neutral atom, the number of protons and electrons are equal. The number of neutrons is the difference between the mass number and the number of protons (atomic number).

Since we know that the ion of the element X has 86 electrons and the compound formed is XBr2, it then means that neutral X has 88 electrons.

The number of electrons in the neutral atom is the same as the number of protons or atomic number. An element can be identified by its atomic number. The element having atomic number 88 is radium.

The number of neutrons is obtained as;

Mass number - atomic number

230 - 88 = 142 neutrons

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Answer:

it's option D

Answer:

Answer:

Potassium  (K)

Sodium  (Na)    

Calcium  (Ca)

Magnesium (Mg)  

Aluminium  (Al)

Iron  (Fe)  

Lead  (Pb)

Copper  (Cu)  

Silver  (Ag)

Gold  (Au)