At the end of which era did the dinosaurs became extinct?

Cenozoic

Jurassic

Mesozoic

Paleozoic

The energy required to separate the two ions to an infinite distance apart is -1.64 * 10⁻¹⁸ J.

The potential energy required to separate two ions to an infinite distance apart is called lattice energy. The equation for lattice energy is given as follows:

U = -N (A * Z⁺ * Z⁻ / r)

where,U represents lattice energy

N represents Avogadro's constant

A represents the Madelung constant

Z+ represents cation's charge

Z- represents anion's charger represents the distance between the ion centers

As given in the question, the distance between the potassium and chloride ions in potassium chloride is 2.8e⁻¹⁰m.

Thus, putting all the values in the formula of lattice energy, we get;

U = -6.022 * 10²³* (2.31 * 10⁻¹⁰ * 1 * 1 / 2.8 * 10⁻¹⁰)U = -1.64 * 10⁻¹⁸J

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The chlorine element is present in group 7.

The elements which has 7 valence electrons , is kept in group 7.

1) Chlorine (Cl):

The atomic number of chlorine is 17 and its electronic configuration is 2,8,7. It has 7 valence electrons. Hence, it will be kept in group 7.

2) Oxygen (O):

The atomic number of oxygen is 8 and its electronic configuration is 2,6.

It has 6 valence electrons. Hence, it will be kept in group 6.

3) Lithium (Li)

The atomic number of chlorine is 3 and its electronic configuration is 2,1. It has 1 valence electrons. Hence, it will be kept in group 1.

4) Calcium (Ca):

The atomic number of calcium is 20 and its electronic configuration is 2,8,8,2. It has 2 valence electrons. Hence, it will be kept in group 2.

Therefore, chlorine element will be kept in group 7.

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Answer:

Below

Explanation:

The AMOUNT of matter the book contains is 2.5 kg.

   this mass is the same no matter where the book is located....on earth, the moon, in space....still 2.5 kg

Answer:

Baseball

Explanation:

The baseball has molecules that are more tightly packed than any other ball on this list here; you could also argue that it is a tennis ball, but the size of a baseball is probably smaller than a tennis ball's

Answer: Baseball

Explanation: has the most mass

Answer:

A biologist discovered what she thinks is a new life form. Which characteristic must the biologist observe and compare to other known organisms in order to conclude that her discovery is a new organism?

Growth

Minerals: The composition of a mineral can be expressed as a CHEMICAL FORMULA, which simply gives the proportions of the different elements and groups of elements in the mineral. The latter notion (groups of elements) comes into play for those minerals which have a restricted range of composition.

Rocks: Most rocks contain silicate minerals, compounds that include silica tetrahedra in their crystal lattice, and account for about one-third of all known mineral species and about 95% of the earth's crust. The proportion of silica in rocks and minerals is a major factor in determining their names and properties.

Lime: is a calcium-containing inorganic material composed primarily of oxides and hydroxide, usually calcium oxide and/or calcium hydroxide. It is also the name for calcium oxide which occurs as a product of coal-seam fires and in altered limestone xenoliths in volcanic ejecta.

Ores: Ore is natural rock or sediment that contains one or more valuable minerals, typically containing metals, that can be mined, treated and sold at a profit. Ore is extracted from the earth through mining and treated or refined, often via smelting, to extract the valuable metals or minerals.

Mortars: made from magnesia-phosphate cement were observed to set within 15 minutes at 22°C and to harden within 1 hour. The major hydrate formed was struvite, NH4MgPO4·6H2O, usually accompanied by schertelite, (NH42Mg(HPO4)2·4H2O, at least initially. Some hydration products also contained dittmarite, NH4MgPO4·H2O, and/or stercorite, NaNH4HPO4·4H2O, but these were present only as minor constituents.

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The automobile can drive about 216.49 km on the mixed fuel if you are limited by your supply of 20.0 L of methanol.

The step by step solution is as follows :

Density of the fuel = 0.775 g/mL ; Density of methanol = 0.787 g/mL ; Density of gasoline = 0.703 g/mL.

The mixture contains 85% of methanol and 15% of gasoline by mass.

Mass of fuel in 20 L methanol = Volume of methanol × Density of fuel= 20 L × 0.775 g/mL = 15.5 g/mL

Mass of methanol in fuel = (85/100) × Mass of fuel= (85/100) × 20 L × 0.787 g/mL= 13.37 kg

Mass of gasoline in fuel = (15/100) × Mass of fuel = (15/100) × 20 L × 0.703 g/mL= 2.109 kg

Total mass = Mass of methanol + Mass of gasoline = 13.37 kg + 2.109 kg = 15.479 kg

Density of the fuel = 0.775 g/mL (given)

Volume of the fuel = Mass / Density = 15.479 kg / 0.775 g/mL = 19.97 L

Fuel efficiency = 25.5 miles per gallon

1 mile = 1.60934 kilometers

1 gallon = 3.78541 liters

Conversion factor = 1.60934 km / 3.78541 L ≈ 0.42514 km/L

Thus, the automobile can drive about 216.49 km on the mixed fuel if you are limited by your supply of 20.0 L of methanol.

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Answer:

Explanation:

A biography is a specialized form of history. It is an account of events based upon the example of one person's life. There are four basic types of biographies: historical fiction, academic, fictional academic, and the prophetic biography.

Answer:

78 pairs of chromosomes

Explanation:

The oceans have an almost unlimited buffering capacity for rather harmless phosphorus species and some marine life.

Most of them will benefit from increased phosphorus levels in rivers. The global average phosphate concentration in the oceans will increase by about 20 ppm if flows double. If the flow rate is doubled, the increase in concentration is only about 10 ppm.

If the concentration of phosphorus in rivers suddenly increases, the ocean will start absorbing phosphorus, and the temperature of the oceans will in turn rise, leading to further corrosion and the release of toxins that can kill marine life and even make people sick.

The global average phosphate concentration in the oceans would slowly decrease over time as the ocean slowly absorbs phosphorus and the concentration in rivers slowly decreases.

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Answer:

CaCO3 + 2HCl ---> CaCl2 + H2O + CO2

Explanation:

The reaction between solid calcium carbonate and a mineral acid such as aqueous HCl is a neutralization reaction and occurs with the evolution of CO2 gas.

The balanced equation is given below

CaCO3 + 2HCl ---> CaCl2 + H20 + CO2

The product CaCl2 is water soluble which accounts for why the stain is removed, while CO2 gas escapes away from the reaction surface.

Answer:

CaCO3(s) + 2HCl(aq) -------> CaCl2(aq) + 2CO2(g) + H2O(l)

Explanation:

CaCO3(s) + 2HCl(aq) -------> CaCl2(aq) + 2CO2(g) + H2O(l)

When an acid reacts with a metal carbonate a salt, carbon dioxide and water are formed. Hard water usually contain Ca^2+ in the form of Ca(HCO3)2. Minor heating causes CaCO3(calcium carbonate) to deposit on surfaces through which the hard water passes.

Calcium carbonate reacts with acids to produce a calcium salt, water and carbon dioxide: Calcium carbonate + Hydrochloric acid → Calcium chloride + Water + Carbon dioxide. The carbonate radical breaks up into carbon dioxide and oxygen; the oxygen binds with the acid's hydrogen ions to make water; and a solution of calcium chloride remains.

Answer:

Niels Bohr

Explanation:

1 mole of Al is required.

Stoichiometry is the study of the quantitative relationships between the reactants and products in a chemical reaction. It is based on the principle of the conservation of mass, which states that the total mass of a system remains constant, regardless of any changes that take place within the system. In other words, the total mass of the reactants must equal the total mass of the products.

In stoichiometry, the coefficients in a balanced chemical equation are used to calculate the amount of reactants and products needed for a specific reaction.

We know that;

Number of moles of H2 = 3g/2 g/mol

= 1.5 moles

If 2 moles of Al produces 3 moles of products

x moles of Al produces 1.5 moles product

x = 1 mole

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P-aminophenol has a molar mass of 109.13 g/mol. Acetaminophen has a molar mass of 151.17 g/mol. Acetic anhydride has a capacity of 1.1 mL.

The mass of acetaminophen, stated as 0.157g, must be multiplied by the molar mass of acetaminophen to get the theoretical yield. It weighs 151.2g in this case. The theoretical yield thus becomes 0.217g.

A measurement called production yield is obtained by dividing the number of high-quality parts produced by the total number of parts started in production.

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The mass percent of gold in the piece is 79.08%

The density of a substance is simply defined as the mass of the subtance per unit volume of the substance. Mathematically, it can be expressed as

Density = mass / volume

Thus,

Mass = density × volume

Mass = density × volume

Mass of gold = 19.3 × V

Mass of gold = 19.3V

Mass = density × volume

Mass of silver = 10.5 × (1.25 - V)

Mass of silver = 13.125 - 10.5V

Mass of piece = mass of gold + mass of silver

20.5 = 19.3V + 13.125 - 10.5V

Collect like terms

19.3V - 10.5V = 20.5 - 13.125

8.8V = 7.375

Divide both sides by 8.8

V = 7.375 / 8.8

Volume of gold = 0.84 cm³

Thus,

Mass of gold = 19.3V

Mass of gold = 19.3 × 0.84

Mass of gold = 16.212 g

Mass percent of gold = (mass of gold / mass of piece) × 100

Mass percent of gold = (16.212 / 20.5) × 100

Mass percent of gold = 79.08%

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Hormone precursor analogs can be synthesized through electrophilic aromatic substitution reactions, and their regioselectivity can be analyzed using NMR spectroscopy.

Hormone precursor analogs can be synthesized by performing electrophilic aromatic substitution reactions, which involve replacing a hydrogen atom on an aromatic ring with an electrophilic group. The regioselectivity of the reaction determines the specific position where the substitution occurs. NMR spectroscopy can be used to analyze the regioselectivity by providing information about the chemical shifts and coupling patterns of the protons in the synthesized analog.

In electrophilic aromatic substitution reactions, a precursor molecule containing an aromatic ring is treated with an electrophile under appropriate reaction conditions. The electrophile reacts with the aromatic ring, replacing one of the hydrogen atoms and forming a new bond. The regioselectivity of the reaction depends on factors such as the nature of the electrophile and the substituents present on the aromatic ring. Different positions on the ring can be selectively substituted, leading to the synthesis of various hormone precursor analogs.

NMR spectroscopy is a powerful analytical technique that can be used to study the regioselectivity of the reaction. By analyzing the NMR spectrum of the synthesized analog, valuable information about the position of the substitution can be obtained. The chemical shifts observed in the NMR spectrum provide insights into the electronic environment of the substituted proton, allowing for the determination of the regioselectivity. Coupling patterns between neighboring protons can also reveal the connectivity of the aromatic ring and confirm the desired substitution.

In summary, hormone precursor analogs can be synthesized via electrophilic aromatic substitution reactions, and their regioselectivity can be analyzed using NMR spectroscopy. This combination of synthetic chemistry and analytical techniques enables researchers to design and study novel analogs with specific substitution patterns, contributing to the understanding and development of hormone-related compounds.

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Answer: Wheat flour, edible oil, egg white, lettuce preservative, meat or poultry marinade, vegetable antibacterial wash.

Explanation:

hydrogen peroxide is used as a bleaching agent in some food

I hope this helped

Answer:30 moles of oxygen are required if 12 moles of  are consumed.

Explanation:The given balanced equation is:

From this balanced equation, there is 2:5 mol ratio between  and  .

We are asked to calculate the moles of  required to react with 12 moles of .

It's a mol to mol conversion and the set up for this would be as:

=

So, 30 moles of oxygen are required to react with 12 moles of  .

Potassium oxide (K₂O): ionic compound.

Reaction:

K₂O + H₂O →2KOH

KOH = strong base, pH>7

Answer:

When the average kinetic energy of the molecules goes up (a rise in temperature), the average speed of the molecules increases. And lower average kinetic energy of the molecules means they have lower speed. ... When heat (energy) goes into a substance one of two things can happen

Explanation:

hope this helpss!!!

Answer:

The answer is option A.

Distilled water

Since all the chemicals that will cause hardness in the water has been removed.

Hope this helps.

Atoms of hydrogen are then balanced. Watch the following video to learn more about oxygen atoms. C12H22O11 with 12O2 equals 12CO2 plus 11H2O.

Balance C12H22O11 + O2 CO2 + H2O

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Answer: 0.44

Explanation:

The specific heat of iron if 985 J of energy is required to raise the temperature of 158.5 g from 10.0°C to 24.0°C is 0.44J/g°C.

The specific heat capacity of a substance can be calculated using the following formula:

Q = m × c × ∆T

Where;

985 = 158.5 × c × (24°C - 10°C)

985 = 2219c

c = 985/2219

c = 0.44 J/g°C

Therefore, the specific heat of iron if 985 J of energy is required to raise the temperature of 158.5 g from 10.0°C to 24.0°C is 0.44J/g°C.

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Explanation:

When an object undergoes a physical change (solid to liquid, decrease in temperature etc.), the mass of the object remains constant.

When water freezes, the water molecules vibrate closer to one another and there is less space between the molecules.

The same number of water molecules now occupy a smaller volume, therefore their density increases.

The correct answer is the 3rd option.

At the time when the water should be freezed so here the density should be decreased.

The density refers to the mass of the unit volume with respect to the material substance.

The formula for density should be d = M/v

So here d means the density

And, m means mass

V means the volume

So it should be expressed in units with respect to the units of grams per cubic centimeter.

Hence the last option is correct.

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The molar mass of potassium nitrate is 101.102 g/mol while that of potassium nitrite is 85.103 g/mol.

Potassium nitrate goes by the chemical formula \(KNO_3\).

K = 39.098

N = 14.007

O = 15.999

Molar mass of  \(KNO_3\) = 39.098 + 14.007 + (3x15.999)

                                    = 101.102 g/mol

Potassium nitrite goes by the chemical formula, \(KNO_2\).

Molar mass of \(KNO_2\) = 39.098 + 14.007 + (2x15.999)

                                   = 85.103 g/mol

In other words, the molar masses of KNO3 and KNO2 are 101.102 g/mol and 85.103 g/mol respectively.

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Transition metals are much stronger and denser than alkali metals and alkaline earth metals and it is located between group 2 and group 3 of the periodic table.

Alkali metals and alkaline earth metals form ions with a +1 charge while the transition metals can form ions with variable charges. The transition metals are much harder, stronger and denser. They have much higher melting points . The transition metals are much less reactive. The alkali metals react with water, oxygen and halogens while the transition metals either react very slowly or do not react at all. A group 1 of the periodic table that is alkali metal will tarnish in the presence of oxygen as a metal oxide is formed. When cut with a knife the shiny appearance of the metal disappears in seconds as it is covered by the dull metal oxide.

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Answer:

6.25 grams of CaCO3 in the egg shell.

Explanation:

The molar mass of calcium carbonate (CaCO3) is 100.09 g/mol. To find the number of grams of CaCO3 in the egg shell, you can multiply the number of moles (0.0626) by the molar mass (100.09):

0.0626 moles * 100.09 g/mol = 6.25 grams

So, there are 6.25 grams of CaCO3 in the egg shell.