Determine the number of moles in a sample of 2.82g B

Answer:c

=

0.0253 M

Explanation:

Molarity is a measure of a solution's concentration in terms of how many moles of solute it contains per liter of solution.

So, in essence, if you have the number of moles of solute, like you do here, and the total volume of the solution expressed in liters, you can find how many moles of solute you get per liter, i.e. the molarity of the solution.

Keeping in mind the fact that the moles of solute are distributed evenly in any given volume of the solution, you can say that because  

7.98 L

of solution contain  

0.202

moles of solute, which in your case is potassium chloride,  

KCl

,  

1 L

of this solution will contain

1

L

⋅

0.202 moles KCl

7.98

L

=

0.0253 moles KCl

So, if your solution contains  

0.0253

moles of potassium chloride per liter, it follows that its molarity is equal to

c

=

0.0253 M

Here  

M

is equivalent to  

mol/L

, or molar.

The molarity of the solution that contains 0.505 mol KCl in 7.98 L of the solution is 0.0632 moles/L.

Molarity is a measure of a solution concentration in terms of how many moles of solute it contains per liter of solution.

Molarity = Moles of solute / Liters of solution

Its unit is mole/L

Given that a solution contains 0.505 mol KCl in 7.98 L of solution

Moles of solute (KCl) = 0.505 mol

Liters of solution = 7.98 L

Then, the molarity will be

M = [tex]\frac{0.505}{7.98}[/tex]

   = 0.0632 moles/L

Therefore, the molarity of the given solution is 0.0632 moles/L.

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Answer:

1)

Explanation:

ok this is a write answer

Answer:

H2O is the name of this molecule and it is water

Answer:

different from the number of their neutrons

Explanation:

They each have one single proton (Z = 1), but differ in the number of their neutrons. Hydrogen has no neutron, deuterium has one, and tritium has two neutrons. ... Their nuclear symbols are therefore 1H, 2H, and 3H. The atoms of these isotopes have one electron to balance the charge of the one proton.

The reaction between copper II chloride and sodium sulfide as well as lead II nitrate and potassium sulfate both produce precipitates.

The solubility of a substance in water is in accordance with the solubility rules.  It is possible that a solid product may be formed when two aqueous solutions are mixed together. That solid product is referred to as a precipitate.

Now, we will consider each reaction individually to decode whether or not a precipitate is possible.

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Answer:

I don't know the answer sorry man

Answer:K2X

Explanation: Valency can be defined as the combining power of an element. It is the valency that dictates the value an element will have when writing a chemical formula for its compound.

MgX is a compound of magnesium and an element X. The valency of magnesium in most of its compound is +2. Now for the 2 to have been absent in the chemical formula, this shows that the element X itself have a valency if -2 for the valencies of both to have canceled out.

Now considering the element potassium, it is an alkaline metal belonging to group 1 of the periodic table. Hence, it is expected that it has a valency of +1

Forming a compound with element X means there would be an exchange of valencies between the two. We have established that x has a valency of -2. The formula of the compound thus formed by exchanging the valencies of both element would be K2X

The chemical formula for the compound formed between Lithium and element X is Li₂X.

Valency can be described as the combining power of a chemical element. It is the valency that describes the value an element will have in the chemical formula for that compound.

MgX compound is a compound of magnesium and an element X. The valency of magnesium is +2.  The chemical formula shows that the element X itself has a valency of -2 which gave a neutral compound.

Now given element is Lithium, it is an alkali metal of group 1 of the periodic table. It has a valency of +1 as it has one electron in its valence shell.

Forming a compound with element X, there will be an exchange of valencies between the two. As element X has a valency of -2. The formula of the formed compound by exchanging the valencies of Lithium and element X would be Li₂X

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Cobalt-60 is comprised of 27 protons, 33 neutrons, and 27 electrons. Nuclear reactors are used to artificially create it.

A radioactive isotope containing cobalt with something like a half-life of 5.2713 centuries is called cobalt-60 (60Co). Nuclear reactors are used to artificially create it. Neutron irradiation of bulk material of the monoisotopic as well as mononuclidic cobalt element 59 Co is necessary for deliberate industrial manufacture.

The accidentally generated 60 Co in the latter instance (inside the absence of additional cobalt) is mostly the product of many phases involving neutron activation on iron isotopes inside the reactor. Cobalt-60 is comprised of 27 protons, 33 neutrons, and 27 electrons.

Therefore,  cobalt-60 is comprised of 27 protons, 33 neutrons, and 27 electrons.

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Answer:

methanol because it is liquid at room temperature which means that it melts at a lower temperature

Silicon dioxide is a solid at room temperature and methanol is a liquid. Silicon dioxide has a higher melting point than methanol because silicon dioxide is solid, and with increasing temperature, it will melt.

Melting point is that point or temperature at which the solid items are converted into liquid, and it changes their atoms and the atoms lose their compactness.

Here, two compounds are given, Silicon dioxide and methanol, the first one is solid at room temperature, so it will need more temperature to melt down and methanol is still liquid at room temperature, so its melting point is low.

Thus, methanol is a liquid while silicon dioxide is a solid at ambient temperature. Because silicon dioxide is a solid and melts at greater temperatures, it has a higher melting point than methanol.

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Answer:

4

Explanation:

water would be produced from 4 molecules of methane (CH4) reacting with 8 molecules of oxygen (O2)

The products of the combustion of hydrocarbon are 4 molecules of carbon dioxide and 8 molecules of water.

A combustion reaction can be described as a reaction that produces fire and takes place at a high temperature. It is an exothermic reaction as well as a redox reaction that usually takes place between a fuel and mostly oxygen gas.

Examples of Combustion Reactions such as during the combustion of 4 molecules of methane reacting with 8 molecules of oxygen gas to give carbon dioxide and two molecules of water.

[tex]4CH_4 + 8O_2\longrightarrow 8H_2O + 4CO_2[/tex]

Oxygen is the essential reactant for combustion because the combustion is not possible in the absence of oxygen. Complete combustion takes place when a fuel burns completely to produce heat with oxygen and carbon dioxide.

The burning of wood fuels in the presence of air is an example of combustion. The carbon present in wood reacts with oxygen gas in the air to liberate heat and form gaseous products.

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Answer:

Francium bc it has the largest atomic radius

Francium has the greatest atomic radius. Despite being a highly radioactive metal with a short half-life, francium has little environmental impact.

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Answer:

join id(8606512121) pas(12345)

#5

At 22min the temperature is at 40°C

#6

Graph ended at 20°C so condetion occured at 20°C

#7

After 70°C the matter got melted do its at liquid state

Answer:

c

Explanation:

oxygen is lost electrons are added in oxidation state is decreased

Answer:

the correct answer is C

hope this helps <3

the answer is is is is is is is is is is is is is is

Answer:

Answer Below! : )

Explanation:

Groundwater is stored in the tiny open spaces between rock and sand, soil, and gravel. How well loosely arranged rock (such as sand and gravel) holds water depends on the size of the rock particles.

Hope this helps! : )

Answer:

Underground  brainliest plz

Explanation:

Answer:

C) Bromine

Explanation:  Bromine needs just one electron to fill its outer shell.

Bromine has the greatest attraction for electrons in a covalent bond because it has the highest electronegativity among the given option as it needs only one electron to complete its octet. Therefore, option (C) is correct.

Halogens are the elements of group 7 of the modern periodic table, which contains five elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).

Halogens are generally nonmetals in which fluorine and chlorine are gases at room temperature and bromine is a liquid, iodine and astatine are solids. Halogens are very reactive as they have seven valence electrons and need only one electron to get a noble gas configuration.

As we move left to right in a period the electronegativity increases and all the given elements Se, As, Br and Kr are elements of the same period but the Kr is a noble gas. Therefore, Bromine has the greatest attraction for electrons in a covalent bond.

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Answer:

density=20/8 g/cc=2.5 g/cc

Mercury is more dense, so aluminum will float on it. Water is less dense, so the aluminum will be below water.

Aluminum will float atop mercury because it is more dense than it. Due to water's lower density, the metal will lie below the surface.

Density is defined as the measure of how densely a material is packed together.

It can also be defined as the mass of a solid substance per unit volume.

Density is important because it enables us to predict which compounds will float and which will sink in a liquid, density is a crucial notion. As long as an object's density is lower than the liquid's density, it will often float.

The term "density" refers to the relationship between a substance's mass and the volume it takes up in space. The mass, size, and arrangement of an object's atoms influence its density.

Density can be expressed as

Density = mass / volume

There are two types of density.

Thus, aluminum will float atop mercury because it is more dense than it. Due to water's lower density, the metal will lie below the surface.

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Answer:

C) 2CO + O₂ →   2CO₂

Explanation:

The equation C is correct.

2CO + O₂ →   2CO₂

This equation have four oxygen atom and two carbon atoms on both side of equation. So it is correctly balanced.

All others are incorrect:

A) CO + O₂ →   CO₂

this is incorrect because there are three oxygen atoms on left while two atoms on right.

B) CO + 2O₂ →   2CO₂

this is incorrect because there are five oxygen atoms on left while four atoms on right.

D)  2CO + 2O₂ →   2CO₂

this is incorrect because there are six oxygen atoms on left while four atoms on right.

The answer is B.

Back-side attack by water at the more substituted carbon.

You can follow the steps.

Step1: Electrophilic attack forms a bromonium ion intermediates.

Step2: Back-side attack by water at the more substituted carbon opens the bromonium ion intermediates.

Step3: H2O removes a proton from the intermediates.

Answer:

I believe that would be methane! I hope this helps you!

Answer:

methane

Explanation:

The largest component of natural gas is methane, a compound with one carbon atom and four hydrogen atoms (CH4). Natural gas also contains smaller amounts of natural gas liquids (NGL, which are also hydrocarbon gas liquids), and nonhydrocarbon gases, such as carbon dioxide and water vapor.The main component in natural gas is methane. It also has ethane, propane, butane, hydrocarbons.

Carbon and oxygen atoms in (CH3)2C=O form sigma and pi bonds. The pi bonds are formed using unhybridized p orbitals.

Acetone (CH3)2C=O contains the carbonyl group (C=O). Carbon is bonded to oxygen via a double bond as shown in the orbital structure. The carbon atom is also bonded to two methyl groups.

The central carbon  atom is sp2 hybridized as well as the oxygen atom in acetone. The pi bond is formed by the overlap of unhybridized p orbitals on both carbon and oxygen atoms. The sigma bonds are formed using the sp2 hybridized carbon atoms on carbon and oxygen.

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The final temperature in the calorimeter, with a heat capacity of 2.70 kcal/°C, internal energy for the combustion of cyclohexanol (C₆H₁₂O) of -890.7 kcal/mol and initial temperature of 27°C, is 29.33 °C.

We can find the final temperature of the water in the calorimeter with the following equation:

[tex]\Delta E = -C\Delta T = -C(T_{f} - T_{i})[/tex]    (1)

Where:

ΔE: is the change in internal energy for the combustion of C₆H₁₂O = -890.7 Kcal/mol

C: is the heat capacity of the calorimeter = 2.70 Kcal/°C

[tex]T_{f}[/tex]: is the final temperature =?

[tex]T_{i}[/tex]: is the initial temperature = 27 °C

By solving equation (1) for [tex]T_{f}[/tex], we have:

[tex] T_{f} = -\frac{\Delta E}{C} + T_{i} [/tex]

[tex]T_{f} = -\frac{-890.7 \frac{kcal}{mol\: C_{6}H_{12}O}*\frac{1 mol \: C_{6}H_{12}O}{100.158 g \: C_{6}H_{12}O}*0.708 g \: C_{6}H_{12}O}{2.70 kcal/^{\circ}C} + 27 ^{\circ}C = 29.33 ^{\circ}C[/tex]  

Therefore, the final temperature of the water is 29.33 °C.

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Answer:

B

Explanation:

equilibrium happens when two things are in complete balance and thermal is in reference to heat so two things are in thermal equilibrium once they have the same temperature.

The option which indicates that two objects are in thermal equilibrium is the objects that have the same temperature. Thus, the correct option for this question is B.

Thermal equilibrium may be defined as a state of a system in which all the parts of the system occupy the same temperature. Two or more objects are in thermal equilibrium if there is no net flow of thermal energy or heat between them when they are considerably connected by a path permeable to heat.

The mechanism of thermal equilibrium occurs when a cup of hot coffee is put on the table and after a short period of time, the temperature of the coffee is the same as the surrounding temperature. So, this represents an example of thermal equilibrium.

Therefore, the correct option for this question is B.

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Answer:

Seven methods were used to assess water quality in the river system. These methods included single-factor assessment, water quality grading, comprehensive pollution index, the Nemerow pollution index, principle component analysis, fuzzy comprehensive evaluation, and comprehensive water quality identification index.

Answer:

Volume is the amount of space an object takes up. I hope this helps you! :D