Will give brainliest to correct answer of this picture:

Answer:

0.847 molecule.

Explanation:

From the question given above, the following data were obtained:

Mass of X₄Z₃ = 3.93×10¯²² g

Number of molecules of X₄Z₃ =?

Avogadro's number = 6.022×10²³ molecules

Next, we shall determine the molar mass of X₄Z₃. This can be obtained as follow:

Molar mass of X₄Z₃ = (4×59.45) + (3×13.84)

= 237.8 + 41.52

= 279.32 g/mol

Finally, we shall determine the number of molecules in 3.93×10¯²² g of X₄Z₃. This can be obtained as follow:

From Avogadro's hypothesis,

1 mole of X₄Z₃ = 6.022×10²³ molecules

But 1 mole of X₄Z₃ = 279.32 g

Thus we can say that:

279.32 g = 6.022×10²³ molecules

Therefore,

3.93×10¯²² g = 3.93×10¯²² × 6.022×10²³ / 279.32

3.93×10¯²² g = 0.847 molecule.

Thus, 3.93×10¯²² g of X₄Z₃ contains 0.847 molecule.

Answer:

any gas takes up 22.4L per mole so 2.4*22.4=53.76

Explanation:

In 2.4 moles at STP, 53.79 litres of N2 gas are present.

Moles are defined as the amount of substance of a system that contain the same number of entities as the number of atoms in 12g of carbon 12.

STP is defined as the standard temperature and pressure. At STP, as system has s temperature of zero degree centigrade or 273 Kelvin and the pressure is 1 atm.

PV= nRT

P= 1 atm

V= ?

n= 2.4 moles

R= 0.0821 L atm /K/mol

1 x V = 2.4 x 0.0821 x 273

V = 53.79 litres

Hence, 53.79 litres of N2 gas is present in 2.4 moles at STP.

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Answer:

P = 0.0166 mm Hg

Explanation:

To solve this question, we need to use the Clausius Clapeyron equation, which is a commonly used expression to calculate vapour pressure at a given temperature. We have the enthalpy of vaporization of the mercury, so, let's write the equation:

Clausius Clapeyron equation:

Ln (P₂ / P₁) = (-ΔHv / R)(1/T₂ - 1/T₁)    (1)

Where:

R: universal constant of gases (8.314 J / K.mol)

P₂: Vapour pressure at 43°C (or 316 K)

P₁: Pressure of mercury at the boiling point (1 atm)

T₂: temperature at 43 °C

T₁: Boiling point of mercury (357 °C or 630 K)

As we are given the boiling point of the mercury, we can safely assume that the pressure at this point is 1 atm, becuase remember that when a sustance boils, is because it's internal pressure has reached the atmospherical pressure of 1 atm. With this clear, all we just need to do is solve for P₂. We are going to do this very slowly so you can understand the process. First let's replace the given data:

Ln (P₂ / 1) = (-59100 J/mol / 8.314 J / K.mol) (1/316 - 1/630)

Ln P₂ = -7108.49 * (3.16x10⁻³ - 1.59x10⁻³)

Ln P₂ = -7108.49 * (1.51x10⁻³)

Ln P₂ = -10.7338

P₂ = 10⁽⁻¹⁰°⁷³³⁸⁾

P₂ = 2.18x10⁻⁵ atm

We can express this value in mm Hg and it will be:

P₂ = 2.18x10⁻⁵ * 760

Hope this helps

Answer:

hydrogen

Explanation:

In electrolysis of water, gas evolved at cathode is hydrogen

indicator, hope this helps :

Answer:

B

Explanation:

Because that's what is being changed into a different color.

Answer: C ) The reactants are higher in energy than the products

Explanation:

The enthalpy that is a state variable that identifies the content of heat. Then the change of enthalpy for the exothermic reactions is negative, meaning that the energy of the products is lower than the energy of the reactants.

Answer:

44.84 ml

Explanation:

14.86

+

15.0

+

14.980

_______

44.84

Answer: A: Has little to no reaction; might turn slightly red in color. B: The liquid grows darker in color to a more reddish tone.

Explanation: I didn’t have the necessary materials to complete the experiment so the teacher told me and I put it in my own words.

Answer:

68.1% is percent yield of the reaction

Explanation:

The reaction of methane with oxygen is:

CH₄ + 2O₂ → CO₂ + 2H₂O

Where 2 moles of oxygen react per mole of CH₄

Percent yield is:

Actual yield (28.2g CO₂) / Theoretical yield * 100

To solve this question we need to find theoretical yield finding limiting reactant :

Moles CH₄:

15.1g CH₄ * (1mol / 16.04g) = 0.9414 moles

Moles O₂:

81.2g * (1mol / 32g) = 2.54 moles

For a complete reaction of 0.9414 moles of CH₄ are needed:

0.9414 moles CH₄ * (2 mol O₂ / 1mol CH₄) = 1.88 moles of O₂. As there are 2.54 moles, O₂ is in excess and CH₄ is limiting reactant

In theoretical yield, the moles of methane added = Moles of CO₂ produced. That is 0.9414 moles CO₂. In grams = Theoretical yield:

0.9414 moles CO₂ * (44.01g / mol) = 41.43g CO₂

Percent yield: 28.2g CO₂ / 41.43g CO₂ * 100=

Answer:

32 days.

Explanation:

First we determine how much is made in a day.

16.50 x 4 = 66.

Next, we divide 2100 by 66 to reach our amount of days needed.

2100 / 66 = 31.818181... [81 is what repeats over and over.]

We round this up to the nearest whole number. You can't underpay, so you have to round.

The next whole number would be 32, so our answer is 32 days.

Answer:

1. False 2.True3.True? Unsure

Explanation:

Answer:

215.9 cm

Explanation:

1 foot= 30.5cm

30.5cm times 7 1/12=215.9cm

The given height of David is 7 ft, 1.0 inch, so in centimeters, the height will be 216.4 cm.

A conversion factor is a number that is used to multiply or divide one set of units into another. When converting to an equal value, the appropriate conversion factor must be used.

We must convert one unit to another in order to achieve accuracy and avoid measurement confusion.

We do not, for example, measure the length of a pencil in kilometers. In this case, one must convert kilometers (km) to centimeters (cm) (cm).

To convert feet to centimeters, multiply the given foot length by 30.48 cm.

So,

Height in cm will be = 7.1 x 30.48

Height in cm = 216.4cm

Thus, the height of David in centimeters is 216.4 cm.

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Answer:

What is ^ for?

Explanation:

Answer:

Boiling Water

Explanation:

Boiling water is an example of physical change and not and not a chemical change because the water vapor still has the same molecular structure as liquid water.If the bubbles were caused by the decomposition of a molecule into gas then boiling would be a chemical change.

Answer:

A chemical change results from a chemical reaction, while a physical change is when matter changes forms but not chemical identity. Examples of chemical changes are burning, cooking, rusting, and rotting. Examples of physical changes are boiling, melting, freezing, and shredding

Explanation:

The food has 23629.64 cal

Given

mass = 1000 g of water

temperature increases 23.65 * C

Required

The energy of the food

Solution

Heat absorbed by water :

Q = m . c . Δt

Q = 1000 g x 4.184 J/g°C x 23.65 °C

Q = 98951.6 J

1 Joules = 0.2388 Calories

98951.6 J = 23629.64 cal

Answer:

90 mV

Explanation:

Faraday constant, F = 96487

Gas constant, R = 8.314

Number of mole of electron transferred, Z = 2

MgCl in solution A, = 0.1 mm

MgCl in solution A, = 100 mm

Using the relation :

E=(RT/ZF) In(Mg out/Mgin)

E = (8.314*298) / (2*96485) * In(100/0.1)

E = (2477.572 / 192970) * 6.9077552

E = 0.0128391 * 6.9077552

E = 0.0886897 V

E = 88.68 mV (approximately 90 mV)

Answer:

[tex]k_2=2.46[/tex]

Explanation:

Hello!

In this case, according to the Arrhenius equation for variable temperature:

[tex]ln(\frac{k_2}{k_1} )=-\frac{Ea}{R}(\frac{1}{T_2} -\frac{1}{T_1} )[/tex]

Given the temperatures to be computed in kelvins and the activation energy, we obtain:

[tex]ln(\frac{k_2}{0.924} )=-\frac{89800J/mol}{8.314J/(mol*K)}(\frac{1}{306.45K} -\frac{1}{298.15K} )\\\\ln(\frac{k_2}{0.924} )=0.981\\\\k_2=0.924*exp(0.981)\\\\k_2=2.46[/tex]

Best regards!

Answer:

Measure the volume of water poured into a graduated cylinder, then place the object in the water and remeasure the volume. The difference between the two volume measurements is the volume of the object. Now simply divide the mass by the volume to calculate the density of the object.

Answer:

Hope this help you

Explanation:

The answer is 261.3368. We assume you are converting between grams Barium Nitrate and mole. You can view more details on each measurement unit: molecular weight of Barium Nitrate or mol The molecular formula for Barium Nitrate is Ba(NO3)2.

Answer:

0.382

Explanation:

Answer:

369 ml

Explanation:

Mass of Aluminium (Al) = 20 g

Molar concentration =  2.007M

Molar concentration = Number of moles / Volume

The relationship between mass and number of moles;

Number of moles = Mass / Molar mass

Number of moles = 20 / 27 = 0.741 mol

2.007  = 0.741  / Volume

Volume = 0.741 / 2.007 = 0.369 L

converting to millilitres by multiplying by 1000

Volume = 0.369 * 1000 = 369 ml

Answer:

Density, d = 5.96 g/mL

Explanation:

Given that,

Mass, m = 105 g

Volume, V = 17.6 mL

We need to find the density of the substance. So,

[tex]d=\dfrac{m}{V}\\\\d=\dfrac{105\ g}{17.6\ mL}\\\\d=5.96\ g/mL[/tex]

So, the density of the substance is 5.96 g/mL.

Answer:

Covalent-network (also called atomic) solids—Made up of atoms connected by covalent bonds; the intermolecular forces are covalent bonds as well. Characterized as being very hard with very high melting points and being poor conductors. Examples of this type of solid are diamond and graphite, and the fullerenes.

I hope it's helpful!

Answer:

network solid

Explanation:

Answer:

0.292 g/mL.

Explanation:

From the question given above, the following data were obtained:

Mass of object = 28.1 g

Volume of object = 96.2 mL

Density of object =..?

Density of an object is simply defined as the mass of the object per unit volume of the object. Mathematically, it can be expressed as:

Density = mass / volume

With the above formula, we can obtain the density of the object as follow:

Mass of object = 28.1 g

Volume of object = 96.2 mL

Density of object =..?

Density = mass / volume

Density = 28.1 / 96.2

Density of object = 0.292 g/mL

Thus the density of the object is 0.292 g/mL

Answer: 1075.5 mph

Explanation:anything moving at 4.78*10^4 cm/sec

equivalent to

cm —> miles = 1/1.6*10^5

sec —> hr = 1/3600

[4.78*10^4]*3600/1.6*10^5 = 1075.5 mph

Answer:

i wish i know

Explanation:

i wish i know