Giraffes with short necks lived in arid regions. Over time, grasses disappeared, forcing giraffes to eat from trees. Mutations in the genome led to some giraffes inheriting the trait for long necks. Over time, there were more giraffes with long necks in the region. What are the two reasons for the change in the population of giraffes? (More than one answer)

- adaptation?
- artificial selection?
- natural selection?
- harmful genetic traits?

An ion of magnesium has 12 protons and a charge of +2. The number of electrons in these ions are 12.

Electrons are negatively charged ions that are present around the nucleus of the atom. There are many electrons in one atom of the element. They revolve around the negatively charged nucleus.

Here, an ion of magnesium is given, that has 12 protons and a charge of 2+.  To count the number of electrons, we can count the number of protons. The protons are equal to the number of electrons. Magnesium is an alkaline earth metal whose atomic number is 12.

Protons = electrons(12 electrons).

However, it has a charge of +2 which means it loses two electrons, thus, there are 10 electrons.

Thus, the number of electrons in these ions is 12.

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Nutmeg was called the 'spice of madness' because of the historical frenzy and extreme control over its trade by European colonists. The Dutch, in particular, went to great lengths to maintain their monopoly, going as far as employing the death penalty for unauthorized trade. Moreover, the term 'madness' could also metaphorically refer to historical instances of intoxication from nutmeg in large doses.

Nutmeg has been called the 'spice of madness' due to the history of its trade, which involved extreme measures by European colonists to control its supply and ensure monopoly profits. The search for a sea route to the Spice Islands, driven by the loss of Constantinople and the fall of the Byzantine Empire in 1453, was motivated by the high demand for spices like nutmeg. European powers, particularly the Dutch, took control of the nutmeg-producing islands and established a monopoly, punishing anyone who dared grow or sell the spice without permission with the death penalty. This ferocious control and the lengths that Europeans went to for these spices, including the destruction of nutmeg trees on outlying islands, reflect the 'madness' associated with the lucrative spice.

In addition to its economic implications, nutmeg has been involved in various historical anecdotes of madness and hallucinatory episodes, sometimes similarly to how ergot poisoning was suspected in other historical outbreaks of convulsions and hallucinations. However, it is crucial to distinguish between the metaphorical 'madness' driven by the obsessive and often ruthless European pursuit of the spice trade and any actual psychoactive effects of nutmeg, which, in very large doses, can indeed cause symptoms such as delirium or hallucinations.

Answer:

I am pretty sure temperature is wrong. It is actually work.

Explanation:

Scientists use the term joule(s) for heat. Temperature is measured in celcius, kelvin, fahrenheit. Work also uses the same term for measuring; joules. I am pretty sure the right answer is actually work, even though temperature sounds more correct. I learned this in science so I think I am right.

The given values in the problem are:

 .725 M is moles per liter 

300 mL = .300 L 

The solution is:

56.1 g/mol in 300 ml = 56.1g/mol in .3L 

M = (x gram/56.1) /.3L 

.725 = (x gram/56.1)/.3L 

Multiply both sides by .3

.2175 = x grams/56.1 

x = 12.20 g

To make a 0.725mol solution with a volume of 300ml, you need approximately 12.2g of KOH, calculated using the definitions of molality and molar mass.

To answer this question, we will use the definition of molality. Molality (m) is defined as the number of moles of solute per kilogram of solvent. It is given that the molality is 0.725m and the volume is 300.0 ml. Firstly, convert volume to mass. Since the density of water is approximately 1 g/ml, 300.0 ml is approximately 300.0 grams or 0.300 kg. Multiply this by the given molality, 0.725 mol/Kg, to obtain the number of moles of KOH, which is 0.2175 moles.

Now, we need to find the mass of KOH. The molar mass of KOH (K=39.1, O=16, H=1) is approximately 56.1g/mol. Multiply this by the number of moles (0.2175) and you obtain the mass of KOH required, approximately 12.2g.

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Answer: Option (a) is the correct answer.

Explanation:

In a liquid state, particles are held less tightly as compared to a solid state. So, they have some kinetic energy due to which they collide with each other.

As a result, particles of a liquid are able to slide past each other. Hence, they are able to acquire the shape and volume of a container in which they are poured.

Whereas when particles of a liquid can break free from one another and spread out then it means a substance is present in a gaseous state.

When the particles of a liquid can vibrate within their fixed locations then it means the substance is present in a solid state. And, they have definite shape and volume.

Thus, we can conclude that a liquid take the shape of the bottom of its container as the particles of a liquid can flow around one another to new locations.

Final answer:

A calcium ion (Ca²+) and a chloride ion (Cl-) attract each other due to their opposite charges, forming an ionic bond in the compound calcium chloride (CaCl²).

Explanation:

A calcium ion (Ca²+) and a chloride ion (Cl−) will attract each other due to the opposite charges they carry. Calcium donates two electrons to achieve a stable electron configuration, becoming a Ca²+ ion. Each electron is then accepted by a chlorine atom, which becomes a Cl− ion. This transfer leads to the formation of the ionic compound calcium chloride (CaCl²), where the attraction between the positively charged calcium ions and the negatively charged chloride ions results in a strong electrostatic force that holds the compound together in a lattice structure. The ionic bonding between Ca²+ and Cl− is a result of the coulombic attraction described by Coulomb's law, which states that opposite charges attract each other.

In case of the first ionization energy, the first electron is removed from a neutral atom; while in the second ionization energy the electron is removed from a positively charged ion which is found to be an electron deficient species.

Also when the second electron was removed the effective nuclear charge increases as compared to the first electron removal.

As a result there is a strong attraction between the nucleus and the outermost electron of the element. Therefore, the second ionization energy is observed to be higher than the first ionization energy of an element.

The molar mass of the unknown monoprotic acid is calculated to be 109.63 g/mol by first determining the moles of NaOH used and then using the 1:1 mole ratio between the acid and base to find the moles and finally the molar mass of the acid.

In order to determine the molar mass of an unknown monoprotic acid using titration data, we need to first calculate the number of moles of base (NaOH) used in the titration. Given that 20.01 mL (or 0.02001 L) of a 0.098 M NaOH solution were used, we calculate the moles of NaOH:

moles of NaOH = volume (L)  imes molarity (M) = 0.02001 L  imes 0.098 M = 0.00196098 mol NaOH

Since the acid is monoprotic, it will donate one proton to the base, meaning the mole ratio of acid to base is 1:1. Thus, the moles of the unknown acid are also 0.00196098 mol.

To find the molar mass of the acid, we divide the mass of the acid by the moles:

Molar Mass = mass (g) / moles = 0.215 g / 0.00196098 mol = 109.63 g/mol (to two decimal places)

Answer: Broken line

Explanation:

When you collect data in an experiment, you usually need a model where you can analyze the data.

One way of doing this is when in an experiment you expect a given behavior determined by a function (or data obtained by previous investigations), you can graph your obtained data over the graph of the function (or previous data), and in this way, you can see if your data fits in the model.

You usually will graph your obtained data with dots, so usually, we graph the other things with a broken line. This is because if you use a colored line and you do some kind of fitting with your data, the lines may "clash" into each other, making the graph hard to read.

A bomb calorimeter is a device which is used to determine the change in enthalpy by measuring the change in temperature given the mass and heat capacity of the overall system by using the formula:

δh = m C (T2 – T1)

This is done by combusting the material in oxygen.

Hence the answer is:

measures δe for combustion reactions

A bomb calorimeter measures ΔE for combustion reactions. So correct option is B.

B) measures ΔE for combustion reactions.

A bomb calorimeter is a device used to measure the heat released or absorbed during a combustion reaction. It is a sealed container that is filled with oxygen and the reactants. The reaction is ignited, and the heat released is measured by the rise in temperature of the water surrounding the bomb.

The heat released in a combustion reaction is equal to the change in energy (ΔE) of the reaction. This is because the energy released is used to break the bonds in the reactants and form the bonds in the products. The heat released can be used to calculate the enthalpy change (ΔH) of the reaction, but only if the reaction is carried out at constant pressure.

Bomb calorimeters are used to measure the energy content of fuels, such as gasoline and coal. They are also used to measure the energy content of food.

The other options you have listed are incorrect. A bomb calorimeter does not measure ΔH for oxidation solutions, ΔH for hydrolysis solutions, ΔT for hydrolysis solutions, or ΔE for aqueous reactions.

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The complete question is:

Identify what a bomb calorimeter measures.

A) measures ΔH for reduction solutions

B) measures ΔE for combustion reactions

C) measures ΔH for aqueous solutions

D) measures ΔT for aqueous solutions

E) measures ΔE for oxidation reactions

The mass of silver metal produced when 6.35 g of copper reacts with excess silver nitrate is calculated to be 21.548 grams following a stoichiometric conversion process.

To calculate the mass of silver metal produced from the given mass of copper, we need to reference the balanced chemical equation for the reaction between copper and silver nitrate:

Cu (s) + 2AgNO3 (aq) → Cu(NO3)2 (aq) + 2Ag (s)

From the equation, we see that each mole of copper produces two moles of silver. We can conduct a series of conversions to find the mass of silver using the molar masses of copper (63.546 g/mol) and silver (107.868 g/mol).

Firstly, calculate the number of moles of copper:

moles of Cu = mass of Cu / molar mass of Cu

= 6.35 g / 63.546 g/mol

= 0.0999 mol

Then, using the stoichiometry of the reaction, calculate the moles of silver produced:

moles of Ag = 2 × moles of Cu

= 2 × 0.0999 mol

= 0.1998 mol

Finally, convert the moles of silver to mass:

mass of Ag = moles of Ag × molar mass of Ag

= 0.1998 mol × 107.868 g/mol

= 21.548 g

The mass of silver metal produced from the reaction is therefore 21.548 grams.

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it's density, because if you have a low carbon steel, which is not so dense, it's very pure due to the lack carbon content which increases the density. high carbon steel, which is used for guns, knives, swords, tools... etc... has a-lot of carbon content, which increases its density, because carbon is just really compact particles of decomposed matter, such as coal.

Answer:

solubility increases

Explanation:

Answer:

number of successful effective collisions is higher

adjacent is the correct answer

The angles ∠1 and ∠2 are adjacent to each other.

When the total of two angles equals 180 degrees, they are referred to as supplementary angles because they form a linear angle when combined. When the sum of two angles equals 90 degrees, they are considered to be complimentary angles, and they produce a right angle when they are combined.

In the given figure ∠1 and ∠2 are supplementary angle and adjacent to each other

Therefore in the options given  ∠1 and ∠2 are adjacent to each other.

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Answer: In this reaction, a precipitate is being formed.

Explanation:

A chemical change can be determined by the following indicators:

When magnesium ions and hydroxide ions react in aqueous state, it leads to the formation of a white colored solid of magnesium hydroxide.

In the above reaction, a precipitate is being formed and hence the reaction is considered as a precipitation reaction.

[tex]Mg^{2+}(aq.)+2OH^-(aq.)\rightarrow Mg(OH)_2(s)[/tex]

Therefore, in this reaction, the chemical change is that the precipitate is getting formed.

The half-life of scandium-46 is determined by noting that after 252 days, the mass of the isotope reduces from 12.0 g to 1.5 g, which is 1/8 of the original mass, indicating that three half-lives have passed. Dividing the total time by 3 gives us a half-life of 84 days for scandium-46.

To determine the half-life of scandium-46, we use the fact that after a certain number of half-lives, the remaining mass of a radioactive substance is half of its initial mass after each half-life period. In the given problem, a 12.0-g sample of scandium-46 decays to 1.5 g after 252 days. This decay represents a reduction to 1/8 of the original mass, indicating that three half-lives have passed (since 12.0 / 2 / 2 / 2 = 1.5).

Since 3 half-lives are equivalent to 252 days, we can find the length of a single half-life by dividing the total time by 3:

252 days ÷ 3 = 84 days

Therefore, the half-life of scandium-46 is 84 days.

A pure substance in chemistry is a material with a constant composition and unique set of properties, classified as either an element or a compound. Elements contain only one type of atom, while compounds consist of chemically bonded atoms of different types. Pure substances can be identified by their distinct physical properties and purity tests like chromatography.

In chemistry, a pure substance refers to materials that have a constant composition and a unique set of properties across the entire sample. Pure substances are classified into two categories: elements and compounds. An element is a pure substance that consists of a single type of atom and cannot be chemically broken down into simpler substances. Gold, oxygen, and copper are well-known examples of elements. On the other hand, compounds are pure substances that consist of two or more atoms chemically bonded together, such as water (H2O) which is made from hydrogen and oxygen. Unlike mixtures, compounds have fixed proportions of atoms and can only be separated into their constituent elements by chemical reactions.

Pure substances have distinct and consistent physical properties like melting and boiling points. In contrast, mixtures have variable compositions and may exhibit a range of melting and boiling points. Testing for purity can involve methods like chromatography, where a pure substance yields a single component, while impure substances produce multiple components.

Final answer:

To form one mole of Ca3P2, 120.234 grams of calcium are required based on the atomic mass of calcium and the stoichiometry of the compound.

Explanation:

To determine how many grams of calcium must be combined with phosphorus to form one mole of the compound Ca3P2, we need to first understand that Ca3P2 consists of 3 calcium (Ca) atoms and 2 phosphorus (P) atoms. The atomic mass of calcium is 40.078 amu (atomic mass units), and that of phosphorus is 30.973761 amu.

The total mass of calcium in Ca3P2 can be calculated as follows:

To convert this atomic mass to grams, we use the molar mass concept where 1 mole of any substance equals its atomic or molecular mass in grams. Therefore, we need:

To form one mole of Ca3P2, no information on the amount of phosphorus is needed since the question only asks for the amount of calcium required.

A substance in a solid phase is relatively rigid, has a definite volume and shape.

the answer is d because Solid substances have the lowest degree of freedom and the highest attractive and intermolecular forces between the molecules.

Answer:

15.63

Explanation:

C on edg :) just did the test

The molar mass of HgO is 216.59 g/mol. The molar mass of O2 is 32.00 g/mol. 15.63 moles HgO are needed to produce 250.0 g of Oxygen.

The term molar mass is defined as a compound is the mass in grams of one mole of the compound. In a substance, the amount of entities present e.g., atoms, molecules, ions, is called as a mole. A mole of any substance is 6.022 × 10²³ molecules.

Given that;

Molar mass HgO = 216.59 g/mol

The molar mass of O2 = 32.00 g/mol

250.0 g of Oxygen

Required moles of HgO

The balanced chemical equation is as follows:

2HgO → 2Hg + O2

250g Oxygen (1 mole O2/32.00 g/mol O2)(2 moles HgO/1 mol O2)

= 15.63 moles HgO

Thus, The molar mass of HgO is 216.59 g/mol. The molar mass of O2 is 32.00 g/mol. 15.63 moles HgO are needed to produce 250.0 g of Oxygen.

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Answer:

The correct answer is option B.

Explanation:

[tex]\frac{6}{42}=\frac{1}{7}[/tex]

A) [tex]\frac{4}{16}=\frac{1}{4}\neq \frac{1}{7}[/tex]

[tex]\frac{2}{21}=\frac{2}{21}\neq \frac{1}{7}[/tex]

Both fraction are not equivalent to [tex]\frac{1}{7}[/tex].

B)[tex]\frac{2}{14}=\frac{1}{7}= \frac{1}{7}[/tex]

[tex]\frac{3}{21}=\frac{1}{7}= \frac{1}{7}[/tex]

Both fraction are equivalent to [tex]\frac{1}{7}[/tex].

C) [tex]\frac{2}{14}=\frac{1}{7}= \frac{1}{7}[/tex]

[tex]\frac{4}{16}=\frac{1}{4}\neq \frac{1}{7}[/tex]

Both fraction are not equivalent to [tex]\frac{1}{7}[/tex].

D)[tex]\frac{7}{25}=\frac{7}{25}\neq \frac{1}{7}[/tex]

[tex]\frac{3}{21}=\frac{1}{7}= \frac{1}{7}[/tex]

Both fraction are not equivalent to [tex]\frac{1}{7}[/tex].