why do we need to standardize EDTA in determination of water hardness?​

Answer:

100 HZ 1,000 HZ 10,000 HZ there you go :)

Answer:

100 hertz, 1,000 hertz, and 10,000 hertz

Explanation:

I took the k12 test :)

Answer:

b = 56.67 m

Explanation:

It is given that,

Area of the triangular field is 255 m²

We need to find the base of the field if its height is 9 m.

The area of a triangle is given by :

\(A=\dfrac{1}{2}\times b\times h\\\\b=\dfrac{2A}{h}\\\\b=\dfrac{2\times 255}{9}\\\\b=56.67\ m\)

So, the base of a triangle is 56.67 m.

Sodium dichromate is the empirical formula for the chemical.

An allotrope of carbon with the chemical formula carbon 6, benzotriyne or cyclo[6]carbon is a hypothetical molecule. Six carbon atoms form the molecule's ring, which is joined by alternating triple and single bonds.

We must identify the compound's simplest whole-number atom ratio in order to obtain the empirical formula. To begin, we can convert the masses of each element to moles as follows:

moles of sodium = 29.84 g / 22.99 g/mol = 1.299 mol

moles of creatinine = 67.49 g / 52.00 g/mol = 1.298 mol

moles of oxygen = 72.67 g / 16.00 g/mol = 4.542 mol

sodium.creatinine.oxygen = 1.299 mol / 1.298 mol : 1.298 mol / 1.298 mol : 4.542 mol / 1.298 mol

sodium.creatinine.oxygen = 1.001 : 1.001 : 3.500

sodium.creatinine.oxygen = 1001 : 1001 : 3500

sodium.creatinine.oxygen = 1001/GCF : 1001/GCF : 3500/GCF

sodium.creatinine.oxygen = 143 : 143 : 500.

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Answer:

dfdgfhgjghfdgsfdaafsgdhfjgkfjdgsasfdgfhghjgfdsafg

im 100% sure

Explanation:

The limiting reactant would be  H₂O.

The mass of the excess reactant would be 13.05 grams

Number of moles of P₂O5 = mass / molar mass

Number of moles of P₂O5 = 55 g / 141.88 g/mol

Number of moles of P₂O5 = 0.388 moles

Number of moles of H₂O = mass / molar mass

Number of moles of H₂O = 16 g / 18.02 g/mol

Number of moles of H₂O = 0.888 moles

Using the balanced chemical equation, we see that 1 mole of P₂O5 reacts with 3 moles of H₂O to produce 2 moles of H3PO4. Therefore, to react with all the P₂O5, we would need:

0.388 moles of P₂O5 × (3 moles of H₂O / 1 mole of P₂O5) = 1.164 moles of H₂O

Since we only have 0.888 moles of H₂O, it is the limiting reactant.

To determine the amount of excess P₂O5, we need to find how many moles of H₂O would be needed to react with all the P₂O5:

0.888 moles of H₂O × (1 mole of P₂O5 / 3 moles of H₂O) = 0.296 moles of P₂O5

The amount of excess P₂O5 is the initial moles of P₂O5 minus the moles of P₂O5 required to react with all the H₂O:

0.388 moles of P₂O5 - 0.296 moles of P₂O5 = 0.092 moles of excess P₂O5

Mass = 0.092 x 141.88 = 13.05 grams

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Answer:

88.63494750000001

Explanation:

Convert moles Gold to gram.

Chemical elements of chemical compounds help compensate substances, which are made up of one or more reactants (also known as reactants) and one or more products (also known as products).

Chemical synthesis, or, alternatively, chemical breakdown into two or more separate molecules, occurs when one material reacts with another to create a new substance.These processes are referred to as chemical reactions, and they are typically irreversible barring additional chemical reactions.

An alteration of one or more compounds as one or more unique and fresh substances is referred to as a chemical change or chemical reaction.In those other terms, a chemical is an atomic rearrangement-based chemical process.

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The value of ΔG at 25 °C for the given reaction is: ΔG = -370.4 kJ/mol + 0 = -370.4 kJ/mol So, the correct answer is -370.4 kJ/mol

To determine the value of ΔG (Gibbs free energy) at 25 °C for the given reaction:

25 (s, rhombic) + 3/2 \(O_2\)(g) → \(2SO_3\)(g)

We can use the equation:

ΔG = ΔG° + RT ln(Q)

where:

ΔG is the standard Gibbs free energy change

ΔG° is the standard Gibbs free energy change under standard conditions

R is the gas constant (8.314 J/(mol·K) or 0.008314 kJ/(mol·K))

T is the temperature in Kelvin (25 °C = 298 K)

Q is the reaction quotient, which is the ratio of the concentrations of the products to the concentrations of the reactants at a given point during the reaction.

Given that ΔG° is -370.4 kJ/mol, we can plug the values into the equation:

ΔG = -370.4 kJ/mol + (0.008314 kJ/(mol·K) * 298 K) * ln(Q)

Now, we need to determine the value of Q. Since all reactants and products are in their standard states, Q = 1, as their concentrations are taken to be 1.

ΔG = -370.4 kJ/mol + (0.008314 kJ/(mol·K) * 298 K) * ln(1)

Since ln(1) = 0, the term (0.008314 kJ/(mol·K) * 298 K) * ln(1) becomes 0.

Therefore, the value of ΔG at 25 °C for the given reaction is:

ΔG = -370.4 kJ/mol + 0 = -370.4 kJ/mol

So, the correct answer is -370.4 kJ/mol.

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Answer:

a. The Zn and HCl both retained their identity.

Answer:

i think its D

Explanation:

In order to get maximum accuracy, student should take average of results from all four trials.

Accuracy  in terms of chemistry can be defined as to how close a measurement is to the true value.There are three types of accuracy:

1) Point accuracy-It means accuracy is present at that point of scale only.It does not give any information about the accuracy of the instrument.

2)Percentage of true value--It is the accuracy  which is determined by identifying accuracy of the instrument  and comparing it with the measured true value.

3)Percentage of scale range- It is the accuracy  which determines accuracy of the measurement.

Accuracy in case of instruments  is neglected up  to ±0.5 percent.Accuracy of measurements can be increased by taking multiple measurements and taking into account human errors.

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Answer:1. metyletevinyl

4. (Z)-3-hydroxypropenal

Explanation:

Answer:

Graduated cylinder

Explanation:

A graduated cylinder is essentially meant for volume measurement. It is a cylinder that is graduated from zero to a certain number.

The graduated cylinder is gradually filled with water, the volume of water in the cylinder can be known by reading off the graduation on the cylinder, hence the answer above.

From the given data, the name of the hydrated salt would be  \(CoCl_2.83H_2O\).

The formula of the hydrated salt can be determined using the empirical formula approach. That is, we will find the mole equivalent of the anhydrous salt and the water of hydration and then combine them into a single formula after dividing by the smallest mole.

First, we need to determine the mass of the anhydrous salt and the water of hydration.

Mass of crucible (x) = 12.090 g

Mass of hydrated salt + crucible (y) = 16.250 g

Thus, the mass of the hydrated salt can be determined by subtracting x from y.

Mass of hydrated salt = 16.250 - 12.090 = 4.16 g

Mass of hydrate + crucible after evaporating off the water (z) = 12.424 g

Mass of anhydrous salt = z - x

                                      = 12.424 - 12.090

                                      = 0.334 g

Mass of water = 4.16 - 0.334

                        = 3.826 g

Now, let's find the moles:

Molar mass of \(CoCl_2\) = 129.839 g/mol

Molar mass of water = 18.01 g/mol

Mole of \(CoCl_2\) = 0.334/129.839 = 0.00257 mol

Mole of water = 3.826/18.01 = 0.2124 mol

Dividing through by the smallest mole

\(CoCl_2\) =  0.00257 / 0.00257  = 1

water = 0.2124/ 0.00257 = 83

Thus, the formula of the hydrate would be \(CoCl_2.83H_2O\)

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2 moles of ZnO are produced if 1 mole of Zn and 2 moles of \(O_2\) is required.

A mole is defined as 6.02214076 × \(10^{23}\) of some chemical unit, be it atoms, molecules, ions, or others. The mole is a convenient unit to use because of the great number of atoms, molecules, or others in any substance.

Balanced equation:

\(2 Zn + O_2\) → \(2 ZnO\)

For 2 moles of Zinc, we need 1 mol of Oxygen to produce 2 moles of Zinc oxide

For 1 mole Zn, we need 2 mol \(O_2\) to produce 2 moles ZnO only.

Hence, 2 moles ZnO is produced.

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Answer:

C = 4.60x10⁻⁵ M

Explanation:

The concentration of the compound can be calculated using Beer-Lambert Law:

\(A = \epsilon*C*l\)

Where:

A: is the absorbance of the ethanol = 0.58  

ε: is the molar absorptivity of the ethanol = 12600 M⁻¹cm⁻¹

C: is the concentration of the compound =?

l: is the optical path length = 1 cm

Hence, the concentration of the compound is:

\(C = \frac{A}{\epsilon*l} = \frac{0.58}{12600 M^{-1}cm^{-1}*1 cm} = 4.60 \cdot 10^{-5} M\)

Therefore, the concentration of the compound is 4.60x10⁻⁵ M.

I hope it helps you!

The given reaction is a double displacement reaction where, Cl and NO₃ group displaces between and sodium and silver atoms. The complete reaction is written as follows:

\(\rm NaCl (aq) + AgNO_{3} (aq) \rightarrow AgCl (s) + NaNO_{3} (aq)\).

There are various kinds of reactions classified based on the way of regrouping of atoms in the reactants.  In a double displacement reaction, two species from the reactant side are displaced of each other.

The reaction between sodium chloride and silver nitrate gives sodium nitrate in aqueous form and the precipitate of silver chloride. Here the groups nitrate and chlorine displaces between sodium and silver. Hence it is a double displacement reaction.

The net reaction represents the formation of the silver chloride precipitate.

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Answer:

Mn2+(aq) + 2H2O(l)  ⇒ MnO2(s) + 4H+(aq) + 2e-

Explanation:

Step 1: Data given

The oxidation number of manganese ion (Mn2+ ) is +2

The oxidation number of manganese dioxide  is +(MnO2)4

This means the oxidation number from Mn will go from +2 to +4, since it's increased, this is an oxidation reaction

Mn2+(aq)  ⇒ MnO2(s)

We have to balance both sides. Mn is already the same. But on the right side we have O atoms. T obalance both sides we have to add O atoms to the left side. This by adding 2x H2O

Mn2+(aq) + 2H2O(l)  ⇒ MnO2(s)

Now the amount of O atoms is balanced, but we have H- atoms at the left side. To balance we have to add 4 H atoms to the right side

Mn2+(aq) + 2H2O(l)  ⇒ MnO2(s) + 4H+(aq)

Now the amount of atoms is balanced at both sides. We also have to check if the charge on both sides is the same.

Since the left side has a charge of +2, and right has a charge of +4, we have to add 2 electrons to balance this.

Mn2+(aq) + 2H2O(l)  ⇒ MnO2(s) + 4H+(aq) + 2e-

Answer:

1.75 moles

Explanation:

According to CaC₂(s) + 2 H₂O(l) --> C₂H₂(g) + Ca(OH)₂(aq)

2 moles of H20 will produce 1 mole of Ca(OH)2

therefore 3.5 moles of H2O will produce 3.5 x (1/2) = 1.75 moles of Ca(OH)2

1 ×10^-6 M is the concentration of Vitamin C  in the resultant solution.

mass= 1000.0 mg =1 g

volume= 140.0 mL

concentration= moles of solute/ volume of solution

density= mass/volume

mass=density × volume

mass=1.00 g/mL× 140.0 m

mass=140

moles=140/1

moles= 140

concentration= moles of solute/ volume of solution

concentration= 140/ 140

concentration=1 M=1 ×10^-6 ppm

Concentration is the amount of a substance in a certain space. Another definition of concentration is the proportion of the solute to the solvent or whole solution. Typically, mass per unit volume is used to denote concentration. However, the solute concentration can also be expressed in volumetric or molecular units. Instead of using volume, concentration can be stated as a mass per unit. Despite the fact that chemical solutions are frequently employed to define concentration, it may be calculated for any combination.

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The pressure in the aerosol can is 3.47 atm.

First  we can use the ideal gas law:

PV = nRT

Where

First, we need to calculate the number of moles of propane in the can:

moles of C3H8 = mass of C3H8 / molar mass of C3H8

moles of C3H8 = 3.18 g / 44.1 g/mol = 0.072 mol

Next, we need to convert the volume of the can to liters:

V = 450 mL = 0.450 L

We also need to convert the temperature from Celsius to Kelvin:

T = 20°C + 273.15 = 293.15 K

The universal gas constant is R = 0.0821 L·atm/K·mol.

Now we can plug in the values and solve for P:

P = nRT / V

P = (0.072 mol) * (0.0821 L·atm/K·mol) * (293.15 K) / (0.450 L)

P = 3.47 atm

Therefore, the pressure in the aerosol can is 3.47 atm.

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Answer:

The ratio between the molecules dissolved in the solution (n = NaCl/KCl) is approximately 1.28.

Explanation:

To calculate the ratio between the molecules dissolved in the solution, we first need to determine the number of moles of each substance that is dissolved in the solution.

For KCl:

Molar mass of KCl = 39.1 g/mol (potassium) + 35.5 g/mol (chlorine) = 74.6 g/mol

Number of moles of KCl = mass of KCl / molar mass of KCl = 1 g / 74.6 g/mol = 0.0134 mol

For NaCl:

Molar mass of NaCl = 22.99 g/mol (sodium) + 35.5 g/mol (chlorine) = 58.5 g/mol

Number of moles of NaCl = mass of NaCl / molar mass of NaCl = 1 g / 58.5 g/mol = 0.0171 mol

The ratio between the molecules dissolved in the solution (n = NaCl/KCl) can be calculated by dividing the number of moles of NaCl by the number of moles of KCl:

n = 0.0171 mol / 0.0134 mol = 1.28

Answer:

Solute is Pottasium Nitrate and Solvent is Water.

Explanation:

ANSWER

Mass in kg = 2,403.9475 kg

STEP-BY-STEP EXPLANATION:

Given information

From the question provided, you are asked to convert 2.650 tons to kilograms

Let x be the mass converted in kg

Recall that, 1 ton is equivalent to 907.15kg according to the Standard International unit

Therefore, we have 2,403.9475kg in 2.650 tons

The mass of the silver block, given that it was initially at 55.1 °C  and is submerged into 100.0 g of water at 25.0°C is 189.8 g

We'll begin our calculation by obtaining the heat absorbed by the water. Details below:

Q = MCΔT

Q = 100 × 4.184 × 2.9

Q = 1213.36 J

Finally, we shall determine the mass of the silver block. Details below:

Q = MCΔT

-1213.36 = M × 0.235 × -27.2

-1213.36 = M × -6.392

Divide both sides by -6.392

M = -1213.36 / -6.392

M = 189.8 g

Thus, we can conclude that the mass of the silver block is 189.8 g

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Complete question:

A silver block, initially at 55.1∘C, is submerged into 100.0 g of water at 25.0∘C in an insulated container. The final temperature of the mixture upon reaching thermal equilibrium is 27.9∘C. The specific heat capacities for water and silver are Cs,water = 4.18J/(g⋅∘C) and Cs, silver = 0.235J/(g⋅∘C). What is the mass of the silver block?

Answer:

B.

Explanation:

A chemical bond holds together attractions of atoms