In the lab, a student adds 4.5 g of sodium chloride (NaCl) to 100.0 g of water. Calculate the molality of the solution.

Answer:

Molarity and molality are both used to express the concentration of a solution. The amount of solute is both expressed in moles.

Explanation:

Answer:

molecular formula of liquid = C₈H₁₈

Explanation:

First we determine the empirical formula of the liquid:

Number of moles of each element present in the liquid = % mass / molar mass

For Carbon, (molar mass = 12.01 g/mol) : 84.2/12.01 =7.011 moles

For Hydrogen (molar mass = 1.01 g/mol) : 15.8/1.01 = 15.643

Simplest mole ratio of the elements, C : H  is given by:

C = 7.011/7.011 = 1.0

H = 15.643/7.011 = 2.23

Multiplying through with 5, C:H = 5:11

Therefore, empirical formula is C₅H₁₁

The molecular mass of the liquid is next determined:

Using PV = nRT to find the number of moles of the liquid present

P = 5.0 atm; V = 568.0 mL = 0.568 L; R = 0.082 L*atmmol⁻¹ K⁻¹; T = 273 + 120 = 393 K

n = PV/RT = (5*0.568)/0.082*393

n = 0.088 moles

Molar mass of liquid = mass/no of moles = 10.0 g/ 0.088 moles = 113.63 gmol⁻¹

Molecular formula = n(empirical formula)

Molar mass of empirical formula, C₅H₁₁ = 71 gmol⁻¹

n = molecular mass/empirical mass = 113.63/71 = 1.6

Therefore, molecular formula =  1.6*(C₅H₁₁) = C₈H₁₈

Answer:

47

Explanation:

Silver (Ag), chemical element, a white lustrous metal valued for its decorative beauty and electrical conductivity. Silver is located in Group 11 (Ib) and Period 5 of the periodic table

The atomic number of silver is 47.

That also means that silver has 47 electrons and 47 protons.

The atomic mass of silver is 108u.

107 - 47 = 60

Silver has 60 neutrons.

Answer:

Galileo: "Father of Modern Science."

Aristotle: Geocentric theory." (The planests revolves around the earth.)

Torricelli: Invented the barometer. (An instrument which measures pressure.)

Copernicus: Heliocentric theory. (Aka, the planets revolves around the sun.)

Vesalius: Examined the inner workings of the human body

Newton: Developed law of universal gravitation.

Nightingale: Founded nursing profession.

Celsius: Developed metric temperature scale

I hope this helps! Thanks:)

Answer:2

Explanation:

Answer:

2

Explanation:

Answer:

Hydrogen in its metallic state (usually considered a nonmetal)​

Lithium.

Sodium.

Potassium.

Rubidium.

Cesium.

Francium.

Explanation:

Answer:

The list of elements that contains only metals is tin, copper and cesium.

Carbon and iodine aren't metals.

Helium isn't metal.

Neither iodine, carbon, nor argon are metals.  

(Hope this helps) Sky

Answer:

burning is a rapid process, rustig is a slow process. burning releases light during the process,rusting does not. burning can speed up with addition of more external conditions, rusting cannot be sped up greately by addition of external materials. burning results in release of large amts of heat, rusting very little amt of heat

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and most brainlest

-Rust happens when something is unpolished and is old. Burning has been modified by heat.

-Burning is a chemical change. Rust is a physical change.

-Burning something cannot be fixed back to its natural form, while when something is rusted it can possibly be re-used and fixed.

-The texture of something burnt is usually fragile and brittle while rust makes (metal for example) gritty.

-Rust usually forms solely on metals while almost anything can be burned.

note: you asked for 4 answers but i gave you 5 in case you didnt like any of them. Hope this helps!

Answer:

I know the answer to 5, i think

Explanation:

Explanation:

Copper(II) carbonate basic, CuCO3•Cu(OH)2(s), is the dull green colour that forms on copper roofs. Copper oxidises in the air to form an approximately equimolar mixture of CuCO3 and Cu(OH)2.The percentage of CuCO3 in the

Answer:

A. C(s) + O2(g) → CO2(g) + 393.5 kJ

Explanation:

The formation of carbon IV oxide (CO2) is an exothermic process. n exothermic process is a chemical process in which heat is evolved. Speaking in lay man's terminology, heat is one of the 'products' of the reaction. This implies that heat is evolved by the process.

The formation of CO2 is always a combustion reaction where heat is evolved or released by the reaction system. Hence the reaction could be shown as;

C(s) + O2(g) → CO2(g) + 393.5 kJ

This implies that 393.5 kJ of energy is released in the reaction in the form of heat. Hence the answer given in the answer box.

Answer: C(s) + O2(g) → CO2(g) + 393.5 kJ

Answer:

gasoline

Explanation:

Answer: See below

Explanation:

1. To calculate the mass, you know you can convert by using molar mass. Since mass is in grams, we can use molar mass to convert moles to grams. This calls for the Ideal Gas Law.

Ideal Gas Law: PV=nRT

We manipulate the equation so that we are solving for moles, then convert moles to grams.

n=PV/RT

P= 100 kPa

V= 0.831 L

R= 8.31 kPa*L/mol*K

T= 27°C+273= 300 K

Now that we have our values listed, we can plug in to find moles.

[tex]n=\frac{(100kPa)(0.831L)}{(8.31kPa*l/molK)(300K)}[/tex]

[tex]n=0.033mol[/tex]

We use the molar mass of NO₂ to find grams.

[tex]0.033mol*\frac{46.005g}{1mol }=1.52 g[/tex]

The mass is 1.52 g.

2. To calculate the temperature, we need to use the Ideal Gas Law.

Ideal Gas Law: PV=nRT

We can manipulate the equation so that we are solving for temperature.

T=PV/nR

P= 700.0 kPa

V= 33.2 L

R= 8.31 kPa*L/mol*K

n= 70 mol

Now that we have our values, we can plug in and solve for temperature.

[tex]T=\frac{(700kPa)(33.2L)}{(70mol)(8.31 kPa*L/molK)}[/tex]

[tex]T=40K[/tex]

The temperature is 40 K.

Answer:

C8H16

Explanation:

First thing to do here is to calculate the molar mass of the compound

Mathematically;

molar mass = mass/number of moles

we can calculate the number of moles using the ideal gas equation

Mathematically;

PV = nRT

n = PV/RT

where p is the pressure at 5 atm

V is the volume at 568 ml = 568/1000 = 0.568 L

R is the molar gas constant which is 0.0821

T is the temperature which is 120+ 273 = 393k

Inserting these values into the equation, we have

n = (5 * 0.568)/(0.0821 * 393)

n = 0.088 moles

So the molar mass = 10/0.088

= 114 g/mol

Now let’s go to the percentages

C = 84.2/12 = 7.016666666666667

H = 15.8/1 = 15.8

divide by the smallest

C = 7.016666666666667/7.016666666666667 = 1

H = 15.8/7.016666666666667 = 2 approximately

The empirical formula is CH2

So for the molecular formula, we have;

(12 + 2)n = 114

14n = 114

n = 114/14 = approximately 8

So the molecular formula of the liquid will be (CH2)n = C8H16

Answer:

5010J

Explanation:

The following data were obtained from the question:

Mass (m) = 15g

Heat of fusion (ΔHf) = 334J/g

Heat required (Q) =..?

The heat energy required to melt the ice can be obtained as follow:

Q = m·ΔHf

Q = 15 x 334

Q = 5010J

Therefore, the heat energy required to melt the ice is 5010J.

Answer:

THE NEW VOLUME AT A PRESSURE OF 0.775 atm AND TEMPERATURE OF 18 °C IS 0.397 L

Explanation:

Using the combined gas equation

P1V1/T1 = P2V2/ T2

P1 = 1 atm

VI = 315 mL = 315 / 1000 L = 0.315 L

T1 = 25°C  25 + 273 K = 298 K

P2 = 0.775 atm

T2 = 18 °C = 18 + 273 K = 291 K

V2 = Unknown

Substituting the values into the equation, we obtain:

V2 = P1V1 T2/ P2 T1

V2 = 1 * 0.315 * 291 / 0.775 * 298

V2 = 91.665 / 230.95

V2 = 0.3969 L

The new volume at the given change in conditions is 0.397 L

In a galvanic cell, the oxidation and reduction of metals occurs at the electrodes. There are two electrodes in a very cell, one in each half-cell. The cathode is where reduction takes place and oxidation takes place at the anode.

Answer:

B

Explanation:

its an acidic oxide, it disolves in water to form carbonic acid which is an acid

Answer: Environmental bias can be defined as the idea that suggests a group of people being living in the environment which is harmful for them.

Explanation:

There are three categories that make up the environmental bias there are socio-cultural choice, occupational choice, and personal choice.

The environmental bias can be related to chemistry as chemical lab is an area prone to chemical (acid, alkali) and fire so produced in reactions thus prone to accidental hazards not safe for working of people. But people like to work in chemical lab due to their personal and occupational choice.

Answer:

4

Explanation:

Answer:

Explanation:

A battery

Answer:

Ac motor is in this images

Answer:

B

Explanation:

The molecular formula for pentyne is C5H8

Answer:

calculate grams and use mole ratio lol

Explanation:

Answer:

Explanation:

23

Answer:

C) Liquids and gases

Explanation:

The correct answer would be liquids and gases.

The molecules of liquids and gases move randomly when held in a container. The random movement causes a collision between the molecules of the liquids/gases and between the walls of the container, creating pressure in the process. This is unlike the molecules of solids that vibrate about fixed positions.

Hence, the correct option is C.

Answer:

There are light absorbing color bodies called chromophores that are present in dyes. Ultraviolet rays are one of the causes of fading because they can break down chemical bonds and fade the color in objects.

Answer:

2.5 g of platinum

Explanation:

Recall that a catalyst is a specie added to a reaction system to increase the rate of reaction. A catalyst does not participate in the chemical reaction hence it remains unchanged at the end of the chemical reaction. A catalyst merely provides an alternative reaction pathway by lowering the activation energy of the reaction system. Hence a catalysed reaction usually proceeds faster with less energy requirement than the uncatalysed reaction.

Since the catalyst does not participate in the reactions and remains unchanged at the end of the reaction, the mass of platinum will remain the same (2.5g). The mass can only change if a specie participates in the chemical reaction. Hence the answer.

2.5 g of platinum will there be left in the vessel at the end of the reaction

The following information should be considered:

learn more: https://brainly.com/question/2514933?referrer=searchResults

Answer:

It is decreasing the temperature of the reactant mixture.

Explanation:

Just took the test

In order to decrease the number of collisions and energy of reactant molecules, the temperature of the reactant mixture would need to be decreased as well.

The temperature of reactants is proportional to the average kinetic energy of the molecules of the reactants.

Also, the higher the average kinetic energy of the reactant molecules, the higher their chances of colliding and reacting to form products.

Thus, in order to decrease their energy and collision frequency, the temperature of the reactant mixture needs to be decreased.

More on temperature and kinetic energy can be found here: https://brainly.com/question/2731193

Answer:

fddff s

Explanation:

v c dggbgzfx