Which statement best describes a mechanical wave?

Explanation:

the investigation lasts for 7 days.

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The biological Oxygen demand of the lake is increased by 1.5 ton.

Discussion:

The reaction of methanol with Oxygen is as follows;

In the reaction above; Since Methanol, CH3OH and Oxygen, O2 have the same molar mass; 32.

Therefore we can say since;

2 moles of CH3OH requires 3 moles of O2.

Therefore, 1 ton of methanol will require 1.5 ton of oxygen.

The biological Oxygen demand of the water is therefore increased by 1.5 ton as this is the amount of Oxygen consumed by the ethanol.

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Explanation:

BaF2(s) <------> Ba2+(aq) + 2F-(aq)

Ksp BaF2 =  1.0 x 10^-6.

Ksp BaF2 = [Ba2+(aq)]×[F-(aq)]^2 at equilibrium

When Qsp >Ksp, BaF2 will precipitate

Qsp = [Ba2+(aq)]×[F-(aq)]^2

[Ba2+(aq)]×[F-(aq)]^2 > 1.0 x 10^-6.

0.0122 moldm-3 × [F-(aq)]^2 > 1.0 x 10^-6

[F-(aq)]^2 > 1×10^-6 / 0.0122 mol2dm-6

[F-(aq)]^2 > 81.96 × 10^-6 mol2dm-6

[F- (aq)] > 9.05 × 10^-3 moldm-3

So F- concentration should be more than 9.05 × 10^-3 moldm-3

Using Hess's law we found:

1) By adding reaction 10.2 with the reverse of reaction 10.1 we get reaction 10.3:

KOH(aq) + HCl(aq)  → H₂O(l) + KCl(aq)   ΔH  (10.3)

2) The ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy (ΔH).    

The reactions of dissolution (10.1) and neutralization (10.2) are:

KOH(s) → KOH(aq)   ΔHsoln    (10.1)

KOH(s) + HCl(aq) → H₂O(l) + KCl(aq)     ΔHneut     (10.2)

1) According to Hess's law, the total change in enthalpy of a reaction resulting from differents changes in various reactions can be calculated as the sum of all the enthalpies of all those reactions.      

Hence, to get reaction 10.3:

KOH(aq) + HCl(aq) → H₂O(l) + KCl(aq)    (10.3)

We need to add reaction 10.2 to the reverse of reaction 10.1

KOH(s) + HCl(aq) + KOH(aq) → H₂O(l) + KCl(aq) + KOH(s)

Canceling the KOH(s) from both sides, we get reaction 10.3:

KOH(aq) + HCl(aq)  → H₂O(l) + KCl(aq)    (10.3)

2) The change in enthalpy for reaction 10.3 can be calculated as the sum of the enthalpies ΔHsoln and ΔHneut:

[tex] \Delta H = \Delta H_{soln} + \Delta H_{neut} [/tex]

The enthalpy of reaction 10.1 (ΔHsoln) changed its sign when we reversed reaction 10.1, so:

[tex] \Delta H = \Delta H_{neut} - \Delta H_{soln} [/tex]

Therefore, the ΔHsoln must be subtracted from ΔHneut to get the total change in enthalpy ΔH.

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Answer:

The key to understanding why ionic and covalent compounds have different properties from each other is understanding what's going on with the electrons in a compound. Ionic bonds form when atoms have different electronegativity values from each other. When the electronegativity values are comparable, covalent bonds form.

But, what does this mean? Electronegativity is a measure of how easily an atom attracts bonding electrons. If two atoms attract electrons more or less equally, they share the electrons. Sharing electrons results in less polarity or inequality of charge distribution. In contrast, if one atom attracts bonding electrons more strongly than the other, the bond is polar.

Ionic compounds dissolve in polar solvents (like water), stack neatly on each other to form crystals, and require a lot of energy for their chemical bonds to break. Covalent compounds can be either polar or nonpolar, but they contain weaker bonds than ionic compounds because they are sharing electrons. So, their melting and boiling points are lower and they are softer.

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Answer:

0.86

Explanation:

1mol of Zn has mass of 65.39g.The amount of Zn is 2.5g65.39g/mol=0.038mol.

The amount of H2 produced is the same as the amount of Zn consumed (0.038mol).

1mol of ideal gas will occupy 22.4L at STP.

The H2 will occupy 0.038mol×22.4L/mol=0.86L

.

According to the equation given, we have N2 + 3H2 → 2NH3.

Therefore, to determine the moles of NH3 we have to do the following-

1.3 mol H2 × 2 mol NH3 / 3 mol H2 = 0.87 mol

Answer: .87 moles of NH3 are produced from 1.3 moles of H2.

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Answer:

100.0

Explanation:

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Waste is removed from the body in various ways. Kidneys filter out metabolic waste, excess fluid and eliminate it in the form of urine. Lungs exhale CO2 from the deoxygenated blood. The undigested solid waste is egested out from the large intestine. Excretion is the process of removing wastes and excess water from the body. It is one of the major ways the body maintains homeostasis. Organs of excretion make up the excretory system. They include the kidneys, large intestine, liver, skin, and lungs.

Answer:

dog dog im not gon hold u we kinda screwed

This problem is describe the mole-ratio composition of an allow composed by tin, lead and cadmium. Ratios are given as Sn:Pb 2.73:1.00 and Pb:Cd is 1.78:1.00, and we are asked to calculate the mass percent compositon of Pb in the allow.

In this case, according to the given information, it turns out possible realize that the following number of moles are present in the alloy, according to the aforementioned ratios:

[tex]2.73mol Sn\\\\1.00molPb\\\\\frac{1.00molPb*1.00molCd}{1.78molPb}= 0.562molCd[/tex]

Next, we calculate the masses by using each metal's atomic mass:

[tex]m_{Sn}=2.73mol*\frac{118.7g}{1mol}=324.05g\\\\ m_{Pb}=1.00mol*\frac{207.2g}{1mol}=207.2g\\\\m_{Cd}=0.562mol*\frac{112.4g}{1mol}=63.2g[/tex]

Thus, the mass percent composition of each metal is shown below:

[tex]\%Sn=\frac{324.05g}{324.05g+207.2g+63.2g} *100\%=54.5\%\\\\\%Pb=\frac{207.2g}{324.05g+207.2g+63.2g} *100\%=34.9\%\\\\\%Cd=\frac{63.2}{324.05g+207.2g+63.2g} *100\%=10.6\%[/tex]

So that of lead is 34.9 %.

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Answer:

Ba(OH)2 + 2 HCl → BaCl2 + 2 H2O

The reactants are present in equimolar amounts, so there is no excess or limiting reactants.

(0.0500 L) x (0.600 mol/L HCl) x (2 mol H2O / 2 mol HCl) = 0.0300 mol H2O

(4.184 J/g·°C) x (50.0 g + 50.0 g) x (25.82 - 21.73)°C = 1711.256 J

(1711.256 J) / (0.0300 mol H2O) = 57042 J/mol = 57.0 kJ/mol H2O

Explanation:

Answer:

a.2.55e-7

b.6830

Explanation:

Answer:

i dont speak mexican

Explanation:

Answer: The following information should be included;

What is the difference between the greenhouse effect, climate change and global warming?

What proof do we have that climate change is happening?

Why is it happening?

Since gas molecules average velocity depends on temperature, oxygen molecules at 25°C are moving faster than oxygen molecules at 0 °C.

According to the kinetic theory of gases, the molecules of a gas are in constant random motion and collide frequently with each other and the walls of the container.

The average speed of gas molecules depends on temperature and molar mass as shown by the relation;

vrms = √3RT/M

The following statement are true among the options provided;

The following are false among the options provided;

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Answer:

1. An independent variable is manipulated, or changed. The dependent, or responding variable, changes based on the independent variable. The dependent variable is examined.

2. It is a controlled experiment.

Explanation:

In a controlled experiment all variables are kept the same, except for the one being tested, which is called the experimental variable , or independent variable . This group is the experimental group . The group that is not affected by the experimental variable is the control group .

Very often a graph will be used to analyze the results of the experiment. The independent/experimental variable is placed on the x-axis and the dependent variable is placed on the y-axis. The dependent variable is what is measured as a result of the application of the experimental variable.

A variable that is independent is altered. Based on the independent variable, the responding variable, or dependent variable, alters. Examining the dependent variable. The experiment is carefully controlled.

In mathematical modeling, statistical modeling, and experimental sciences, there are dependent and independent variables. Dependent variables get their name because, during an experiment, their values are investigated under the presumption or requirement that they are dependent on the values of other variables due to some law or rule.

A variable that is independent is precisely what it sounds like. It is a stand-alone variable that is unaffected by the other variables you are attempting to assess. Age, for instance, could be an independent variable.

When doing an experiment, the independent variable is what you alter, and the dependent variable is what changes as a result of that change. This is an easy way to conceive of independent and dependent variables.

Thus, based on the independent variable, the responding variable, or dependent variable, alters.

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Answer:

Explanation:

The required pressure can be found by using the formula for Boyle's law which is

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

where

P1 is the initial pressure

P2 is the final pressure

V1 is the initial volume

V2 is the final volume

From the question we have

[tex]P_2 = \frac{1 \times 196}{26} = \frac{196}{26} \\ = 7.538461...[/tex]

We have the final answer as

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Answer:The plates are not fixed but are constantly moving atop a layer of solid and molten rock called the mantle. The Ring of Fire is a string of volcanoes and sites of seismic activity, or earthquakes, around the edges of the Pacific Ocean. ... A hotspot is a place in the middle of a tectonic plate where hot magma rises.

Explanation:

Answer:

Every germanium atom is tetrahedrally linked to four sulphur atoms, with an interatomic distance of 2.19A. The angle between the two sulphur bonds is 103°.

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An interatomic distance of 2.19A exists between each germanium atom and the four sulphur atoms that are tetrahedrally connected to it. The two sulphur bonds form a 103° angle.

A complex molecule's or ion's bond angle is the angle between the two bonds, or the angle between two orbitals that contain bonding electron pairs surrounding the central atom. It is determined using a spectroscopic approach and measured in degrees.

Any angle between two bonds that share an atom is known as a bond angle, and it is often measured in degrees. The distance along the straight line between the nuclei of two bound atoms is known as a bond distance.

Bond angles also have a role on a molecule's structure. The angles between neighboring lines that form bonds are known as bond angles. The difference between linear, trigonal planar, tetrahedral, trigonal-bipyramidal, and octahedral crystals may be determined by the bond angle.

Thus,  The two sulphur bonds form a 103° angle.

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This  problem provides the molar mass and radius of a metal that has an FCC unit cell and the density is required.

Firstly, we begin with the formula that relates the aforementioned variables and also includes the Avogadro's number and the volume of the unit cell:

[tex]\rho=\frac{Z*M}{V*N_A}[/tex]

Whereas Z stands for the number of atoms in the unit cell, M the molar mass, V the volume and NA the Avogadro's number. Next, since FFC is able to hold 4 atoms and M and NA are given. Next, we calculate the volume of the atom in the unit given the radius in meters:

[tex]V=a^3=(2*1.92x10^-10m*\sqrt{2} )^3=1.60x10^{-28}m^3/atom[/tex]

And finally the required density in g/cm³:

[tex]\rho=\frac{4*241.5g/mol}{1.60x10^{-28}m^3/atom*6.022x10^{23}atom/mol} \\\\\rho=10025739g/m^3=10.03 g/cm^3[/tex]

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The heat produced by 4.5 moles of magnesium when burnt is 2700 kJ.

A thermochemical reaction is a reaction in which the amount of heat lost or gained is included in the reaction equation. The thermochemical reaction equation for the combustion of magnesium is shown as follows;

2 Mg(s) + O2(g) → 2 MgO(s) + 1200 kJ

From the reaction equation;

2 moles of magnesium produced 1200 kJ of heat

4.5 moles of magnesium will produce 4.5 moles × 1200 kJ/2 moles

= 2700 kJ

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Answer:

A mixture of chlorine gas (Cl2) and fluorine gas (F2):

✔ London dispersion forces

Explanation:

SO2 acts both as an oxidizing and a reducing agent depending on the conditions of the reaction. It also leads to acid rain.

The reaction of HCl with Na2SO3 occurs as follows;

Na2SO3 + 2HCl ------> 2NaCl + SO2 + H2O

The gas evolved in the reaction is SO2. It is liberated because sulfites react with acids to liberate sulfur IV oxide.

The ionic equation of the reaction is; [tex]SO3^2-(aq) + 2H^+(aq) ----> SO2(g) + H2O(l)[/tex]

The reaction of SO2 with Lugol solution occurs as follows;

SO2 +I2 + 2H20→ H2SO4 + 2HI. This demonstrates oxidation because sulfur is oxidized from +4 to +6 state from left to right. This shows SO2 as a reducing agent.

With H2S, the gas reacts as follows;

2H2S + SO2 → 3S (s) + 2H2O

The oxidation number of sulfur decreases from +4 to zero. This demonstrates the gas as an oxidizing agent. SO2 can act as oxidizing or reducing agent because it can change its oxidation state to +6(oxidation) by electron loss or gain electrons to decrease its oxidation state as low as -2.

The gas SO2 is an acid gas. It dissolves in water to yield an acid solution. Also SO2 is a bleaching agent. The major environmental impact of SO2 is that it leads to acid rain as follows; 2SO2 + O2 + 2H2O⇌2H2SO4.

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Taking into account the definition of pH and pOH, the [H⁺] is 3.16×10⁻⁵ M and the solution will be acid.

First of all, pH is a measure of acidity or alkalinity that indicates the amount of hydrogen ions present in a solution or substance.

The pH is defined as the negative base 10 logarithm of the activity of hydrogen ions, that is, the concentration of hydrogen ions or H₃O⁺:

pH= - log [H⁺]= - log [H₃O⁺]

Similarly, pOH is a measure of hydroxyl ions in a solution and is expressed as the logarithm of the concentration of OH⁻ ions, with the sign changed:

pOH= - log [OH⁻]

The following relationship can be established between pH and pOH:

pH + pOH= 14

In this case, being pOH= 9.50, pH is calculated as:

pH + 9.40= 14

pH= 14 - 9.50

pH= 4.50

Replacing in the definition of pH the concentration of H⁺ ions is obtained:

- log [H⁺]= 4.50

Solving :

[H⁺]= 10⁻⁴ ⁵

[H⁺]= 3.16×10⁻⁵ M

The numerical scale that measures the pH of the substances includes the numbers from 0 to 14, being acidic solutions with a pH lower than 7, and basic those with a pH greater than 7. The pH = 7 indicates the neutrality of the solution.

In this case, the pH has a value of 4.50. So, the solution is acidic.

In summary, the [H⁺] is 3.16×10⁻⁵ M and the solution will be acid.  

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Answer:

by finding the slope of tangent (y2 - y1)/(x2 - x1)

Yes according to reliable sources.

Answer:

1.345.0

Explanation:

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