What is the [OH−] in 0.20 M sodium cyanate, NaOCN, solution?
a. 3.7 × 10−7 M
b. 4.6 × 10−7 M
c. 5.5 × 10−7 M
d. 2.4 × 10−6 M
e. 8.7 × 10−7 M

Answer:

A is its answer

Explanation:

Fan uses electrical energy and makes it to mechanical energy by rotating

Same is with the drill

Trampoline does not use electrical energy

Lamp uses electrical energy but it converts it into light energy and heat energy

So A is the answer

Two isotopes of rubidium occur naturally, rubidium 85 (84.91 amu) at 72.17 % and rubidium 87 (86.91 amu) at 27.83 %. The atomic mass of rubidium is 85.468 μ.

To find the atomic mas of rubidium -

Determining the average atomic mass of an element, we take the average weight of the atomic masses of the naturally occurring isotopes. This means that all the isotopes together are calculated by multiplying the atomic mass and the percentage of abundance. So we have a sum of all the different isotopes ( which is 100 % of abundance)

For naturally occurring rubidium, there are 2 isotopes.

mass of Rb-85 x abundance + mass of Rb-87 x abundance -

84.9118 x 0.7217 + 86.9092 x 0.2783 = 85.46767642 = 85.468 μ

On the periodic table, we can see for Rubidium

85.468 μ which is the average atomic mass of Rubidium and also for its two naturally occurring isotopes.

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The boiling temperature of bromine is 331.29 K

Explanation:

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

Br₂ (l) —> Br₂(g)

Enthalpy change (ΔH) = 30.91 KJ/mol

Entropy change (ΔS) = 93.3 J/mol·K

Next, we shall convert 30.91 KJ/mol to J/mol. This can be obtained as follow:

1 KJ/mol = 1000 J/mol

Therefore,

30.91 KJ/mol = 30.91 × 1000

30.91 KJ/mol = 30910 J/mol

Thus, 30.91 KJ/mol is equivalent to 30910 J/mol.

Finally, we shall determine the boiling temperature of bromine. This can be obtained as follow:

Enthalpy change (ΔH) = 30910 J/mol

Entropy change (ΔS) = 93.3 J/mol·K

ΔS = ΔH / T

93.3 = 30910 / T

Cross multiply

93.3 × T = 30910

Divide both side by 93.3

T = 30910 / 93.3

T = 331.29 K

Thus, the boiling temperature of bromine is 331.29 K

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Hypotonic, hypertonic, and isotonic are terms used to describe the concentration of solutes in a solution compared to the concentration of solutes in a cell or another solution.

Hypotonic solutions have a lower osmolarity (concentration of solutes) compared to the inside of a cell. When a cell is placed in a hypotonic solution, water will flow into the cell in an attempt to equalize the concentrations. This causes the cell to swell and potentially burst. Hypotonic solutions are commonly used in medical settings to hydrate patients and replenish fluid loss.

Hypertonic solutions have a higher osmolarity compared to the inside of a cell. When a cell is placed in a hypertonic solution, water will flow out of the cell, causing it to shrink. Hypertonic solutions are often used to draw excess fluid out of swollen tissues or to dehydrate and preserve food.

Isotonic solutions have the same osmolarity as the inside of a cell. When a cell is placed in an isotonic solution, there is no net movement of water. Isotonic solutions are frequently used in medical treatments, such as intravenous fluids, to maintain proper fluid balance and prevent cell damage.

In summary, hypotonic solutions have a lower solute concentration, hypertonic solutions have a higher solute concentration, and isotonic solutions have an equal solute concentration compared to the inside of a cell.

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Answer:

The correct answer is 1.66 atm ≅ 1.7 atm

Explanation:

Given:

T₁ = -13°C + 273 = 260 K (initial temperature)

T₂ = 15°C + 273 = 288 K (final temperature)

P₁ = 1.5 atm

P₂= ?

We use the mathematical expression of Gay Lussac's Law to calculate P₂, as follows:

P₁/T₁ = P₂/T₂

P₂= P₁/T₁ x T₂ = (1.5 atm)/(260 K) x 288 K = 1.66 atm ≅ 1.7 atm

Since the law says that the temperature of a gas is directly proportional to the pressure, when the temperature is increased, the pressure increases.

Answer:

3846g of Carbon tetrachloride is in the chemical equation.

Explanation:

The Balanced equation is :

   CH4 + 4CL2 -> CCL4 + 4HCL

Converting grams to moles ;

  Moles of CL2 = Mass / Molar mass

  Molles of CL2 = 709.0g/70.906g/mol => 10 moles

  Moles  of CCL4 = Moles of CL2 / 4

  Moles of CCL4 = 10 moles/ 4 => 2.5 moles

Converting moles of CCL4 to grams:

 Mass of CCL4 = Moles of CCL4 x Molar mass of CCL4

 Mass of CCL4 = 2.5 moles x 153.823 g/mol => 384.5575 grams

Therefore 384.6 grams of carbon tetrachloride can be produced from reacting 709.0 grams of chlorine.

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Answer:

0.342 moles

145 moles

0.0239 moles

0.498 moles

Explanation:

To solve this you only need to follow this rule:

N = n x Na. For solving this questions, you just need to divide this values for Avogadro's Coasting, and it's done. Hope it helped!

Titration is the best investigation to identify an unknown liquid as acidic, basic, or neutral by measuring its pH level.

A student finds an unlabeled bottle of liquid under his kitchen sink. Titration is the investigation that would best help him identify the unknown liquid as acidic, basic, or neutral.

Titration is the chemical method used to find the amount of acid or base in a given substance. This method is a laboratory technique used to measure the concentration of a known solution (the titrant) with a solution of an unknown concentration (the analyte).

The unknown solution is slowly added to the known solution until it reacts completely, allowing us to calculate the concentration of the unknown solution. Titration may be used to identify an unknown solution as acidic, neutral, or basic by determining its pH level. It's a highly precise technique that's often used in analytical chemistry laboratories to measure the concentration of chemicals.

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Answer:

D

Explanation:

To find the compressibility factor (Z) of CO₂ gas at a pressure (P) of 27 bar and a temperature (T) of 2 °C, we need to use the ideal gas law and the Redlich-Kwong equation of state. From this, the approximate compressibility factor (Z) of CO₂ gas at a pressure of 27 bar and a temperature of 2 °C is approximately 0.123.

First, let's convert the temperature from Celsius to Kelvin:

T = 2 + 273.15 = 275.15 K

Next, we need to calculate the values of a and b for CO₂ using the Redlich-Kwong equation:

a = 0.42748 × (R² × Tc^2.5) / Pc

a = 0.42748 × (8.314² × 304.2^2.5) / 73.8

a ≈ 0.3658 bar × (L/mol)^2 × K^0.5

b = 0.08664 × (R × Tc) / Pc

= 0.08664 × (8.314 × 304.2) / 73.8

≈ 0.0351 L/mol

Now, we can calculate the compressibility factor (Z) using the Redlich-Kwong equation:

Z = P / (R × T) - (a / (sqrt(T) × (V - b)))

= (27 × 10⁵) / (8.314 × 275.15) - (0.3658 / (sqrt(275.15) × (V - 0.0351)))

Solving for Z requires knowing the molar volume (V) of CO₂, which we don't have. However, we can approximate the compressibility factor assuming ideal gas behavior:

Z ≈ P / (R × T)

= (27 × 10⁵) / (8.314 × 275.15)

≈ 0.123

Therefore, the approximate compressibility factor (Z) of CO2 gas at a pressure of 27 bar and a temperature of 2 °C is approximately 0.123.

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Based on the provided information, the number of grams of carbon should you end with is 5g.

If you start with 5 grams of carbon on the reactant side, the grams of carbon you should end with 5g based on the law of conservation of mass. The law of conservation of mass, also known as principle of mass conservation postulate that for any system closed to all transfers of matter and energy, the system mass must remain constant over time, as the mass of system cannot change, so quantity can neither be added nor be removed. Hence, the law states that mass is neither created nor destroyed in a chemical reaction. Hence, the grams of reactants that one starts with, one will end with the same amount. Chemicals recombine to give a different compound in the product, the mass is still always conserved.

Note: The question is incomplete. The complete question probably is: If you start with 5 grams of carbon on the reactant side, how many grams of carbon should you end with?

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Answer:

See explanation below

Explanation:

Sodium will react with chlorine to form sodium chloride NaCl.

Na is a group I metal with 1 valance electron to become one Na+ ion to bond with one Cl- ion

Magnesium will also react with chlorine to form magnesium chloride MgCl2

Mg is a group II metal with 2 valence electrons become one Mg2+ ion to bond with two Cl- ions.

Both Na and Mg are metals while Cl is non-metals so the bond between metal and non-metal is ionic bond.

Hope this helps.

Answer:

Explanation:

a )

PbS      +     2PbO   →     3Pb    +     SO₂

                  2 mole       3 moles       1 moles

b )

2 moles of PbO is required to produce 3 moles of Pb

17 moles of PbO is required to produce 3/2 x 17 moles of Pb

= 3/2 x 17 moles of Pb

= 25.5 moles of Pb .

c )

1 mole of  SO₂ needs 2 moles of PbO

27.3 mole of  SO₂ needs 2 x 27.3  moles of PbO

PbO needed = 2 x 27.3 moles

= 54.6 moles .

d )

PbS      +     2PbO   →     3Pb    +     SO₂

1 mole       2 mole    

1 mole  of  PbS requires 2 moles of PbO

17.6 mole  of  PbS requires 2 x 17.6  moles of PbO

PbO required = 2 x 17.6 moles

= 35.2 moles .

PbO available = 36 moles . So PbO is in excess .

Hence PbS is the limiting reagent .

The volume that is occupied by the gas is obtained as  56 L.

We know that from the Avogadro's law, the volume that can be occupied by one mole of a gas is obtained as 22.4 L. This implies that we have to find the number of moles in the 70 g of the CO and then obtain the corresponding volume by simple proportion.

Number of moles of CO = 70.0 g/28 g/mol

= 2.5 moles

If 1 mole of the gas occupies 22.4 L

2.5 moles of the gas occupies 2.5 * 22.4/1 mole

= 56 L

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Answer:

E conduct electricity when melted

Explanation:

They can not produce electricity until dissolved/ melted in water

To determine the pH of a solution using a pH indicator paper, you need a color chart or a color scale that corresponds to different pH values.

This color chart or scale is used to compare the color of the pH indicator paper after it has been immersed in the solution. The pH indicator paper is impregnated with a universal pH indicator, which is a chemical compound that changes color depending on the acidity or alkalinity of the solution.

The indicator undergoes a chemical reaction with the hydrogen ions (H+) or hydroxide ions (OH-) present in the solution, resulting in a color change.

By comparing the color of the pH indicator paper with the color chart or scale, you can determine the approximate pH of the solution. The color chart usually provides a range of colors corresponding to different pH values, allowing you to match the observed color to the nearest pH value.

In the hypothesis mentioned, the aim is to calibrate a cabbage pH indicator using the pH values obtained from a universal pH indicator. Therefore, in addition to the pH indicator paper and color chart, you would also need a range of solutions with known pH values to establish a calibration curve specific to the cabbage pH indicator.

In summary, to determine the pH of a solution using a pH indicator paper, you need a color chart or scale that correlates the observed color of the pH indicator paper with different pH values. This chart or scale serves as a reference for interpreting the color change and determining the pH of the solution.

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Answer: COLOR KEY

Explanation: CS

An element is the sum of protons and neutrons in an atom

An element is a fundamental thing that is difficult to divide into smaller parts. A substance that cannot be broken down by non-nuclear reactions is referred to as an element in chemistry and physics. An element is a unique component of a bigger system or set in computing and mathematics.

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According to Charle's law, the volume of the given mass of a gas is directly proportional to its absolute temperature provided that the pressure is constant. Mathemically;

where;

V1 and V2 are the initial and final volume of the gas

T1 and T2 are the initial and final temperatures of the gas (in Kelvin)

Given the following parameters:

Substitute the given parameters into the formula;

Therefore the volume of the gas at 20°C is approximately 97.67cm³

Answer: The Atomic Number increases. Hope this helps!!!

Explanation:

Elements are arranged from left to right and top to bottom in order of increasing atomic number. Order generally coincides with increasing atomic mass.

Answer:

The Atomic number increases....

Explanation:

Duh

Half of the estuarine area has waters falling below a certain DO concentration level, and the other half has levels above that level. The level of DO concentration is 2.0 mg/L.

This is because the minimum level of dissolved oxygen in estuaries is 2.0 mg/L, below which the fish and other aquatic life will suffer from hypoxia or low oxygen levels, which may lead to fish kills and other negative impacts on the estuarine ecosystem. The division of estuarine waters into hypoxic and non-hypoxic zones at 2.0 mg/L has been a useful and widely used tool in estuarine ecology, water quality monitoring, and ecosystem management. This level is also used as a regulatory limit in many countries to protect aquatic life and to ensure the estuarine ecosystem's health and sustainability.

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Answer: \(2168 ^{\circ} \text{C}\)

Explanation:

For this question, we can use the formula \(Q=mc \triangle T\), where \(Q\) is the amount of heat absorbed, \(m\) is the mass of the sample, \(c\) is the specific heat constant, and \(\triangle T\) is the change in temperature (final temperature minus initial temperature as stated in the question).

From the question, we know that \(m=175, Q=1.57 \times 10^{6}\). Furthermore, we know that \(c=4.18\) (this is just a fact).

So, we get that \(1.57 \times 10^{6}=175(4.18)(\triangle T)\), meaning \(\triangle T=2146\).

Thus, \(t_{f}-22.0=2146 \longrightarrow t_{f}=\boxed{2168 ^{\circ} \text{C}}\)

Answer:

because battery have it's own voltage in it's composition

The sources of chemical energy from the available options would be batteries and foods.

Chemical energy is a form of energy derived from the chemical properties of materials.

Most batteries contain chemicals that are able to ionize in solution to produce electric currents in circuits. Chemicals in batteries include sodium chloride, nitric acid, sulfuric acid, etc.

Foods contain chemicals that when hydrolyzed in the body, are able to produce energy to sustain the various processes in the body. The chemicals in foods are mostly carbohydrates.

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The number of the nitrogen molecules that reacted with the excess of the hydrogen to make 2 × 10¹⁰ molecules of the ammonia is 1 × 10¹⁰ molecules.

The reaction is given as :

N₂  +  3H₂   --->  2NH₃

The number of the molecules of the ammonia =  2 × 10¹⁰ molecules

1 molecules of the ammonia will produces the 2 molecules of the ammonia

The number of the molecules of the nitrogen = ( 1/ 2) ×2 × 10¹⁰ molecules

The number of the molecules of the nitrogen = 1 × 10¹⁰ molecules.

Thus, the molecules of the nitrogen is 1 × 10¹⁰ molecules.

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After selecting the hypothesis, the next step is to design an experiment to test the hypothesis.

For example, our hypothesis is "deforestation causes soil erosion".

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Answer:

\(\boxed{\small \sf \: Mass \: of \: H_2O =322.2 \: grams}\)

Explanation:

Given:

Mass of ferous (Fe) produced = 750 gram.

To find:

Mass of water produced= ?

Solution:

Molar mass of Fe is 55.84 gram/mol

Let's find out the number of moles of ferous produced.

\( \small \sf Number \: of \: moles = \frac{Given \: mass \: of \: substance }{Molar \: mass \: of \: substance} \)

Substituting the given data in above formula.

\( \small \sf Number \: of \: moles = \frac{750}{55.84} \)

\( \boxed{\small \sf Number \: of \: moles \: of \: Fe= 13.43 \: moles}\)

Now the given reaction is,

\(Fe_3O_4 + 4H_2 \rightarrow 3Fe + 4H_2O\)

now calculate the number of moles of H2O

\( \sf \: \frac{3}{4} = \frac{13.43}{x} \\ \sf x = \frac{13.43 \times 4}{3} \\ \sf x = 17.90 \: moles\)

\( \small \boxed{\sf number \: of \: moles \: of \: H_2O= 17.90 \: moles}\)

mass of one mole of H2O is 18 gram, so we can calculate mass of 17.90 moles.

\(\small \sf \: Mass \: of \: H_2O = 17.90 \times 18 \\ \boxed{\small \sf \: Mass \: of \: H_2O =322.2 \: grams}\)

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The total sample size of sodium sulfate in the given sample is 9.45 g.

The given compound is sodium sulfate and the mass of oxygen present in it is 3.15 g. We have to determine the total sample size (in grams) for this sample of sodium sulfate. Let the total sample size of sodium sulfate be 'x' g.

We have to determine the value of 'x'.

Mass percent of oxygen in sodium sulfate= Mass of oxygen / Mass of sodium sulfate× 100%Or, 32 / (32+32+16×4)× 100%= 32 / (32+64)× 100%

= 32 / 96× 100%= 33.33%

Now, we have the mass percent of oxygen in the compound, sodium sulfate.

Let the mass of sodium sulfate be x g. Therefore, the mass of oxygen in it will be= 33.33% of x= 0.3333 x g

We have been given the mass of oxygen in sodium sulfate as 3.15 g.Therefore,0.3333 x g = 3.15 g

Or, x = 3.15 / 0.3333 g

= 9.45 g

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Answer:

hi Da kiran wher r u da come fast Da

Answer:

Hydrogen peroxide is a chemical compound with the formula H2O2. In its pure form, it is a very pale blue[5] liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution (3%–6% by weight) in water for consumer use, and in higher concentrations for industrial use.