16. Who was the first modern chemist

Some examples of chemical compounds that are formed by swapping the valencies are:

In chemistry, one can analyze an element's combining capacity with other atoms through its valency, crucial for creating chemical compounds or molecules.

Recently, an article featured a comparable description detailing atomic valence as "the electrons utilized by the atom during bonding." There are also two distinct formulas available to determine the element's level of valence.

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24. To calculate the molarity of a solution, we must first find out how many moles of [tex]BaI_2[/tex] are in the solution.

Molar mass of BaI2 = (1 x atomic mass of Ba) + (2 x atomic mass of I)

= (1 x 137.33 g/mol) + (2 x 126.90 g/mol)

= 137.33 g/mol + 253.80 g/mol

= 391.13 g/mol

Number of moles of BaI2 = mass of BaI2 / molar mass of BaI2

= 413 g / 391.13 g/mol

= 1.056 mol

the molarity of the solution using the formula:

Molarity (M) = moles of solute / volume of solution (in liters)

Volume of solution = 750 ml = 750 ml / 1000 ml/L = 0.750 L

Molarity = 1.056 mol / 0.750 L

= 1.408 M

Therefore, the molarity of the solution is 1.408 M.

25. a. [tex]P_20_7[/tex] - Ionic compound (Phosphorus(V) oxide)

b. [tex]SnBr_2[/tex] - Ionic compound (Tin(II) bromide)

c. [tex]Fe(OH)_2[/tex]-  Ionic compound (Iron(II) hydroxide)

d. [tex]Cl_30_8[/tex] - Not a valid chemical formula

26.

A. (NH4)2CO3 is soluble in water (NH4) in an ionic substance called 2CO3 containing the ions carbonate and ammonium.

B. Fe(OH)2 is insoluble in water. Iron(II) hydroxide is only sparingly soluble.

C. CaOH is not soluble in water. Only very little calcium hydroxide is soluble.

D. PbCl2 is insoluble in water. The chloride of lead(II) is sparingly soluble.

27. FeS + 2KCl = FeCl2 + K2S

FeS is an insoluble precipitate.

2KCl dissolves in aqueous solution.

ZnCl2 + SrSO4 = ZnSO4 + SrCl2

SrSO4 is an insoluble precipitate.

ZnCl2 dissolves in aqueous solution.

28. In salt water, the solute is the salt (sodium chloride, or NaCl), and the solvent is water. The element which dissolves in the solvent to form a solution is called solute.

29. Charles's law states that, if the pressure and volume of a gas remain constant, the volume of a gas falls as the temperature increases. As a result, the capacity of the balloon will decrease as it ascends to altitudes where the temperature is -15 °C.

30. The average kinetic energy of the particles of a substance increases with increase in its temperature. This is because temperature is a gauge for the specific kinetic energy of the constituent particles of a substance. On the other hand, the average kinetic energy falls as the temperature increases.

31. When the volume of a gas decreases, its pressure increases. Boyle's law, which states that at a given temperature, the pressure of a gas is inversely proportional to its volume, describes this relationship. On the other hand, pressure falls when volume increases.

32. The pressure of a gas increases along with its temperature. Gay–Lussac's law, which states that the pressure of a gas is directly proportional to its temperature, given the volume and volume of the gas is constant, describes this relationship.

33. The volume of a syringe is reduced as a marshmallow is pressed and the plunger is depressed. As a result the pressure inside the syringe increases. This is because Boyle's law states that the volume and pressure of a gas are inversely proportional. The decrease in volume causes the air inside the syringe to contract, exerting more pressure on the marshmallow, which is then crushed.

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From the uncompleted equation, we have:

LiOH + HBr ->

Since we have two ionic substance reacting, we can conclude that the type of reaction is double displacement reaction as the reaction will involve exchange of ions between the reacting species.

The products of the reaction can be obtained by balancing the equation. This is shown below:

LiOH + HBr ->

By exchange of ion, we have

LiOH + HBr -> LiBr + H₂O

Now, observing the equation, we can see that the equation is balanced.

Thus, the products of the reaction are LiBr and H₂O

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Answer:

Basically, they r different chemically and radically.

Explanation:

Here is how:

So,

Magnesium compounds found in surface water can vary depending on the specific water source and environmental factors. However, some common magnesium compounds that can be present in surface water include:

Magnesium Carbonate (MgCO3): This compound can form when magnesium ions (Mg2+) react with carbonate ions (CO32-) present in the water. It is often found in areas where there are limestone or dolomite formations.

Magnesium Hydroxide (Mg(OH)2): This compound can occur when magnesium ions react with hydroxide ions (OH-) in the water. It is more likely to be present in alkaline or basic water conditions.

Magnesium Sulfate (MgSO4): This compound can form when magnesium ions react with sulfate ions (SO42-) in the water. It can be found in areas where there are sulfates present, such as in some mining or industrial areas.

Now, let's compare these magnesium compounds to minerals like calcium carbonate and soluble sugar in lemonade:

Calcium Carbonate (CaCO3): Calcium carbonate is a common mineral found in many natural sources, including limestone, chalk, and shells of marine organisms. It is insoluble in water and tends to precipitate out of the solution, forming solid deposits or scale.

Soluble Sugar in Lemonade: Lemonade typically contains sucrose or other soluble sugars. These sugars are highly soluble in water, meaning they readily dissolve and form a homogeneous mixture with water.

In comparison to magnesium compounds found in surface water, calcium carbonate and soluble sugar in lemonade are chemically different. Calcium carbonate is insoluble in water and tends to separate from the solution, while soluble sugars dissolve completely.

Answer:

First, let's consider the ratio: 1:25. This means that for every 1 gram of solute, we have 25 milliliters of solvent. Therefore, if we have 100 milliliters of the solution, we can set up a proportion to find the amount of solute in grams:

1 gram solute / 25 milliliters solvent = x grams solute / 100 milliliters solution

Cross-multiplying, we get:

25 * x = 1 * 100

25x = 100

x = 100 / 25

x = 4

So, in 100 milliliters of a 1:25 (weight/volume) solution, there are 4 grams of solute.

To calculate the percent strength, we divide the mass of the solute (4 grams) by the volume of the solution (100 milliliters) and multiply by 100:

Percent strength = (mass of solute / volume of solution) * 100

Percent strength = (4 g / 100 mL) * 100

Percent strength = 4%

Therefore, the percent strength of a 1:25 (weight/volume) solution is 4%.

To determine the molal concentration of a solution, we need to know the amount of solute (ethanol) in moles and the mass of the solvent (usually water) in kilograms.

Given that the solution is 30% ethanol, it means that there are 30 grams of ethanol in 100 grams of the solution. Let's assume we have 100 grams of the solution.

To find the amount of ethanol in moles, we need to convert grams to moles using the molar mass of ethanol (C2H5OH).

The molar mass of C2H5OH:

2 * atomic mass of carbon (C) = 2 * 12.01 g/mol = 24.02 g/mol

6 * atomic mass of hydrogen (H) = 6 * 1.01 g/mol = 6.06 g/mol

1 * atomic mass of oxygen (O) = 1 * 16.00 g/mol = 16.00 g/mol

1 * atomic mass of hydrogen (H) = 1 * 1.01 g/mol = 1.01 g/mol

Total molar mass of C2H5OH = 24.02 + 6.06 + 16.00 + 1.01 = 47.09 g/mol

Now, let's calculate the amount of ethanol in moles:

30 grams ethanol * (1 mol / 47.09 g) = 0.637 moles ethanol

Next, we need to determine the mass of the solvent (water) in kilograms. Let's assume we have 100 grams of the solution, so the mass of water would be 100 - 30 = 70 grams.

Converting the mass of water to kilograms:

70 grams * (1 kg / 1000 grams) = 0.07 kg

Finally, we can calculate the molal concentration (m) using the formula:

molal concentration (m) = moles of solute/mass of solvent in kilograms

m = 0.637 moles / 0.07 kg ≈ 9.10 mol/kg

Therefore, the molal concentration of the 30% ethanol solution (C2H5OH) is approximately 9.10 mol/kg.

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There are approximately 2.8939 x[tex]10^2^4[/tex] carbon atoms in 0.37 mol of procaine.  The molecular formula of procaine (C₁₃H₂₀N₂₀₂), one can see that there are 13 carbon atoms (C13) in one molecule of procaine.

Avogadro's number (6.022 x [tex]10^2^3[/tex]) represents the number of particles (atoms, molecules, or formula units) in one mole of a substance

The number of molecules of procaine in 0.37 mol:

Number of molecules = 0.37 mol x (6.022 x[tex]10^2^3[/tex] molecules/mol)

Number of carbon atoms = Number of molecules x 13 carbon atoms/molecule

Number of molecules = 0.37 mol x (6.022 x [tex]10^2^3[/tex]molecules/mol)

= 2.22614 x [tex]10^2^3[/tex]molecules

Number of carbon atoms = 2.22614 x [tex]10^2^3[/tex] molecules x 13 carbon atoms/molecule

= 2.8939 x [tex]10^2^4[/tex]carbon atoms

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Answer:

Particulate matter pollution decreases the amount of sunlight plants can absorb for photosynthesis.

Explanation:

The following chemical equations must be balanced:

1. N2 + 3 H2 → 2 NH3

Type: Synthesis reaction

2. 2 KClO3 → 2 KCl + 3 O2

Type: Single Replacement reaction

3. 2 NaF + ZnCl2 → ZnF2 + 2 NaCl

Type- Decomposition reaction

4. 2 AlBr3 + 3 Ca(OH)2 → Al2(OH)6 + 6 CaBr2

Type- Double Replacement reaction

5. 2 H2 + O2 → 2 H2O

Type: Combustion reaction

6. 2 AgNO3 + MgCl2 → 2 AgCl + Mg(NO3)2

Type: Synthesis reaction

7. 2 Al + 6 HCl → 2 AlCl3 + 3 H2

Type: Decomposition reaction

8. C3H8 + 5 O2 → 3 CO2 + 4 H2O

Type: Combustion reaction

9. 2 FeCl3 + 6 NaOH → Fe2O3 + 6 NaCl + 3 H2O

Type: Double Replacement reaction

10. 4 P + 5 O2 → 2 P2O5

Type: Synthesis reaction

11. 2 Na + 2 H2O → 2 NaOH + H2

Type: Single Replacement reaction

12. 2 Ag2O → 4 Ag + O2

Type: Decomposition reaction

13. C6H12O6 + 6 O2 → 6 CO2 + 6 H2O

Type: Combustion reaction

14. 2 KBr + MgCl2 → 2 KCl + MgBr2

Type: Double Replacement reaction

15. 2 HNO3 + Ba(OH)2 → Ba(NO3)2 + 2 H2O

Type: Double Replacement reaction

16. C5H12 + 8 O2 → 5 CO2 + 6 H2O

Type: Combustion reaction

17. 4 Al + 3 O2 → 2 Al2O3

Type: Synthesis reaction

18. Fe2O3 + 2 Al → 2 Fe + Al2O3

Type: Single Replacement reaction

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Answer:

Sodium (Na) is a highly reactive metal, while sodium chloride (NaCl) is a compound formed by the combination of sodium and chlorine (Cl). Sodium exists as a pure element, whereas sodium chloride is a stable, crystalline compound.

Sodium is a soft, silvery-white metal that is highly reactive and can easily react with water or air. In contrast, sodium chloride is a white crystalline solid that is highly stable and does not react readily with water or air. Sodium chloride is commonly known as table salt and is widely used as a seasoning and food preservative.

Answer:

the water arrives on the earth in the form of water rich objects(planetesimals)

Answer:

The limiting reactant is BF3 because there is less of it than Li2SO4.

Explanation:

Theoretically, if 20 grams of hydrogen reacts then 112.5 grams of ammonia is produced.

The balanced chemical equation can be given as:

N₂+3H₂→ 2NH₃

From stoichiometry, 2 mol of NH₃is produced from 3 mol of H₂

5 mol of NH₃ will be produced from = 3/2×5 = 7.5 mol of H₂

∴mass of H₂=7.5×2= 15gm of H₂.

Excess reagents are those reactants in a chemical reaction that are not exhausted at the end of the reaction. A completely exhausted or reacted reagent is called a limiting reagent because its amount limits the number of products formed. In this reaction, the excess reagent is Nitrogen as 35 grams of nitrogen and 15 grams of hydrogen react to produce 34 grams of ammonia.

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To calculate the molarity of a solution, we need to determine the number of moles of the solute (Bal2) and then divide it by the volume of the solution in liters.

Given:

Mass of Bal2 = 413 g

Volume of solution = 750 ml = 0.75 L

1. Calculate the number of moles of Bal2:

First, we need to convert the mass of Bal2 to moles using its molar mass. The molar mass of Bal2 can be calculated by summing the atomic masses of boron (B) and iodine (I):

Molar mass of Bal2 = (atomic mass of B × 1) + (atomic mass of I × 2)

Molar mass of Bal2 = (10.81 g/mol × 1) + (126.90 g/mol × 2)

Molar mass of Bal2 = 10.81 g/mol + 253.80 g/mol

Molar mass of Bal2 = 264.61 g/mol

Now we can calculate the number of moles of Bal2:

Moles of Bal2 = Mass of Bal2 / Molar mass of Bal2

Moles of Bal2 = 413 g / 264.61 g/mol

Moles of Bal2 ≈ 1.561 mol

2. Calculate the molarity of the solution:

Molarity (M) = Moles of solute / Volume of solution (in liters)

Molarity (M) = 1.561 mol / 0.75 L

Molarity (M) ≈ 2.081 M

Therefore, the molarity of the solution is approximately 2.081 M.

The molarity of the solution is approximately 1.408 M as to calculate the molarity of a solution, one must need to know the number of moles of the solute and the volume of the solution in liters.

The molar mass of BaI₂ is:

Ba (barium) atomic mass = 137.33 g/mol

I (iodine) atomic mass = 126.90 g/mol

Molar mass of  BaI₂ = (Ba atomic mass) + 2 × (I atomic mass)

= 137.33 + 2 × 126.90

= 137.33 + 253.80

= 391.13 g/mol

Given that the mass of BaI₂ is 413 g,

Number of moles = Mass / Molar mass

= 413 g / 391.13 g/mol

= 1.056 moles

Volume of solution = 750 ml = 750/1000 = 0.75 L

Finally, one can calculate the molarity of the solution using the formula:

Molarity = Number of moles / Volume of solution

= 1.056 moles / 0.75 L

= 1.408 M

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Answer:

[tex]\huge\boxed{\sf 1.869\ L}[/tex]

Explanation:

Given that,

Mass = m = 2.67 g

Molar mass (O₂) = 16 × 2 = 32 g/mol

We know that,

No. of moles = 2.67 / 32

No. of moles = 0.08 moles

Also, we know that:

1 × 0.08 moles of O₂ at STP = 22.4 × 0.08 L

So, the volume of 0.08 moles of oxygen gas at STP will be 1.869 L.

[tex]\rule[225]{225}{2}[/tex]

The conjugate acid-base pairs in the reaction between ammonia and hydrofluoric acid in aqueous solution are NH3/NH4+ and HF/F-.

In the reaction between ammonia (NH3) and hydrofluoric acid (HF) in aqueous solution, the following conjugate acid-base pairs can be identified:

NH3 (ammonia) and NH4+ (ammonium ion):

Ammonia (NH3) acts as a base by accepting a proton (H+) from hydrofluoric acid (HF) to form the ammonium ion (NH4+). In this reaction, ammonia acts as a Lewis base by donating an electron pair to the proton, resulting in the formation of the ammonium ion as the conjugate acid.

HF (hydrofluoric acid) and F- (fluoride ion):

Hydrofluoric acid (HF) acts as an acid by donating a proton (H+) to ammonia (NH3) to form the fluoride ion (F-).

In this reaction, hydrofluoric acid acts as a Lewis acid by accepting an electron pair from ammonia, resulting in the formation of the fluoride ion as the conjugate base.

To summarize, in the reaction NH3 (aq) + HF (aq) = NH4+ (aq) + F- (aq), the conjugate acid-base pairs are NH3/NH4+ and HF/F-. Ammonia (NH3) is the base that forms its conjugate acid, the ammonium ion (NH4+), while hydrofluoric acid (HF) is the acid that forms its conjugate base, the fluoride ion (F-).

It is important to note that in an aqueous solution, ammonia is present as NH3 molecules, and hydrofluoric acid dissociates into H+ and F- ions. The resulting ammonium ion (NH4+) and fluoride ion (F-) remain in the solution.

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The name for H2SO4(aq) is Sulfuric acid.

Sulfuric acid (H2SO4) is a highly corrosive and strong acid. It is one of the most important industrial chemicals produced worldwide. Sulfuric acid is commonly used in various industries for a wide range of applications. It is used in the production of fertilizers, detergents, dyes, pharmaceuticals, and various chemical processes.

Sulfuric acid is also utilized in laboratories for its acidic properties and as a dehydrating agent due to its strong affinity for water. It is a dense, oily liquid that is colorless when pure but can appear yellowish or brownish due to impurities. When handling sulfuric acid, caution must be exercised as it can cause severe burns and is harmful if ingested or inhaled.

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The underlying foundation of all these emissions can be traced back to the burning of fossil fuels, making it the dominant and pervasive cause of human-induced greenhouse gas emissions.

The human activity that is intricately connected to every piece of the pie chart representing greenhouse gas emissions is the burning of fossil fuels. Fossil fuel combustion, including coal, oil, and natural gas, is the primary contributor to the rise in greenhouse gas concentrations over the past 150 years. When these fuels are burned for energy generation, transportation, industrial processes, and residential use, carbon dioxide (CO2) is released into the atmosphere. CO2 is the most significant greenhouse gas, accounting for approximately 75% of total emissions. The other greenhouse gases, such as methane (CH4) and nitrous oxide (N2O), are also released as byproducts of certain human activities, such as agriculture, deforestation, and waste management.

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Answer:

Question 1:

1: a metal and a nonmetal

3: a metal and a polyatomic anion

4: a polyatomic cation and a metal

Question 2:

Cations give away electrons and anions accept those electrons

The volume the gas will occupy at pressure of 138.7 KPa, given that the temperature remains the same is 136 mL

The new volume of the gas, given that the new pressure is 138.7 KPa can be obtained as follow:

P₁V₁ = P₂V₂

Inputting the given parameters, we have:

135.5 × 139.3 = 138.7 × V₂

18875.17 = 138.7 × V₂

Divide both side by 138.7

V₂ = 18875.17 / 138.7

V₂ = 136 mL

Thus, we can conclude that the volume of the gas will be 136 mL

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An impact of the specific heat of the water on the planet is that islands and coastal places have moderately pleasant climates. Therefore, option A is correct.

The specific heat of water is relatively high compared to other substances. This means that water requires a significant amount of heat energy to increase its temperature. As a result, water has a stabilizing effect on the climate of coastal and island regions.

The high specific heat of the water helps to moderate temperature changes, resulting in milder and more pleasant climates in these areas.

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The boiling point of a solution is influenced by the presence of solute particles, which can cause a change in the boiling point compared to the pure solvent. This phenomenon is known as boiling point elevation.

The magnitude of boiling point elevation depends on the concentration of the solute and the nature of the solute particles. In general, the greater the concentration of solute particles, the greater the boiling point elevation.

Comparing a 0.5m sodium chloride (NaCl) solution to a 0.3m aluminum sulfate ([tex]Al_2(SO_4)_3[/tex]) solution, we can determine the relative boiling point elevation.

Sodium chloride (NaCl) dissociates into two ions in solution (Na+ and Cl-), while aluminum sulfate ([tex]Al_2(SO_4)_3[/tex])dissociates into three ions (2[tex]Al_3[/tex]+ and 3[tex]SO_4[/tex]2-). This means that the aluminum sulfate solution will have a greater concentration of solute particles per mole than the sodium chloride solution.

Therefore, the boiling point of the 0.5m sodium chloride solution will be lower than the boiling point of the 0.3m aluminum sulfate solution.

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7.54 *[tex]10^8[/tex] meters is  75.4 nanometers.

To convert 7.54 *  [tex]10^8[/tex] meters to nanometers, you can multiply the value by [tex]10^9[/tex]

as,  [tex]10^9[/tex]nanometers = 1  meter.

7.54 * [tex]10^8[/tex] m * [tex]10^9[/tex] =  7.54 x [tex]10^1[/tex] nm

Therefore, 7.54 *[tex]10^8[/tex] meters is equal to 75.4 nanometers.

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To convert 7.54 x 10^-8 meters to nanometers, you multiply 7.54 x 10^-8 by 1 x 10^9 to get 75.4 nanometers.

To convert meters to nanometers, you need to know that 1 meter is equivalent to 1 x 109 nanometers. Therefore, if you were to convert 7.54 x 10-8 m to nanometers, you would multiply 7.54 x 10-8 by 1 x 109.

Here's how you'd do it: 7.54 x 10-8 m * 1 x 109 nm/m = 75.4 nm. So, 7.54 x 10-8 meters is equivalent to 75.4 nanometers.

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The following chemical equations must be balanced:

1. N2 + 3 H2 → 2 NH3

Type: Synthesis

2. 2 KClO3 → 2 KCl + 3 O2

Type: Single Replacement

3. 2 NaF + ZnCl2 → ZnF2 + 2 NaCl

Type- Decomposition

4. 2 AlBr3 + 3 Ca(OH)2 → Al2(OH)6 + 6 CaBr2

Type- Double Replacement

5. 2 H2 + O2 → 2 H2O

Type: Combustion

6. 2 AgNO3 + MgCl2 → 2 AgCl + Mg(NO3)2

Type: Synthesis

7. 2 Al + 6 HCl → 2 AlCl3 + 3 H2

Type: Decomposition

8. C3H8 + 5 O2 → 3 CO2 + 4 H2O

Type: Combustion

9. 2 FeCl3 + 6 NaOH → Fe2O3 + 6 NaCl + 3 H2O

Type: Double Replacement

10. 4 P + 5 O2 → 2 P2O5

Type: Synthesis

11. 2 Na + 2 H2O → 2 NaOH + H2

Type: Single Replacement

12. 2 Ag2O → 4 Ag + O2

Type: Decomposition

13. C6H12O6 + 6 O2 → 6 CO2 + 6 H2O

Type: Combustion

14. 2 KBr + MgCl2 → 2 KCl + MgBr2

Type: Double Replacement

15. 2 HNO3 + Ba(OH)2 → Ba(NO3)2 + 2 H2O

Type: Double Replacement

16. C5H12 + 8 O2 → 5 CO2 + 6 H2O

Type: Combustion

17. 4 Al + 3 O2 → 2 Al2O3

Type: Synthesis

18. Fe2O3 + 2 Al → 2 Fe + Al2O3

Type: Single Replacement

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Answer:

a. P2O7 - This is a covalent compound. P and O have similar electronegativities and they form a covalent bond between them, rather than an ionic bond.

b. SnBr2 - This is a covalent compound. Sn and Br have different electronegativities, but they still form a covalent bond due to their relatively small difference in electronegativity.

c. Fe(OH)2 - This is an ionic compound. Fe has a higher electronegativity than O and H, so it tends to donate its electrons and become positively charged. This results in the formation of ionic bonds between Fe and OH.

d. Cl3O8 - This is a covalent compound. Cl and O have similar electronegativities, so they form covalent bonds rather than ionic bonds.