Why is crystal of oxalic acid regarded as a primary standard solution ?

Step-by-step explanation:

Assuming a basis of 100 grams

composition of Potassium = 44.2%

composition of potassium = 0.442

mass of potassium = 0.442 x 100g

Mass of potassium= 44.2 grams

mole of potassium = reacting mass / molar mass

Molar mass of potassium = 39.1 gram/ mol

Mole of potassium = 44.2 / 39.1

Mole of potassium = 1.13 moles

mole of potassium chloride + mole of potassium nitrate = mole of potassium

n(KCL) + n(KNO3) = n(k)

since mole (n) = m/M.M

Then we have,

m(KCL)/M.M(KCL) + m(KNO3)/M.M (KNO3) = 1.13

M.M (KCL) = 39.1 + 35.5

M.M (KCL) = 74.6 gram/mol

M.M (KNO3) = 39.1 + 14 + 3(16)

M.M (KNO3) = 39.1 + 14 + 48

M.M (KNO3) = 101.1 gram/mol

Let the mass of KCL be x

Let the mass of KNO3 be y

Assuming the total mass of the mixture is 100g

x + y = 100 ---------- equation 1

x/74.6 + y/101.1 = 1.13 ---- equation 2

From the first equation, make x the subject of the formula

x = 100 - y

100- y / 74.6 + y/101.1 = 1.1.3

1.355(100 - y) + y = 1.13 * 101.1

135.52 - 1.355y + y = 114.243

Collect the like terms

-1.355y - y = 114.243 - 135.52

-0.355y = -21.277

Divide both sides by -0.355

-0.355y/-0.355 = -21.277/-0.355

y = 59.9grams

y is 60 grams approximately

Recall, y is the mass of KNO3

From the first equation

x + y = 100

Answer:

23.4 milliliters

Explanation:

Note 1: This answer assumes that the volume of CuNO3 is negligible
Note 2: CuNO3 can't be produced in any meaningful quantities and can't be obtained by the average chemist, maybe you meant Cu(NO3)2 instead?

From the definition of molarity, molarity = moles / volume
the number of moles is the number of grams divided by the molar mass, or
2.47 divided by 125.55 which is 0.01967

The M and moles is known so volume can be found.

0.82 = 0.01967 / volume
0.82 * volume = 0.01967
volume = 0.01967 / 0.82 = 0.023988 liters = 23.4 milliliters

ANSWER

The amount of valence electron in an atom is equivalent to the group the atom is located

EXPLANATION

Valency is define as the combining power of an element. Valence electrons are electrons located at the outer most shell of an element.

Valence electrons tell us the group a particular element belongs to and also the chemical properties of the element.

For example, sodium atom

Sodium has the below electronic configuration

The structure above represents a sodium atom. The structure contains a single electron at the outer most shell of the atom. The single electron is called the valence electron of sodium. Hence, sodium belongs to group 1

Therefore, the amount of valence electron in an atom is equivalent to the group the atom is located

Explanation:

Because during the phase transformation the pressure inside the closed container remains the same and that's a fact ay

Answer:D

Explanation:

The equilibrium partial pressure of D is 0.362atm.

2A(g) + B(s) <==> 2C(s) + D(g)

The pressure that a gas, in a mixture of gases, would exert if it alone occupied the whole volume occupied by the mixture is called partial pressure of the gas.

In the equilibrium expression, we ignore solids as they are considered to have a value of unity. Thus, we can write the equilibrium expression for the above reaction as:

K = (PD) / (PA)²

where, K = Partial pressure equilibrium

           PD = Partial pressure of gas D

           PA = Partial pressure of gas A

Kp = 8210

PA = 0.021 atm

8210 = PD / (0.021)²

PD = 8210 × (0.021)²

PD = 0.362 atm.

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Answer:  The correct answer is C. Zn

Explanation:  Zn in its native state has bonds between multiple cations and a sea of valance electrons.

The balanced equation for the reaction above is: 2Mg(s) + O₂(g) = 2MgO(s).

To balance a chemical reaction or equation, it simply means to make sure the total number of atoms of elements on the reactants side of the equation equals or is the same as the number of atoms in product side.

From the task given above, to balance the equation in the reaction between magnesium and oxygen to give the product, magnesium oxide:

Mg(s) + O₂(g) = MgO(s)

Since there are 2 oxygen atoms in reaction side and 1 oxygen atom at the product side, you'll add 2 to the product (MgO) so we can have the same number of oxygen atoms as the reactant side and complete it by adding 2 also to magnesium in the product side:

2Mg(s) + O₂(g) = 2MgO(s

So therefore, having the same atom numbers in both reactants and products side is the only way to balance chemical equation.

Complete question:

Balance the chemical reaction below:

___Mg(s) + ___O₂(g) ____MgO(s)?

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The enthalpy of the reaction is obtained as -430.22 kJ/mol

The enthalpy change refers to the energy that is lost or gained in the reaction. Let us now look at the standard enthalpies of formation of the reactants and the products.

Standard enthalpy of formation of gaseous  water = -241.82 kJ/mol

Standard  enthalpy of formation of gaseous carbon dioxide = -393.5 kJ/mol

Standard  enthalpy of formation of gaseous methanol = -205.10 kJ/mol

Standard  enthalpy of formation of gaseous oxygen = 0 kJ/mol

Hence;

Using the formula;

Enthalpy of formation of the products - Enthalpy of formation of the reactants

ΔH = [(-393.5 ) + (-241.82)] - [(-205.10) + 0]

ΔH = (-635.32) + 205.10

ΔH = -430.22 kJ/mol

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The incorrect name-formula combination is FeCIO₄ -  Iron(I) perchlorate; option B.

The IUPAC nomenclature of naming compounds refers to the convention of naming compounds using the oxidation states of the elements present in the compound.

The IUPAC nomenclature of the given compounds is given below as follows:

A. Co(CIO₂)₂ - Cobalt(II) chlorite; the oxidation state of cobalt is +2

B. FeCIO₄ -  Iron(I) perchlorate; the formula of the compound is wrong because iron does not exist in the +1 state

C)Mn(CIO4)₂ -  Manganese(II) perchlorate;  the oxidation state of manganes is +2

D) Cr(CIO)₃​ - Chromium(III) hypochlorite ;  the oxidation state of chromium is +3

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Armondo could test how curves in a river affect the speed of the river as the speed of the water outside of a bend increases as a river rounds the bend. The water's velocity, however, diminishes as it approaches the interior of the curve.

A fantastic illustration of how water can alter the contour of the land is a meandering river. A river seldom turns when it is bordered by sheer rock, but it will do so when it opens up in broad valleys. Water will flow more swiftly and destroy the ground faster outside the river. Over time, it will curve too much and slow down.

To simulate a meandering river, use a stream table. The speed of the water outside of a bend increases as a river rounds the bend. The water's velocity, however, diminishes as it approaches the interior of the curve. A bar of deposited silt, like this one, is created as a result of the reduction in velocity.

The velocity of a river is the rate at which water flows through its course. Numerous elements, such as the channel's form, the slope's grade, the amount of water carried by the river, and the amount of friction brought on by jagged edges in the riverbed, all affect a river's speed.

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Answer:

For every action, there is opposite and equal reaction

1)

Na3PO4 + H2SO4 => Na2SO4 + H3PO4

We must have the same number of atoms on both sides.

We start with Na,

2 Na3PO4 + H2SO4 =>3 Na2SO4 + H3PO4 (6 Na on both sides)

Then we proceed with P,

2 Na3PO4 + H2SO4 =>3 Na2SO4 +2 H3PO4 (2 P on both sides)

After that, we continue with S,

2 Na3PO4 + 3 H2SO4 =>3 Na2SO4 +2 H3PO4 (3 S)

The number of H and O are solved.

Answer: 2 Na3PO4 + 3 H2SO4 =>3 Na2SO4 +2 H3PO4

The enthalpy of the reaction is -164 kJ/mol.

We know that the reaction that occurs between the chromium metal and the acid is an exothermic reaction thus there is an increase in the temperature of the system.

Number of moles of the silver nitrate solution is obtained from;

Volume * concentration

500/1000 L * 0.915 M = 0.46 moles

We can now assume that the density of the solution is 1 g/mL hence the mass of the solution is 500g. Let the specific heat capacity of the solution be 4.18 J/Kg/°C.

Then;

H = mcdT

H = Heat lost in the reaction

m = mass of the solution

c = specific heat capacity

dT = temperature change

H = 500 * 4.12 * ( 55.9 - 19.3)

= 75.4 kJ

The heat of reaction = 75.4 kJ/0.46 moles

= -164 kJ/mol

Let us recall that the negative simply means that heat was lost in the reaction.

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Answer:

the oxidation number of N in (NH4)2CrO4 is -3. the oxidation number of O in (NH4)2CrO4 is -2. the oxidation number of Cr in (NH4)2CrO4 is +6. the oxidation number of H in (NH4)2CrO4 is +1

hope i helped <3

N has an oxidation number of -3, O has an oxidation number of -2, and Cr has an oxidation number of +6 in the compound (NH4)2CrO4.  The H in (NH4)2CrO4 has an oxidation number of 1

Oxidation number is defined as how many electrons a given atom or ion has either gained or lost when compared to a neutral atom. Any free element's oxidation number is always zero. The meaning was expanded to cover additional reactions in which electrons are lost, regardless of whether oxygen was present, since the substance loses electrons when it is oxidized.

In the case of a monatomic ion, the oxidation number is always the same as the ion's charge.  The name of the compound is ammonium chromate which has oxidation number both in positive as well as negative charge electrons.

Thus, N has an oxidation number of -3, O has an oxidation number of -2, and Cr has an oxidation number of +6 in the compound (NH4)2CrO4.  The H in (NH4)2CrO4 has an oxidation number of 1.

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Acidic solution I use: Lemon Juice (Citric acid)

I know this is acidic because it is sour in taste just like all other acids.

Basic solution I use: Handwash

I know this is basic because it is soapy and slippery in nature, and it dissolves oil and grease.

Neutral solution I use: Water

I know this is neutral because it has equal number of H+ and OH- ions.

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The pH of the 1.63 M solution of methylamine is 10.56.

The pH of the 1.63 M solution of methylamine is calculated from the equation of the dissociation reaction  as follows:

H₃CNH₂ (aq) + H₂O (l) ---> H₃CNH₃ (aq) + OH⁻ (aq)

pKb of H₃CNH₂ = 3.66

Kb of H₃CNH₂ = 10⁻³°⁶⁶ = 2.19 * 10⁻⁴

The [OH¯] is calculated using the Kb expression:

Kb = [OH⁻] * [H⁺] / [HA}

[OH⁻] = [H⁺] = x

Kb = x² / (1.63 - x)

Assuming is x <<< 1.63, x is negligible and the denominator = 1.63

x = √(2.19 * 10⁻⁴ x 10⁻¹¹ * 1.63)

x = 3.57 * 10⁻⁴

pOH = -log (3.57 * 10⁻⁴)

pOH = 3.44

pH = 14 - 3.44

pH = 10.56

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Because amount has no effect on mass percentages, the mass percentage of carbon in 5, 50, and 500 g of sucrose is 42.1  %

The mass:
It also represents the body's inertia, or resistance to acceleration (change in velocity) when a net force is applied. The mass of an object dictates the strength of its gravitational attraction to other bodies.

The kilogram is the SI base unit of mass (kg). Mass is not the same as weight in physics, despite the fact that mass is frequently calculated by measuring the object's weight using a spring scale rather than a balance scale and comparing it directly with known masses. Because of the reduced gravity, an object on the Moon would weigh less than it does on Earth, yet it would still have the same mass.

Molecular formula of sucrose is C12 H22 O11

Molar mass of Sucrose , C12 H22 O11 is = ( 12 x 12 ) + ( 22 x 1 ) + ( 11 x 16 )   g/mol

                                                                = 342 g/mol

The molar mass of Carbon is 12 g/mol

342 g of C12 H22 O11  contains 12 x 12 g of C

5 g of C12 H22 O11  contains Y g of C

Y = ( 12x12x 5 ) / 342

  = 2.105  g of  C

mass % of C = (mass of C / mass of sucrose ) x 100

                    = (2.105 / 5 ) x 100

                    = 42.1  %

342 g of C12 H22 O11  contains 12 x 12 g of C

50.0 g of C12 H22 O11  contains Y g of C

Y = ( 12x12x 50 ) / 342

  = 21.05  g of  C

mass % of C = (mass of C / mass of sucrose ) x 100

                    = (21.05 / 50 ) x 100

                    = 42.1  %

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Since the number is 5.8*10^-3 g, the negative symbol in front of the power of 3 means that there are 3 0's in front of the real number, in standard notation, therefore we will add these 3 zeros to the number

0.0058 grams, and if we multiply it by 1000 we will end up with 5.8 mg, letter C

The order of the liquids will depend on the density of each of them. The densest will go to the bottom of the container, the least dense will be on top.

Let's see what the density of each of the substances is, let's assume that we are at room temperature.

Ice density = 0.917g/cm^3

Corn oil density =0.925g/cm^3

Ethanol density = 0.789g/cm^3

The order of density from lowest to highest is:

Ethanol < Ice < Corn oil

This will be the order from top to bottom, so the answer will be:

B. ethanol, ice, corn oil C

According to this question, a graduated cylinder contains 25.8 mL of water. 2 glass marbles weighing 6.5 g was dropped into the cylinder. The new water level reads 27.2 mL.

This means that the volume of the marbles can be calculated as follows:

27.2mL - 25.8mL = 1.4mL

The volume of the marbles is 1.4mL.

Density is a measure of the mass of matter contained by a unit volume. The density can be calculated by dividing the mass by the volume as follows:

Density = 6.5g ÷ 1.4mL = 4.64g/mL

The density of the marble is 4.64g/mL.

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The no. Of moles of carbon is found to be 7.5×10⁻⁴.

No. of moles are give by = Given mass/molar mass.

Given mass is 0.009g and the molar mass of carbon atom is 12g.

So, the no. Of moles are given by ,

No. Of moles = 0.009/12

= 0.00075 = 7.5×10⁻⁴mol.

The value of 6.023 x 10²³ is equal to one mole of any substance (Avogadro number). It can be used to quantify the chemical reaction’s by-products. The symbol for the unit is mol.

Carbon element is insoluble in water, diluted acids and bases, as well as organic solvents, carbon is an inert material. It combines with oxygen at high temperatures to generate carbon monoxide or dioxide. Diamond and graphite are two distinct allotropes, crystalline forms of the carbon atom.

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The balanced equation is

We need the molar mass of each compound.

• The molar mass of Hg(NO3)2 is 324.7 g/mol.

• The molar mass of Na2Cr2O7 is 261.97 g/mol.

• The molar mass of HgCr2O7 is 416.58 g/mol.

• The molar mass of 2Na(NO3) is 169.99 g/mol.

Then, we find the number of moles of each reactant.

• Moles of Hg(NO3)2 = 24.68g ÷ 324.7 g/mol = 0.076 mol.

• Moles of Na2Cr2O7 = 7.41g ÷ 261.97 g/mol = 0.028 mol.

According to equation 1 mole of Hg(NO3)2 will react with 1 mole of Na2Cr2O7, which means 0.076 mol of Hg(NO3)2 has to react with 0.076 mol Na2Cr2O7, which is not possible because there are not enough moles to get 0.076 of Na2Cr2O7 in the reaction. Hence, Na2Cr2O7 is the limiting reactant and Hg(NO3)2 is the excess reactant.

Then, subtract the number of moles to obtain the excess:

The remaining moles from Hg(NO3)2 are: 0.076mol - 0.028 = 0.048 mol.

Therefore, the remaining excess reactant is 0.048 moles.

But, we need to transform it to grams using the molar mass of Hg(NO3)2.

Therefore, the remaining mass of Hg(NO3)2. is 15.59 grams.

Answer:

B

Explanation:

The molecular equation of the reaction of copper chloride and aqueous silver nitrate:

CuCl₂ (aq)  + 2 AgNO₃ (aq)  →   Cu(NO₃)₂ (aq)  +  2AgCl (s)  

The net ionic equation will be:

2Ag⁺(aq) +  2Cl⁻(aq) → 2AgCl(s)  

The net ionic equation can be described as an equation that represents only those elements, compounds, or ions that directly participated in that particular chemical reaction.

The balanced chemical equation reaction of copper chloride and aqueous silver nitrate:

CuCl₂ (aq)  + 2 AgNO₃ (aq)  →   Cu(NO₃)₂ (aq)  +  2AgCl (s)  

The complete ionic equation for the reaction can be represented as follows:

Cu²⁺(aq) + 2Cl⁻(aq) +  2Ag⁺(aq) + 2NO₃⁻ →  Cu²⁺ (aq) + 2NO₃⁻(aq) + 2AgCl(s)  

In the ionic equation, the copper and nitrate ions appear unchanged on both sides of the equation. When we mix the two solutions, the copper and nitrate ions do not participate in the reaction. So copper and nitrate ions can be eliminated from the ionic equation.

2Ag⁺(aq) +  2Cl⁻(aq) → 2AgCl(s)  

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The arrangement of the in order of decreasing atomic size is as follows:

The atomic size of an atom is the diameter of the atom and is calculated as half the distance between the nuclei of two covalently-bonded nuclei of the atom.

The atomic size of elements increases down a group but decreases across a period.

The reason for this trend is that, on going down a group, an extra electron shell is added to the element below. However, across a period, the electron shell remains the same whereas the size of the positive nuclear charge increases, therefore, the atomic size of atoms in the same period decreases from left to right across the period.

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Complete question:

Arrange the following elements in order of decreasing atomic size.

Rank the atoms from the largest to smallest. To rank items as equivalent, overlap them: Al, Cl, Ar, P, and K.

The amount of heat energy needed to increase a substance's temperature by 1°C per unit mass is known as its specific heat capacity (or 1K). joule per kilogram per kelvin is the SI unit (Jkg-1K-1).

so,

805,560 Joules heat energy is needed to raise the temperature  from 23 °C to 191 °C.

Use the formula:

Q = cMΔT

where

Q = heat energy needed for that material to get desired temperature change (in Joules)

M = mass (in grams) so you have to convert from kilograms.

c = specific heat constant for the material being heated [in /(grams oC)]

ΔT = change in temperature (in oC)

Q = (1.75)(2.74 x 1000)(191 - 23) = (1.75)(2740)(168) = 805,560 Joules

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Q = cMΔT

where

Q is the amount of heat energy required to change the material's temperature.

You must convert from kilograms since M is mass (in grams).

c = the material's specific heat constant [in grams per degree Celsius]

T stands for temperature change (in oC)

Q is equal to (1.75 x 2.17 x 1000) (191 - 23) = (1.75 x 2170 x 168) = 637,980 Joules.

What does "specific heat capacity" mean?

In thermodynamics, a substance's specific heat capacity, commonly referred to as massic heat capacity, is calculated by dividing its heat capacity by its mass in a sample.

particular heat capacity's mathematical formula?

Delta T = Q=mc

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ANSWER

The mass of glucose in grams is 230 grams

EXPLANATION

Given information

The total volume of the solution = 1.5L

Follow the steps below to find the mass of glucose

Step 1: Convert the volume of the solution from L to mL

According to the standard conversion, 1L is equivalent to 1000mL

Let x represents the volume of the solution in mL

Hence, the volume of the solution in mL is 1500mL

Step 2: Find the mass of the glucose in grams

Hence, the mass of glucose in grams is 229.5 grams

To know the molarity of carbonic acid when titrated with ammonium hydroxide. We use [tex]M_{1} V_{1} =M_{2} V_{2}[/tex] formula and hence the molarity of carbonic acid is 0.063M.

Titration is an experimental technique in which the molarity of unknown solution is calculated using other solution whose molarity is known. To know the end point we use phenolphthalein as indicator.  

Mathematically,

[tex]M_{1} V_{1} =M_{2} V_{2}[/tex]

where,

[tex]M_{1}[/tex]=Molarity of carbonic acid

[tex]M_{2}[/tex]=Molarity of  ammonium hydroxide

[tex]V_{1}[/tex]=Volume of  carbonic acid

[tex]V_{2}[/tex]=Volume of  ammonium hydroxide

Substituting all values

[tex]M_{1}[/tex]=(0.125×23.8)÷47.00

[tex]M_{1}[/tex]=0.063M

Thus the molarity of  carbonic acid is 0.063M

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Answer:  dinophyte

Explanation: its a type of protist. it is unicellular and has chloroplasts

Scientists discover a species that is unicellular and has chloroplasts.  It could be a dinophyte.

A single-celled eukaryotic group (Protists) called a dinophyte makes up the phylum Dinoflagellates. They possess chloroplasts and are single-celled.

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