Describe the sampling method for determining population size

Answer:

Mercury is the only metal that's liquid at room temperature, bromine and iodine are the other

Explanation:

11 elements are gases

Others are solid

Answer:

Explanation:

the question is a bit confusing, but if i'm understanding correctly the answer is non-metals... some non-metals are gasses (all of the noble gasses), some are liquid (mercury and bromine), and some are solids (all the rest).

however, not all metals are solid at room temp, there are a few exceptions.

Answer:

According to Bohr's theory, an electron's path around the nucleus defines its

energy level.

Explanation:

It the certain energy by which the electrons have occupied there place in the orbitals. They can also be moved to the higher energy level by taking the energy from the surrounding. The emission of light can be seen when the electron falls from the higher energy state to the lower state. The orbital that is close to the atomic centre having the lowest energy level and the one that is found to be far away from the atomic centre has the highest energy level.

According to Bohr's theory, an electron's path around the nucleus defines its

d. Energy level.

It the specific energy by which the electrons have involved there place in the orbitals. They can likewise be moved to the higher energy level by taking the energy from the encompassing. The outflow of light should be visible when the electron tumbles from the higher energy state to the lower state. The orbital that is near the nuclear focus having the most reduced energy level and the one that is viewed as distant from the nuclear focus has the most noteworthy energy level.

Thus, correct option is d.

Find more information about Bohr's theory here:

brainly.com/question/18002213

Answer:

87.29×10²³ atoms

Explanation:

Nᴀ=6.02×10²³ (constant)

N=n×Nᴀ=14.5×6.02×10²³=87.29×10²³

Answer:

4d¹ electron has quantum numbers

n=4; l=2; ml= -2; ms= 1/2

Explanation:

There are 4 quantum numbers, namely

the principal quantum number (n)

the orbital angular momentum quantum number (l)

the magnetic quantum number (ml)

the electron spin quantum number (ms)

The principal quantum number describes the orbit or shell of the electron

here n = 4 ⇒ electron is in 4th shell

the orbital angular momentum quantum number describes the shape of orbital the electron is present in.

l= 0 ⇒ s-orbital

l= 1 ⇒ p-orbital

l= 2 ⇒ d-orbital

l= 3 ⇒ f-orbital

In our case l= 2 ⇒ p-orbital

ml specifies in which orbital electron is present of given shape

ml has 2l+1 values,which range from -1 to +l

here l = 2 ⇒ ml has 2(2)+1 = 5 values (-2 to +2)

so electron is present in one of the five d-orbitals

ms represents the spin of electron (+1/2 or -1/2)

If  +1/2 represents clockwise then -1/2 represents anti-clockwise and vice-versa.

⇒  4d¹ electron has quantum numbers

n=4; l=2; ml= -2; ms= 1/2.

An electron with quantum numbers n=4, l=2, ml=-2, ms=1/2 is located in the fourth energy level of an atom, within a 'd' shaped orbital pointing in a predetermined space direction, with an upward spin.

The student's question refers to a specific electron in an atom characterized by four quantum numbers: principal quantum number (n=4), azimuthal quantum number (l=2), magnetic quantum number (ml=-2), and spin quantum number (ms=1/2). These quantum numbers reveal the electron's energy level, shape, orientation in space, and spin direction, respectively.

Therefore, an electron with these quantum numbers is found in the fourth energy level (n=4) of an atom. The shape of the orbital where this electron is located is a 'd' orbital (l=2). The negative sign of the magnetic quantum number reveals that the orbital is oriented in one of the five spatial orientations possible for 'd' orbitals. Lastly, the spin quantum number of 1/2 means the electron's spin is up.

This shows the student's question is related to quantum mechanics studies in chemistry and physics, specifically atomic structure and electron configuration.

https://brainly.com/question/35385397

#SPJ3

Answer:

Forms ionic bonds, insoluble, doesn't participate in single or double displacement reactions, non-reactive, high heat of combustion

Explanation:

Beryllium is a metal, since it belongs to group 2A, the alkaline earth metals. It has a total of 2 valence electrons.

Phosphorus, on the other hand, belongs to group 5A and has a total of 5 valence electrons.

We have a compound which has a metal in it, therefore, it's an ionic compound. Beryllium, our metal, loses its 2 electrons to gain an octet and phosphorus, our nonmetal, should gain 3 electrons to have an octet. The oxidation states are +2 and -3 respectively. This means we need 3 beryllium cations and 2 phosphide anions in our formula [tex]Be_3P_2[/tex].

Beryllium phosphide would be expected to be insoluble, as only beryllium chloride, fluoride, nitrate, phosphate and sulfate are soluble substances, while the remaining ones are expected to be insoluble.

Due to its insolubility, beryllium phosphide would not participate in any ionic reactions, such as single displacement or double displacement.

Since it's insoluble, we expect this compound to be chemically stable and not reactive. This implies that if we wanted to burn it, the heat of combustion would be very high, as a lot of energy would be needed to be supplied in an endothermic reaction in order to burn it.

Answer:

The [tex]K_{sp}[/tex] remains the same

Explanation:

Let's look at what actually happens in this scenario. Before we dive into the explanation, remember the principle of Le Chatelier: for a system at equilibrium, a specific disturbance in molarity/volume/pressure of any species in equilibrium would cause the equilibrium to shift towards the side that minimizes such a disturbance.

To begin with, we have a saturated water solution of lead(II) chloride. A saturated solution means that at the given temperature we have a maximum amount of lead(II) chloride that could dissolve in the given volume of water.

Since lead(II) chloride is not highly soluble, we have an equilibrium between the precipitate and the dissociated ions:

[tex]PbCl_2(s)[/tex]⇄[tex]Pb^{2+}(aq)+2Cl^-(aq)[/tex]

Now we're adding NaCl to this solution. Sodium chloride is a sparingly soluble salt which readily dissociates into sodium and chloride ions:

[tex]NaCl(aq)\rightarrow Na^+ (aq)+Cl^- (aq)[/tex]

Notice that sodium chloride increases the concentration of chloride ions in the solution, so the equilibrium between the precipitate and its ions is disturbed.

According to the principle of Le Chatelier, due to an increase in chloride ions, the equilibrium would be disturbed and the system would tend to decrease it in order to restore the equilibrium. Hence, the equilibrium shifts towards the precipitate forming more of the precipitate and decreasing the amount of lead(II) cation, as well as the excess of chloride ions. This is also called the common ion effect: the common ion decreases the solubility of a salt.

However, it only decreases the solubility of the salt but not the solubility product constant defined as:

[tex]K_{sp}=[Pb^{2+}][Cl^-]^2[/tex]

A decrease in lead(II) concentration is compensated by the excess of chloride. The solubility product is only temperature-dependent, just as any other equilibrium constant, so it doesn't depend on the molarity of chloride or lead(II) ions.

Solubility, on the other hand, is equal to:

[tex]S=[Pb^{2+}]=\frac{K_{sp}}{[Cl^-]^2}[/tex]

And, as you can see, it decreases, as K is kept constant and we have an increase in chloride.

Answer:

26. Mass of sugar = 100 g

27. a).m/m % = 8.67 %

     b).m/m% = 20%

28.a). Mass of sugar = 12.5 g

     b).Mass of sugar = 12.5 g

     c).Mass of sugar = 30 g

Explanation:

26. Use formula:

[tex]m/m = \frac{mass\ of\ solute}{mass\ of\ solution} \times 100[/tex]

m/m = 20%

mass of solution = 500 g

mass of Solute = mass of sugar = ?

insert in the formula,

[tex]20 = \frac{mass\ of\ solute}{500} \times 100[/tex]

[tex]mass\ of\ solute = 20 \times 5[/tex]

mass of solute = 100 g

27. a)

[tex]m/m = \frac{mass\ of\ solute}{mass\ of\ solution} \times 100[/tex]

mass of Barium hydroxide(solute) = 13 g

mass of solution = 150 g

[tex]m/m = \frac{13}{150} \times 100[/tex]

m/m % = 8.67 %

b).

[tex]m/m = \frac{mass\ of\ solute}{mass\ of\ solution} \times 100[/tex]

mass of Glucose (solute) = 50 g

mass of solution = 250 g

[tex]m/m = \frac{50}{250} \times 100[/tex]

m/m% = 20%

28. a)

[tex]m/m = \frac{mass\ of\ solute}{mass\ of\ solution} \times 100[/tex]

m/m% = 5

mass of solution = 250 g

mass of solute = ?

[tex]mass\ of\ solute= \frac{mass\ of\ solution}{100} \times m/m[/tex]

[tex]mass\ of\ solute= \frac{250}{100} \times 5[/tex]

mass of sugar = 12.5 g

b).

m/m% = 2.5%

mass of solution = 500 g

mass of solute = ?

[tex]mass\ of\ solute= \frac{mass\ of\ solution}{100} \times m/m[/tex]

[tex]mass\ of\ solute= \frac{500}{100} \times 2.5[/tex]

mass of sugar = 12.5 g

c).

m/m% = 3 %

mass of solution = 1 kg = 1000 g

mass of solute = ?

[tex]mass\ of\ solute= \frac{1000}{100} \times 3[/tex]

Mass of sugar = 30 g

Answer:

D. a very fast run

Explanation:

Fermentation :

The second step of anaerobic respiration is fermentation. It involve the fermentation of pyruvate into lactic acid or alcohol depending upon the organism in which it is taking place. There is no ATP produced, however carbon dioxide is released in this step.

Anaerobic respiration in plants:

Anaerobic respiration in plants produced ethanol which if accumulate then cause the harmful effect in plants. It is also occur in some microorganisms such as yeast.

C₆H₁₂O₆  →   2C₂H₅OH  + 2CO₂

Anaerobic respiration in animals:

Anaerobic respiration in animals pyruvate converted into lactic acid and it is not as harmful as ethanol in plant if accumulate. It is produced during exercise because oxygen is not supplied to muscles. It can produce the cramps which can be cured with massage.

C₆H₁₂O₆  →   2C₃H₆O₃

Answer:

Cells

Explanation:

High-powered microscopes are used in order to see microscopical (extremely small) structures of objects that cannot be seen with a naked eye.

When we look at a leaf, we will see the composition of it and the structural patterns that we couldn't see clearly or at all without a microscope.

Leaves consist of cells and spores (stomata) between the cells. Using a microscope will enable us to see them.

Answer:

A chemical equation can be described as a symbolic representation of a chemical reaction. It can be written in the form of words or symbols.

The following chemical reaction can be completed as :

Na2SO4·10H2O + 2C = Na2S + 10H2O + 2CO2

Sodium Sulfate Decahydrate + Diamond = Sodium Sulfide + Water + Carbon Dioxide

The products of the reaction are:

Answer:

It determines the maximum amount of the product that can be formed

Explanation:

Usually when performing a chemical reaction, it is hard to measure the exact amounts of the two reactants to react completely. This is why generally we take one reactant as our limiting reagent and another reagent in excess.

The reactant that is limiting reacts completely, while the reactant in excess still remains in a solution after reaction is over.

The importance of the limiting reactant is huge: it determines the maximum amount of the product that can be formed. It's limiting and, therefore, the extent of the reaction depends on how much of the limiting reagent we have. According to stoichiometry, we find the moles of a product formed directly from the limiting reagent, while the reagent in excess doesn't provide any relevant information.

A limiting reactant is a reactant that is used up first in a chemical reaction and determines the maximum amount of product that can be created. It is important in stoichiometry for calculating theoretical yields and ensuring the efficient and safe use of reactants.

A limiting reactant in a chemical reaction is the substance that is totally consumed first and hence determines the amount of product formed. The importance of a limiting reactant in stoichiometry lies in its role in predicting the theoretical yield of a reaction. When reactants are not present in perfect stoichiometric ratios as indicated by the balanced chemical equation, one will be exhausted before the others, thus limiting the formation of the product. This reactant is the limiting reagent, and the remaining substances are considered to be in excess.

An important aspect of stoichiometry is performing mass-mass calculations to establish how much product can be produced based on the amount of the limiting reactant. Understanding which reactant will be consumed first is crucial for evaluating a chemical process, ensuring safety (such as in the case of the space shuttle's fuel), and optimizing resource usage. Alternatively, identifying the limiting reactant can be approached by calculating the expected amount of product from the complete reaction of each reactant and comparing which yields the least amount of product.

Answer:

Mass = 2.222 g

Explanation:

Given data:

Volume of  neon gas = 2.56 L

Temperature = 273 K

Pressure = 1 atm

Mass of neon gas = ?

Solution:

PV = nRT

n = PV / RT

n = 1 atm × 2.56 L/ 0.0821 atm. L / mol. K× 273 K

n = 2.56 L.atm / 22.4 atm. L/ mol

n = 0.11 mol

Mass = number of moles × molar mass

Mass = 0.11 mol × 20.2 g/mol

Mass = 2.222 g

Answer:the volume will be doubled

Explanation: the expression from the question clearly indicates Charles' law. Charles' law states that volume is proportional to temperature at constant pressure. This simply means as one variable increase, the other variable will also increase. Please see attachment for mathematical explanation

Answer:

56.44 %

Explanation:

The formula of copper(II) sulfate pentahydrate is [tex]CuSO_4\cdot 5H_2O[/tex].

In order to calculate the mass percentage of water in it, we may assume that we have 1 mol of copper(II) sulfate pentahydrate. In general, the mass percentage is a ratio between the mass of a component and the total mass of the compound expressed in percent:

[tex]\omega = \frac{m_c}{m_t}\cdot 100 \%[/tex]

Since we're taking 1 mole of a substance here, we may state that the mass percentage of water will be calculating using molar masses instead:

[tex]\omega_{H_2O} = \frac{5M_{H_2O}}{M_{CuSO_4\cdot 5 H_2O}}\cdot 100 \%[/tex]

Notice that we take 5 molar masses of water, as 1 mole of copper(II) sulfate pentahydrate contains 5 moles of water molecules, then:

[tex]\omega_{H_2O} = \frac{5\cdot 18.016 g/mol}{159.609 g/mol}\cdot 100 \% = 56.44 \%[/tex]

3CaCl₂ + 2Na₃PO₄→ Ca₃(PO₄)₂ + 6NaCl

We are given the Equation;

CaCl₂ + Na₃PO₄→ Ca₃(PO₄)₂ + NaCl

Assuming the question requires us to balance the equation;

In this case;

3CaCl₂ + 2Na₃PO₄→ Ca₃(PO₄)₂ + 6NaCl

Answer:

P₂ = 800 torr

Explanation:

Given data:

Initial Volume = 4 L

Initial Temperature = 47°C (47+273= 320 K)

Initial pressure = 800 torr

Final volume = 2000 mL (2000/1000 = 2 L)

Final temperature = -113°C (-113+273 =160 K )

Final pressure = ?

Solution:

Formula:  

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

P₂ = P₁V₁ T₂/ T₁ V₂  

P₂ = 800 torr × 4 L × 160 K / 320 K × 2 L  

P₂ = 512000 torr .L. K / 640 k.L

P₂ = 800 torr

The new pressure of the confined gas is 800 torr.

The new pressure of the gas is calculated by applying general gas equation as shown below;

[tex]\frac{P_1V_1 }{T_1} = \frac{P_2 V_2}{T_2} \\\\P_2 = \frac{P_1V_1 T_2}{T_1V_2}[/tex]

where;

The new pressure of the confined gas is calculated as follows;

[tex]P_2 = \frac{800 \times 4 \times 160}{320 \times 2} \\\\P_2= 800 \ torr[/tex]

Thus, the new pressure of the confined gas is 800 torr.

Learn more about gas equation here: https://brainly.com/question/4147359

Answer:

Tropical rain forest environments

Explanation:

Answer:

Imma Explanation:

Answer:

The correct option is B)  a gradual change of the traits of a species over time

Explanation:

The theory of natural selection explains the gradual changes which occur in the population of a species over time. According to natural selection, those organisms which are better adapted to live in an environment survive and pass on their traits to their offsprings. As a result, the traits of a species tend to change over time through the process of evolution. Evolutionary changes do not occur rapidly, instead, they can take many years to occur.

Answer:

1.087 mi/min

Explanation:

Given data:

Speed of car in Km/h = 105

Speed of car in miles/min = ?

Solution:

It is given that one miles = 1.61 Km

while it is known that one hour = 60 minutes

Thus in order to convert the km/h into mi/min we will divide the given value by 96.561.

105 / 96.561

1.087 mi/min

Answer:

sea floor spreading

Explanation: hfhgg

Answer:

option C = 9.0 x 10²³ atoms

Explanation:

Data Given:

no. of moles of tin (Sn) atoms = 1.5 moles

no. of tin (Sn) atoms = ?

Solution:

Formula used to find number of atoms

                  no. of moles = no. of atoms / Avogadro's number

Rearrange the above equation:

          no. of atoms =   no. of moles x Avogadro's number . . . . . . (1)

Where

Avogadro's number = 6.022 x 10²³

Put values in equation 1

           no. of atoms = 1.5 x 6.022 x 10²³

           no. of atoms = 9.033 x 10²³

Round the figure = 9.0 x 10²³ atoms

So option C is correct

Answer:

a carboxylic acid and an amine

Explanation:

A functional group is an atom or group of atoms inside a molecule that has comparable chemical properties anytime it appears in numerous compounds. When other parts of the molecule are not similar, some functional groups react in certain manners.

Carboxylic acid is a carbonyl-containing functional group, with carbon atom bonded to an hydroxyl group on one side and on the other side is either a carbon or hydrogen atom.  

An amine group is composed of a nitrogen atom bonded to a combination of carbon and hydrogen atoms.

The number of electron pairs around a central atom determines the molecule's molecular geometry, which is based on the VSEPR theory. By counting the total electron pairs (both bonding and lone pairs), one can use a reference table to predict the geometry of the molecule.

The number of electron pairs around a central atom is determined by the molecule's Lewis structure, which includes both bonding pairs (BP) and lone pairs (LP). This number is often referred to as the Steric Number (SN) or Electron Group Geometry. The basic molecular geometry depends on the count of these electron pairs and their arrangement to minimize repulsions, following a specified shape determined by the VSEPR (Valence Shell Electron Pair Repulsion) theory.

To determine the molecular geometry, one must:

Count the total number of electron pairs (bonding and lone) around the central atom.

Determine the geometry of the molecule using a reference table that correlates the number of electron pairs to geometrical shape.

For example, a molecule with three electron groups around the central atom which includes two double bonds and one lone pair initially adopts a trigonal planar arrangement to minimize repulsion. However, the presence of a lone pair can adjust the actual molecular geometry from this initial layout.

Answer:

P = 22000 kg. m/s

Explanation:

Given data;

Mass of elephant = 2000 Kg

Velocity = 11 m/s

Momentum = ?

Solution:

Momentum is the product of mass and velocity of an object.

It can be calculated from given formula:

P = mv

P = momentum

m = mass

v = velocity

Now we will put the values in formula.

P = 2000 Kg × 11 m/s

P = 22000 kg. m/s

Answer:

3.011 × 10²³ particles

Explanation:

Given data:

Number of moles = 0.5 mol

Number of particles = ?

Solution:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

one mole of substance =  6.022 × 10²³ particles

For 0.5 mole of substance:

0.5 mol × 6.022 × 10²³ particles / 1 mol

3.011 × 10²³ particles