Radiation travels in straight lines True/False

The signal that Revere waited for was D. Lights in the North Church tower..

In Henry Wadsworth Longfellow's poem "Paul Revere's Ride," Paul Revere was waiting for a signal from the North Church tower to begin his famous ride to warn the American colonists of the approach of British troops.

According to the poem, two lanterns were hung in the tower to signal that the British were coming by sea. Revere waited for the signal to start his horseback journey to spread the word and mobilize the militia.

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Answer:

Take 1ml of given compound in a dry test tube. Add a few drops of ceric ammonium nitrate reagent and shake the solution well. Observe the solution. If red precipitate appears then the presence of alcoholic group is conformed.

Explanation:

this equation is balanced

if you look at it carefully

k=1

f=1

o=2

we do not have any opposing element

Answer:

this equation is balanced

if you look at it carefully

k=1

f=1

o=2

we do not have any opposing element

Answer:Compounds are chemical substances that contain more than one element. They're created during a chemical reaction where atoms are rearranged into new compound molecules. For example, if carbon atoms react with oxygen atoms they form carbon dioxide molecules.

Explanation:

The standard enthalpy change (∆H°rxn) for the given reaction is -38.0 kJ/mol. This negative value indicates that the reaction is exothermic, meaning that it releases heat to the surroundings.

The standard enthalpies of formation (∆Hf°) for the reactants and products involved in the reaction are: ∆Hf°[NO2(g)] = +33.2 kJ/mol. ∆Hf°[H2O(l)] = -285.8 kJ/mol. ∆Hf°[HNO3(aq)] = -207.2 kJ/mol. ∆Hf°[NO(g)] = +90.4 kJ/mol. We can use these values to calculate the standard enthalpy change (∆H°) for the reaction using the following equation:

∆H°rxn = Σn∆Hf°(products) - Σm∆Hf°(reactants) where n and m are the stoichiometric coefficients of the products and reactants, respectively. Substituting the values, we get:∆H°rxn = [2 × ∆Hf°(HNO3(aq))] + [∆Hf°(NO(g))] - [3 × ∆Hf°(NO2(g))] - [1 × ∆Hf°(H2O(l))]. ∆H°rxn = [2 × (-207.2 kJ/mol)] + [90.4 kJ/mol] - [3 × (+33.2 kJ/mol)] - [1 × (-285.8 kJ/mol)]. ∆H°rxn = -414.4 kJ/mol + 90.4 kJ/mol - 99.6 kJ/mol + 285.8 kJ/mol. ∆H°rxn = -38.0 kJ/mol

Therefore, the standard enthalpy change (∆H°rxn) for the given reaction is -38.0 kJ/mol. This negative value indicates that the reaction is exothermic, meaning that it releases heat to the surroundings.

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Answer:

Explanation:

PLATO ANSWER

The amount of heat energy absorbed when 200 grams of water are heated from 20 C to 60 C is 33,440 Joules.

To find the amount of heat energy absorbed when 200 grams of water are heated from 20 C to 60 C, we can use the equation Q = mcAT.
First, we need to find the value of m, which is the mass of the water in grams. In this case, it is given as 200 grams.
Next, we need to find the value of AT, which is the change in temperature in degrees Celsius.

This can be calculated by subtracting the initial temperature from the final temperature, which gives us 60 C - 20 C = 40 C.
The specific heat capacity of water, C, is given as 4.18 Joules per gram per degree Celsius.
Now we can plug in the values into the equation:
Q = mcAT
Q = (200 g) x (4.18 J/g°C) x (40°C)
Q = 33,440 J
Therefore, the amount of heat energy absorbed when 200 grams of water are heated from 20 C to 60 C is 33,440 Joules.

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Answer:

1.8x10_24 moleclues

Explanation:

because you have to divide the numbers  and then times them together

Answer:

the correct answer is four decimal places

Answer:

19.2 g

Explanation:

Step 1: Write the balanced equation

P₂O₅(s) + 3 H₂O(l) ⇒ 2 H₃PO₄

Step 2: Calculate the moles corresponding to 5.29 g of H₂O

The molar mass of H₂O is 18.02 g/mol.

5.29 g × 1 mol/18.02 g = 0.294 mol

Step 3: Calculate the theoretical yield of phosphoric acid, in moles

The molar ratio of H₂O to H₃PO₄ is 3:2. The theoretical yield of H₃PO₄ is 2/3 × 0.294 mol = 0.196 mol

Step 4: Calculate the mass corresponding to 0.196 moles of H₃PO₄

The molar mass of H₃PO₄ is 97.99 g/mol.

0.196 mol × 97.99 g/mol = 19.2 g

These are problems related to mixing different solutions to obtain a desired concentration.

Problem 1: 200 g of 17% solution, mix 100 g of 15% solution with 100 g of 20% solution.

Problem 2: 54 g of 18% solution and 246 g of 5% solution are needed.

Problem 3: The mass percentage of the final solution is (20015 + 35020) / (200 + 350) = 18.33%

Problem 4: The mass percentage of the final solution is (30015 + 35) / (300 + 35) = 13.23%

Problem 5: The mass percentage of the final solution is (40025) / (400 + 150) = 21.74%

Mass is a fundamental physical property of matter and is defined as the amount of matter that an object contains. It is usually measured in units of grams (g) or kilograms (kg). Mass is related to but different from weight, which is the force exerted on an object by gravity. In chemistry, mass is often used to express the amount of a substance in a sample or reaction.

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The freezing point of the solvent in a solution changes as the concentration of the solute in the solution changes (but it does not depend on the identity of either the solvent or the solute(s) particles (kind, size or charge) in the solution).

Generally, pressures lower than 1 atmosphere lower the temperature at which a substance freezes, but for water, a higher pressure gives a lower freezing point. The force from a pressure change figures into the molecular forces already at play in a substance.

Answer:

Solution-a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent).

solvent- able to dissolve other substances.

solute- the minor component in a solution, dissolved in the solvent.

colloid- a homogeneous noncrystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second substance. Colloids include gels, sols, and emulsions; the particles do not settle, and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.

suspension- is a heterogeneous mixture that contains solid particles sufficiently large for sedimentation.

Explanation:

The correct valid reason of noncovalent bonds important to function of biomolecules is A).The effect of these weak interactions is cumulative. So,correct option is A.

A noncovalent bond is a kind of synthetic bond, regularly between macromolecules, that doesn't include the sharing of sets of electrons, yet rather includes more scattered varieties of electromagnetic communications. The noncovalent bond is the predominant kind of connection between supermolecules in supermolecular chemistry.[1] Noncovalent bonds are basic in keeping up with the three-layered construction of huge atoms, like proteins and nucleic acids, and are associated with numerous natural cycles where enormous particles dilemma explicitly however fleetingly to each other.

The energy delivered in the development of noncovalent securities is on the request for 1-5 kcal per mol.[2] There are four primary kinds of non-covalent securities: hydrogen holding, ionic collaborations, Van der Waals communications, and hydrophobic bonds.[2] Instances of noncovalent securities include: those limiting connections which hold the two strands DNA in the DNA twofold helix together, those which overlap polypeptides into such optional designs as the alpha helix and the beta conformity, those which empower compounds to tie to their substrate, and those which empower antibodies to tie to their antigen.

Hence,correct option is A.

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Answer:

se que la imaje es un poco confusa con la materia pero

desiaria ayudarte pero CREO que con mi TÉCNICA  es la A

Answer:

The correct answer is -

if the potential energy of reactants is less than the potential energy then it is an endothermic reaction and if the potential energy of reactants is more than the products it is an exothermic reaction.

Explanation:

The potential energy graph represents the energy change in a reaction as it progresses. In the initial part of the reaction, the energy shows are the energy of reactants that takes part in the reaction, and in the later phase, the energy has represented the energy of products of the reaction.

To find the reaction if it is endothermic or exothermic one can see if the potential energy is increased or decrease with the progress of the reaction. if the reaction is increasing in energy with the progress then it is endothermic and exothermic in less energy.

Answer: a. 6.8 moles of water

b. 41.6 moles of carbon dioxide

Explanation:

The balanced chemical equation for formation of water is:

\(2H_2+O_2\rightarrow 2H_2O\)  

According to stoichiometry :  

1 mole of \(O_2\) produces = 2 moles of \(H_2O\)

Thus 3.4 moles of \(O_2\) produce =\(\frac{2}{1}\times 3.4=6.8moles\)  of \(H_2O\)

The balanced chemical equation for combustion of butane is:

\(2C_4H_{10}+13O_2\rightarrow 8CO_2+10H_2O\)  

According to stoichiometry :  

1 mole of butane produces = 8 moles of \(CO_2\)

Thus 5.2 moles of butane produce =\(\frac{8}{1}\times 5.2=41.6moles\)  of \(CO_2\)

The mass of the asteroid is C. 1.2 x \(10^{12}\) Kg

To find the mass of the other asteroid, we can rearrange the equation for the gravitational force between two objects:

F = (G * m1 * m2) / \(r^{2}\)

where F is the force of gravity, G is the gravitational constant, m1 and m2 are the masses of the two asteroids, and r is the distance between them.

Given that the distance between the asteroids is 75000 m, the force of gravity between them is 1.14 N, and one asteroid has a mass of 8 x \(10^{7}\) kg, we can substitute these values into the equation and solve for the mass of the other asteroid (m2):

1.14 N = (6.67430 × \(10^{-11}\) N \(m^{2}\)/\(Kg^{2}\) * 8 x \(10^{7}\) kg * \(m2\)) / \((75000 m)^{2}\)

Simplifying and solving the equation, we find that the mass of the other asteroid (m2) is approximately 1.2 x \(10^{12}\) kg. Therefore, Option C is correct.

The question was incomplete. find the full content below:

Two asteroids are 75000 m apart one has a mass of 8 x \(10^{7}\) kg if the force of gravity between them is 1.14 what is the mass of the asteroid

A. 3.4 x \(10^{11}\) kg

B. 8.3 x \(10^{12}\) kg

C. 1.2 x \(10^{12}\) kg

D. 1.2 x \(10^{10}\) kg

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Answer:

If the density of the material is equal to the density of the material you have been working with it is possible that the samples are the samples

Explanation:

Density is an intensive property of the matter (Doesn't depends of its amount) that is widely used to identify a substance. Density is the ratio between the mass of the substance (In this case 25.62g) and the volume this amount occupies (21.9cm³). The density is:

25.62g / 21.9cm³ =

1.17g/cm³.

The number of the molecules is 3.13 * 10^24 molecules

We know that by the Use of the Idea that has been put forward by Avogadro, we have to look at a mole of the substances that we need to find the number of the molecules in it and it would now lead us to working out the molar mass of the compound that is in question before we apply the Avogadro's law.

Molar mass of the compound = 3.2 + 16.0

= 19.2 g/mol

Number of moles = 100 gram/19.2 g/mol

= 5.2 moles

If 1 mole would contain 6.02 * 10^23 molecules

5.2 moles would contain 5.2 moles * 6.02 * 10^23 molecules/1 mole

= 3.13 * 10^24 molecules

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Answer:

b

Explanation:

Higher temperatures tend to increase the rate of a chemical reaction because the particles move faster and therefore collide more often.

Rate of reaction tells about the speed of the reaction or at what duration of time a reaction gets completed.

When we increases the temperature of any chemical reaction, then the kinetic energy of the molecules increases, due to which they move fast in the chemical reaction. Due to this random and fast movement molecules get collide with each other rapidly and easily form the product.

Hence option (c) is correct i.e. particles move faster and therefore collide more often when temperature increases.

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There are 0.0125 moles of Al₂(SO₄)₃ present in 50.0 mL of 0.250 M Al₂(SO₄)₃.

To determine how many moles of Al₂(SO₄)₃ are present in 50.0 mL of 0.250 M Al₂(SO₄)₃, we can use the following formula:

moles = concentration x volume

where concentration is in units of moles per liter (M), and volume is in units of liters (L).

First, we need to convert the volume from milliliters (mL) to liters (L):

50.0 mL = 50.0/1000 L = 0.0500 L

Next, we can plug in the values we know:

moles = 0.250 M x 0.0500 L

moles = 0.0125 mol

Therefore, there are 0.0125 moles of Al₂(SO₄)₃ present in 50.0 mL of 0.250 M Al₂(SO₄)₃.

Moles are a unit of measurement that is usually used in chemistry to express the quantity of a substance. As many atoms, molecules, or ions are present in 12 grams of pure carbon-12, it is the volume of a substance that includes that many of them.

Avogadro's number,  6.022 x 10²³ particles per mole, is the number of particles.

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Answer

102.816 liters

Explanation

Given:

Number of moles = 4.59 moles

At STP, one mole of any gas occupies a volume of 22.4 L

This implies;

1 mole NO₃ = 22.4 L

4.59 moles NO₃ will occupy x L

So, x will be:

102.816 liters of NO3 are in 4.59 moles of NO3

Answer:

See explanation

Explanation:

An initiation step is the first step in a free radical mechanism. In this step, free radicals are generated from a stable compound. The initiation step tends to increase the concentration of radicals present in the system.  It leads to a net increase in the number of free radicals in the system.

For the chlorination of 2,2-dimethylpropane, the initiation step is;

Cl2 + hv --------->2Cl.

Note that hv is used to represent light

Answer: (B) Buoyancy

Explanation: Buoyant force is an upward force that fluids exert on any object that is placed in them. The ability of fluids to exert this force is called buoyancy

Answer:

\(\boxed {\tt B. \ Buoyancy}\)

Explanation:

Let's define each answer choice.

A. Density

B. Buoyancy

C. Magnetism

D. Solubility

The definition that matches "the ability for something to float on water" is buoyancy. Therefore, the correct answer is B. Buoyancy

The remaining percentage of the original radioactive atoms is 321100=3. 125%.

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Answer:

Anhydrous copper (II) sulphate is white because it has no water in it. When drops of water are added, copper (II) sulphate turns blue. This colour change can be used to detect the presence of water (or water vapour).

Considering the definition of pH, the pH is 6.35 and the solution is acidic.

pH is the Hydrogen Potential and it is a measure of acidity or alkalinity. pH indicates the amount of hydrogen ions present in a solution or substance.

Mathematically, pH is calculated as the negative base 10 logarithm of the activity of hydrogen ions:

pH= - log [H⁺]

The numerical scale that measures the pH of substances includes the numbers from 0 to 14. The pH value 7 corresponds to neutral substances. Acidic substances are those with a pH lower than 7, while basic substances have a pH higher than 7.

In this case, being [H⁺]=4.5×10⁻⁷ M, you can replace this value in the definition of pH:

pH= -log (4.5×10⁻⁷ M)

Solving:

pH= 6.35

Finally, the pH is lower than 7, the solution is acidic.

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Answer: 13.4

Explanation: i guessed it and got it correct on ck-12

STP is the standard pressure and temperature condition of the ideal gas. 0.13 moles of dinitrogen monoxide will be present at STP.

An ideal gas equation is a relation between the pressure, volume with moles, gas constant, and the temperature of the ideal gas. The ideal gas equation is given by,

\(\rm PV = nRT\)

Given at STP,

Pressure = 1 atm

Volume = 300 L

Moles = ?

Gas constant =8.3144598 J per mol per Kelvin

Temperature = 273 K

Substituting values in the ideal gas equation we get:

\(\begin{aligned} \rm n &= \rm \dfrac{ PV}{RT}\\\\&= \dfrac{1 \times 300}{273 \times 8.314}\\\\&=0.1321\end{aligned}\)

Therefore, 0.13 moles of dinitrogen monoxide are produced at STP.

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