GIVING BRAINLY AND 20 POINTS

A sound wave in air has the wavelength of 1.36 m. Calculate its frequency? Assume the speed is 340 m/s.

(a) Van der Waal's forces. Van der Waal's forces are weak electrostatic interactions between non-polar molecules.

These weak forces arise from the fluctuating dipoles within the molecules, which cause temporary charges to develop and attract each other. This attraction leads to the formation of weak intermolecular bonds, which are mainly responsible for the attraction between non-polar molecules. These forces are weak in comparison to other intermolecular forces, such as hydrogen bonding and ionic bonds, but are still important for the stability of non-polar molecules and their ability to dissolve in other non-polar solvents.Van der Waals forces are attractive intermolecular forces between molecules caused by the fluctuating dipole moments of molecules.

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complete question:The attraction that non-polar molecules have for each other is primarily caused by —

(a) Van der Waal's forces (b) Difference in electronegativities

(c) Hydrogen bonding (d) High ionisation energy​

The number of grams of water in the sample if 517J of heat is added to a sample of liquid water is 3.481g.

The mass of a substance can be calculated using the following formula;

Q = mc∆T

Where;

According to this question, 517J of heat is added to a sample of liquid water, the temperature rises from 23.0°C to 58.5°C. The mass can be calculated as follows;

517 = m × 4.184 × {58.5°C - 23.0°C}

517 = 148.532m

m = 3.481grams.

Therefore, the mass of the water sample is 3.481g

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pH = pKa + log [conj.base]/[acid]

Let the concentration of the conjugate base = x

=> The concentration of the acid is also x (As the acid concentration is equivalent to that of the conjugate base)

for CH₃COOH=0.50 M and CH₃COO=0,25 M

pH = pKa + log [salt]/[acid]

pKa = -log Ka = -log 1.8x10-5 = 4.74

pH = 4.74 + log (0.50 M/1.0 M) = 4.74 + log 0.5 = 4.74 + (-0.3)

pH = 4.74 - 0.3

pH = 4.44

For0.20 M Na2CO3

pH=−log[H+]

    =−log (1.54×10−12)

   =11.8

for HNO₂

Kb = 2.17X10^-11 = x^2 / 0.148

x = [OH-] = 1.79X10^-6

pOH = 5.747

pH = 14.000 - pOH = 8.253

​

for HPO₄³⁻

= [HPO₄³⁻] [PO₄³⁻] [H +]/×10⁻³

=[PO₄³⁻]5.464×10⁻¹⁸

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1) We could use the bromine water test to tell the difference between the alkane and the alkene

2) We can use a detergent to wash a cloth that is contaminated by oil.

The term alkane has to do with a hydrocarbon that is composed of only a straight chain compound there are no multiple bonds in the alkane molecule and this is the difference between the alkane and the alkene. The alkene is composed of double bonds. The alkene compounds are able to decolorize bromine water while the alkanes can not.

If you have a contaminated cloth, you can be able to wash it by the use of a detergent because it is able to lift off the grease or oil by the use of the hydrophobic tail of the detergent.

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Answer:

1. The dissolving is endothermic and deltaH is positive

2. A. The bonds in the reactants are stronger than in the products and deltaH is positive

3. I can't see the diagram so I don't know the answer (it's a glitch on my part not yours, my school district blocks images automatically on their rented chromebooks)

4.  A. I, and II only

Explanation:

   When we measure the temperature of a solution, and we notice that the temperature of the water is decreasing, then this is an endothermic reaction..

   The dissolved solute (the "invisible" ions) are absorbing the heat, causing the water around it to be colder.. **Heat moves from hot to cold, so the water is losing it's heat and the dissolving (dissolved solute) is gaining heat, meaning that it is Endothermic.

    When a reaction is endothermic, the energy that is required to break bonds and attractive forces is greater than the energy required to form bonds and attractive forces. This means that the bonds in the reactants are stronger than in the products and deltaH is positive. Since we know that the energy in the reactants is greater, there is more heat in the reactants. This is also why the dissolved solute would be gaining heat.. If the energy of the reactants is stronger, when it breaks, it will release a lot of energy that the dissolved solute will be absorbing.

     Think, heat (q, released or absorbed) is measured in Joules, the higher the Joules, the hotter something will be. So, if the heat (q) is negative, that represents the amount of Joules (heat) being released.  If it is positive, that is the amount being absorbed. So, if heat is being absorbed then deltaH is positive.  

    If the diagram shows the products being at a higher energy level than the reactants, then the diagram shows an endothermic reaction.. If we see that the energy from the products is greater, than the energy of the system increased as it absorbed energy from its surroundings.

If the diagrams shows the reactants being at a higher energy level than the products, then the diagram shows an exothermic reaction.. Think of it this way, if we see that the energy from the reactants was greater, than the energy of the system was originally greater than the surroundings, but now (observing the products), it is not, as energy was lost to the surroundings, making this an exothermic reaction.

    For exothermic reactions, the energy that is required to break bonds and attractive forces is less than the energy required to form bonds and attractive forces.. This means that energy in the products are greater, so as these bonds are broken and energy is released, the surroundings gain energy/heat. This means that the energy is favorable (more stable), the more negative our potential energy (energy of the system) is, the more favorable our process is.

Answer:

b. decreases

Explanation:

Static equilibrium involves the sensation of linear acceleration as well as changes in head rotation is  False

A system is said to be in a condition of static equilibrium when all of its parts are at rest and there should be no net force operating on it.

Therefore, The macula is an oval-shaped region close to the retina's center. The layer that lines the back of the eye and is light-sensitive is called the retina. It is only 0.2 millimeters thick and has 200 million neurons.

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See full question below

Static equilibrium involves the sensation of linear acceleration as well as changes in head rotation.

T/F

A surfer rides an ocean wave is fluid friction

A bowling ball travels down a bowling lane rolling friction

A baseball flies through the air is air resistance

A hose rests on the edge of a truck is static friction.

Friction is described as the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other.

Static friction is that force that keeps an object at rest.

It is that  friction experienced when individuals try to move a stationary object on a surface, without actually triggering any relative motion between the body and the surface on which it is on.

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Complete question:

dentify the type of friction acting in each scenario.

A surfer rides an ocean wave.

A bowling ball travels down a bowling lane.

A baseball flies through the air.

A hose rests on the edge of a truck.

OPTIONS:

air resistance

fluid

rolling

sliding

static

Answer:

The number of electron in neutral atom of nitrogen are 7.

Atomic mass = 14 amu

Explanation:

An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.

All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.

The number of electron in neutral atom of nitrogen are 7.

Thus its atomic number is also 7.

Atomic mass = number of proton + number of neutron

Atomic mass = 7 + 7

Atomic mass = 14 amu

Answer:

1.3 moles

Explanation:

pv = nrt

n = pv/rt

n = (125 * 25) / (8.3144598 * 289)

n = 1.3 moles

Answer:

B : 0.133 M

Explanation:

moles Li3N3 = 0.4 mol Li x (2 moles Li3N/6 moles Li) = 0.133 M

Answer:

Its a compound :PP

Explanation:

have a good day

Answer:

Compound

Explanation:

Answer: There are 0.307 moles of molecules in 35 g of octane.

Explanation: You start by finding the molar mass of octane,(C8H18)This is 114 grams, because there are eight moles of carbon atoms and eighteen moles of hydrogen atoms in each mole of octane molecules.So, we total up 8 x 12 (for the carbon) and 18 x 1 (for the hydrogen).35g÷114 9g. That's it! This answer is the number of moles of octane molecules contained in the 35 grams of the compound.

-------

mol

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 5.05×10²⁴ particles are in 8.4 mole of octane.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity of amount of substance. It measure the number of elementary entities of a given substance that are present in a given sample. There are so many formula for calculating mole.

we know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number

number of atoms/molecules/particles=number of moles × 6.022×10²³(Avogadro number)

number of moles of octane= 8.4 moles

Substituting all the given values in the above equation, we get

number of atoms/molecules=8.4 × 6.022×10²³

number of atoms/molecules=5.05×10²⁴ particles

Therefore, 5.05×10²⁴ particles are in 8.4 mole of octane.

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Chemical reactions like Canizzaro reaction involves  a chemical reaction which involves base-induced disproportionation of two molecules of  non-enolizable aldehyde to give a primary alcohol and a carboxylic acid while Stephen reaction involves the preparation of aldehydes from nitriles using tin(II) chloride,hydrochloric acid and quenching the resulting iminium salt with water.

Chemical reactions are defined as reactions which occur when a substance combines with another substance to form a new substance.Alternatively, when a substance breaks down or decomposes to give new substances it is also considered to be a chemical reaction.

There are several characteristics of chemical reactions like change in color, change in state , change in odor and change in composition . During chemical reaction there is also formation of precipitate an insoluble mass of substance or even evolution of gases.

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Answer:

A

Explanation:

The weak base ionization constant (Kb) for \(C_{4} H_{4} N_{2}\) is equal to Option A.

A weak foundation is a base that makes ionize only slightly in an aqueous solution. Remember that a foundation can be defined as an object, which receives a hydrogen ion from another object.

To obtain an aqueous solution of a weak acid, the dissociation constant is called the acid ionization constant (Ka). Similarly, the constant equilibrium of a weak base reaction with water is the base ionization constant (Kb). In any conjugate acid-base pair, KaKb = Kw.

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MnO4- + 4e- → MnO2 + 2H2O Now the half-equation is balanced in alkaline medium.

To balance the half-equation MnO4- → MnO2 in alkaline medium, we need to follow the steps for balancing redox reactions in basic solution. The goal is to balance the number of atoms and charges on both sides of the equation.

Start by balancing the atoms other than oxygen and hydrogen. In this case, we only have manganese (Mn) atoms. There is one Mn atom on both sides, so the Mn atoms are already balanced.

Balance the oxygen atoms by adding water (H2O) molecules to the side that lacks oxygen. Since there are four oxygen atoms on the left side (MnO4-) and only two on the right side (MnO2), we need to add two water molecules to the right side:

MnO4- → MnO2 + 2H2O

Next, balance the hydrogen atoms by adding hydrogen ions (H+) to the side that lacks hydrogen. In this case, the left side (MnO4-) already has sufficient hydrogen atoms, so no hydrogen ions need to be added.

Balance the charges by adding electrons (e-) to the side that has a higher charge. MnO4- has a charge of -1, while MnO2 has no charge. Since the left side has a higher charge, we need to add electrons to the right side:

MnO4- + 4e- → MnO2 + 2H2O

Now the half-equation is balanced in alkaline medium. The Mn atoms, oxygen atoms, hydrogen atoms, and charges are all balanced. The addition of water and hydrogen ions helps balance the oxygen and hydrogen atoms, while the addition of electrons balances the charges.

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Explanation:

make me brainy least pkz

Explanation:

The rate of forward reaction is equal to the rate of backward reaction, and the overall reaction rate is zero .

But at molecular level, some part of the reactant is getting converted to the product and the same amount of product is getting converted to the reactant, therefore concentration of the both does not change but the condition is not totally static.

So, we call it a dynamic equilibrium.

Answer:

its sodium hydroxide

Explanation:

Answer:

A heterotroph is an organism that eats other plants or animals for energy and nutrients. The term stems from the Greek words hetero for “other” and trophe for “nourishment.”

Answer:

A.

............

Explanation:

Ductility

The thing that the curves tell us about the distribution of dark matter in these galaxies is option B: Most of the dark matter is in the galaxies’ outskirts.

Beyond the visible borders of galaxies, the velocity of stars remains relatively constant, suggesting that there must be more matter present than what we can see as stars and gas.

When the impact of DE became noticeable, the rotation curves are shown to dip at a specific distance. r. These flat, v = constant, rotation curve data suggest that the amount of dark matter is increasing linearly with r up to great distances from the spiral galaxies' centers.

From the graph you can see they all pointing or going one direction, hence we can deduce that it is option B.

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Answer:

In order from lowest to highest:

Methane < Ethane < Chloroethene < Methanol

i.e: CH4 < CH3CH3 < CH3CH2OH < CH3CH2Cl

Explanation:

Compounds with stronger molecular fore have higher boiling points, thus making the molecules more difficult to pull apart. The presence of chains also increases the molecular dispersion. The dipole force of ethanol makes it have a very high boiling point.

I'm positive this explanation would suffice. Best of luck.

The order of increasing boiling points of the substances listed is; CH4 < CH3CH3 < CH3CH2Cl < CH3CH2OH.

Intermolecular interactions occur between molecules. The boiling point and melting points of substances depends on the nature and magnitude of intermolecular interaction between the molecules of the substance.

The order of increasing boiling points of the substances listed is as follows; CH4 < CH3CH3 < CH3CH2Cl < CH3CH2OH. CH3CH2OH has the highest boiling point due to intermolecular hydrogen bonds in the molecule. Though CH4 and CH3CH3 are both alkanes, CH3CH3 has a higher molecular mass and consequently greater dispersion forces and a higher boiling point.

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The molarity of the solution prepared by dissolving 0.355 moles of NH₃ in enough water to make 3.84 L of solution is 0.092 M

First, we shall list out the given parameters from the question. This is given below:

Molarity of a solution is defined as mole per unit volume i.e

Molarity of solution = mole / volume

Inputting the various parameters, we have:

Molarity of solution = 0.355 / 3.84

Molarity of solution = 0.092 M

Thus, from the above calculation, it is evident that the molarity of the solution is 0.092 M

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Since she suspects that the substance is cocsine, the thing that she should do next is option 1-Perform a confirmatory test.

The way that Drug evidence is collected is that from any crime scene, evidence is obtained, photographed, packaged, documented as well as been sent for analysis and then the forensic scientist will carry out the Analysis.

Since the evidence has been sent to Roshni, all she has to do is to carry out the confirmatory test to see if the drug is what she suspected.

Therefore, Since she suspects that the substance is cocsine, the thing that she should do next is option 1-Perform a confirmatory test.

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Answer:

1) As you move down a group, first ionization energy decreases. WHY? Electrons are further from the nucleus and thus easier to remove the outermost one. 2) As you move across a period, first ionization energy increases.

so i think it is b

Explanation:

Answer:

15

Explanation:

Answer:

D -35 West

if this is correct plz mark me brainliest because this is my first question

Hope this answer helps you a lot ✅✅