Which of the following is an example of an exothermic reaction?

A. Cooking.
B. photosynthesis
C. Gasoline burning.
D. Instant Ice packs.

4 liters of the 70% solution are required by the chemist.

8 liters of saline solution divided by 25%

Saline solution at 25% = 0.25 x 8 = 2 liters

Let there be x liters of saline solution at 70%.

Salt = 8 plus x

40% of salt is equal to 25% of saline solution plus 70% of saline solution.

2 + (70/100)x = (40/100)(8 + x)

2 + 0.7x = 0.4(8 + x)

2 + 0.7x = 3.2 + 0.4x

0.7x - 0.4x = 3.2 - 20.3

x = 1.2

x = 1.2 / 0.3

x = 4

4 liters of the 70% solution are required by the chemist.

The following equation can be used to determine the volume or concentration of a concentrated or diluted solution: M1V1 = M2V2.

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From the coefficients of the equation, we see that for every 4 moles of aluminum consumed, 3 moles of oxygen are consumed.

So, the answer is (12/4)(3) = 9 moles.

Answer:

the electrons in them can move around easily

Explanation:

Answer:

The electrons in them being able to move around easily, and them being able to carry heat from one part to another.

Elements that are in the same group have the same number of electrons in their outer shell. These outer electrons are so important in determining the chemical properties of an element that a special way to represent them has been developed. A(n) electron dot diagram uses the symbol of the element and dots to represent the electrons in the outer shell.

The elements in the same group have the same number of electrons in their outer shell because they have the same number of valence electrons. These valence electrons are responsible for the chemical properties of an element, which is why elements in the same group have similar chemical properties. The symbol of the element is used in the electron dot diagram to represent the element, and the dots are used to represent the valence electrons in the outer shell. This diagram is a useful tool for understanding the chemical behavior of an element and for predicting how it will react with other elements.

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Answer:

382.5 grams

Explanation:

Find the molar mass of NaNO₃ and then multiply the number of moles by that molar mass :)

Moles of Hg

2 moles produce 1 mol O2

1 mol produces 1/2mol O_2

0.006 mol produces

Answer:

4 mile : 253440 inches

0.004 grams : 1.814 grams

56 miles/hour : 82.133 feet per second

4.5 ml : 0.45 centilitre

34.g/ml : 74.9571691 lb/liter

30 lb: 480 ounces

The structural formula for an alkene with the molecular formula {C6H12} that reacts with {HCl} to give the indicated chloroalkane as the major product is shown below:

The reaction of alkenes with hydrochloric acid (HCl) is an example of an electrophile addition. The products formed during this type of reaction depend on the structure of the alkene. The two carbons of an alkene are sp2-hybridized, with a trigonal planar geometry, and are unsaturated. The π electrons in the alkene are much more susceptible to attack by electrophiles, resulting in the electrophilic addition of the alkene and hydrogen halide. Given that the product is a chloroalkane, we can assume that the alkene in question reacts with HCl via electrophilic addition to form a 1-chloroalkane (a chlorinated alkane). Hence the structural formula for an alkene with the molecular formula {C6H12} that reacts with {HCl} to give the indicated chloroalkane as the major product is:  The alkene used is 3-Methylpent-2-ene (2-pentene).

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Answer:

Mass=50.0g

H=670J

change in temperature=40

using. c=h÷m×change in temperature

c=670÷50×40

C=670÷2000

C=0.335jkg-1k-1

Answer: The specific heat of a substance with a mass of 50. 0g and a temperature change of 40. 0 degrees whne it absorbs 670 J of heat is 337 J/kg. K

Explanation:

Specific heat of a substance is said to be the energy required for an increase in temperature by 1°C in the unit of J/Kg. K

Formula of Specific heat:

Q = mcΔθ

Q represents the quantity of heat

m represents the mass of the substance in Kilograms = 50. 0g÷ 1000 = 0.05kg

c represents the specific heat capacity of the substance = ?

θ represents the temperature change = 40° C

Specific heat, c = Q ÷ mΔθ

                           = 670 ÷ 0.05 × 40

                           = 670 ÷ 2

                           = 335 J/ Kg. K

Therefore, the specific heat of the substance is 335 J/kg. K

When the ticket price was $15, a total of 180 people visited the art show as it denotes a point with most accuracy.

Accuracy  in terms of chemistry can be defined as to how close a measurement is to the true value.There are three types of accuracy:

1) Point accuracy-It means accuracy is present at that point of scale only.It does not give any information about the accuracy of the instrument.

2)Percentage of true value--It is the accuracy  which is determined by identifying accuracy of the instrument  and comparing it with the measured true value.

3)Percentage of scale range- It is the accuracy  which determines accuracy of the measurement.

Accuracy of percentage of scale range type as the measurements are to be made within a range where the sample has to be measured.

Accuracy in case of instruments  is neglected up  to ±0.5 percent.

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Answer: Fossil fuels may be used in the production of biofuels.

Explanation: Defeats the purpose of using biofuels over fossil fuels if one contains the other.

Answer:

D

Biofuel Disadvantages:

Labor costs are high, and storage space is limited. Excessive water use, particularly in dry areas. Increasing biomass for biofuel production raises agricultural land requirements. 

The amount of aluminum that reacted is approximately 0.069 grams.

To determine the mass of aluminum that reacted, we need to use the ideal gas law and consider the partial pressure of hydrogen gas. First, we calculate the pressure of hydrogen gas by subtracting the partial pressure of water vapor from the total pressure. The pressure of hydrogen gas is 751 mmHg - 26.8 mmHg = 724.2 mmHg.

Next, we convert the pressure of hydrogen gas from mmHg to atm by dividing by 760 mmHg/atm, giving us 0.953 atm.

Using the ideal gas law equation PV = nRT, we can calculate the number of moles of hydrogen gas. The volume of hydrogen gas is given as 37.3 mL, which we convert to liters by dividing by 1000 mL/L, giving us 0.0373 L. The temperature is given as 27°C, which we convert to Kelvin by adding 273.15, giving us 300.15 K. The ideal gas constant R is 0.0821 L∙atm/(mol∙K).

Plugging the values into the ideal gas law equation, we can solve for the number of moles of hydrogen gas: (0.953 atm) * (0.0373 L) = n * (0.0821 L∙atm/(mol∙K)) * (300.15 K).

Simplifying the equation, we find that the number of moles of hydrogen gas is approximately 0.00139 moles.

Since the balanced chemical equation between aluminum and hydrochloric acid is 2Al + 6HCl → 2AlCl₃ + 3H₂, we can conclude that 2 moles of aluminum react to produce 3 moles of hydrogen gas.

Using this ratio, we can calculate the number of moles of aluminum that reacted: (0.00139 mol H₂) * (2 mol Al / 3 mol H₂) = 0.000926 moles Al.

Finally, we can convert moles of aluminum to grams using the molar mass of aluminum (26.98 g/mol): (0.000926 mol Al) * (26.98 g/mol) ≈ 0.069 g Al.

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Answer: The balanced equation is \(AlCl_{3} + 3Cs \rightarrow 3CsCl + Al\)

Explanation:

A chemical equation which contains same number of atoms on both reactant and product side is called a balanced chemical equation.

For example, \(AlCl_{3} + Cs \rightarrow CsCl + Al\)

Here, number of atoms on reactant side are as follows.

Number of atoms on product side are as follows.

To balance this equation, multiply Cs by 3 on reactant side and multiply CsCl by 3 on product side.

Hence, now the equation will be as follows.

\(AlCl_{3} + 3Cs \rightarrow 3CsCl + Al\)

Here, number of atoms on reactant side are as follows.

Number of atoms on product side are as follows.

Thus, we can conclude that this equation is balanced.

The mass of oxygen reacted/required in this reaction is obtained as 48g.

The term stoichiometry has to do with mass- volume or mass - mole relationship which ultimately depends on the balanced reaction equation.

Now, we have the reaction; S + O2 ------>SO2

If 1 mole of sulfur dioxide contains 22.4 L

x moles of sulfur dioxide contains 33.6L

x = 1.5 moles of sulfur dioxide.

Since the reaction is 1:1, the number if moles of oxygen required/reacted is 1.5 moles.

Mass of oxygen required/reacted = 1.5 moles * 32 g/mol = 48g

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What are the relative w/v concentrations of lactic acid, citric acid, and boric acid if the mixture's specific gravity is 0.781? What are the % weight-to-volume conversions if the mixture's specific gravity is 0.781?

(Density of the solution / Water Density)

density of mixture = (specific gravity of mixed * density of waters) = (0.781 * 1) = 0.781 g/mL density = (mass/volume) specific gravity = 0.781

Lactic acid concentration in the mixture = (mass of latic acid / quantity of mixture) *100 = (4/128.04)100 = 3.12%. Volume of mixture = (mass / density) = (100 /0.781) =128.04 mL.

What level of fluoride ion should be present in drinking water?

Detailed Solution: 1 mg/l

1.50 mg per liter is the proper answer. The World Health Assembly advised that the maximum allowed level of fluoride present in drinking water for a number of nations, including Canada, China, India, Argentina, and the European Union, be 1.5 mg/l. A fluoride level of 1 mg/l is ideal for drinking water.

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The w/v levels of lactic acid, benzoyl peroxide, plus trichloroacetic acid as in combination are 1.56% if the mixture has a specific gravity of 0.781.

1 mg/l 1.50 mg per liter is the proper answer. The World Health Assembly advised that the maximum allowed level of fluoride present in drinking water for a number of nations, including Canada, China, India, Argentina, and the European Union, be 1.5 mg/l. A fluoride level of 1 mg/l is ideal for drinking water.

(Density of solution / Water Density) = Specific Gravity

density of mixture = (specific gravity of mixed * densities of water) = (0.781 * 1) = 0.781 g/mL density = (mass/volume) specific gravity = 0.781

Volume of the mixture = (Mass of Lactic Acid / Volume of the mixture) = (100 /0.781) =128.04 mL w/v Amount of Lactic in the mixture Salicylic acid concentration in the mixture is *100 = (4/128.04)100 = 3.12% w/v = (mass of Salicylic / volume of mixture). Trichloroacetic acid concentration in the combination: *100 =(5/128.04)100 = 3.9% w/v (i.e., (mass of Trichloroacetic acid / volume of mixture) *100 =(2/128.04)100 = 1.56%

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A solution at pH 1 has more hydrogen ions than a solution at pH 4. The pH of a solution refers to the hydrogen ion concentration.

The concentration of hydrogen ions and the pH of a solution are inversely proportional. This means that the higher the hydrogen ion concentration, the lower the pH, and vice versa.

A solution at pH 1 will have more hydrogen ions than a solution at pH 4.The pH of a solution is defined as the negative logarithm of the hydrogen ion concentration. The equation for calculating the pH of a solution is given as follows:

\($$pH = -\log_{10}[H^+]$$\)

In this equation, [H⁺] is the hydrogen ion concentration in moles per liter (mol/L) of solution. A change of 1 pH unit corresponds to a 10-fold change in the hydrogen ion concentration.

Therefore, if a solution has a pH of 1, it has a hydrogen ion concentration of 0.1 mol/L.

If a solution has a pH of 4, it has a hydrogen ion concentration of 0.0001 mol/L. Thus, a solution at pH 1 has more hydrogen ions than a solution at pH 4.

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Answer:

C. A one (1) is assumed when there is no coefficient

Explanation:

The following chemical equation is given in the attachment:

2H2 + O2 → 2H2O

In this reaction, Hydrogen (H2) and oxygen (O2) gases are the reactants and they combine to form H2O, which is the product. It is necessary that, in accordance to the law of conservation of matter, the same number of atoms of each elements on the reactant side equates that on the product side. When this happens, the equation is said to be BALANCED.

However, to balance an equation, COEFFICIENTS are used. In this equation above, coefficients 2 is used in front of both H2 and H2O but no coefficient is used in front of O2. This is because 1 mole of oxygen is on the reactant and product side respectively. However, one is assumed when no coefficient is written i.e. O2 means 1 mole of oxygen molecule.

Answer:

True!

Explanation:

A spectrum is simply a chart or a graph that shows the intensity of light being emitted over a range of energies. Have you ever seen a spectrum before? Probably. Nature makes beautiful ones we call rainbows. Sunlight sent through raindrops is spread out to display its various colors (the different colors are just the way our eyes perceive radiation with slightly different energies).

Hope i helped!

Answer:

you have to divide it

Explanation:

Answer:

whats the volume u can't find the density without dividing the mass by the volume

2moles of H2O are made when 6moles of HNO3 are consumed

75 mole of HNO3 produces = \(\frac{2}{6}\)× 75 ⇒ 25 moles of water

The limiting reagent is the reactant that is completely used up in a reaction and thus determines when the reaction stops.

S + 6 HNO3 --> H2SO4 + 6 NO2 + 2 H2O

6 mole of HNO3 produces \(\frac{2}{6}\) = 2 moles of H₂O

1 mole of HNO3 produces =  mole of H₂O

∴ 75 mole of HNO3 produces = \(\frac{2}{6}\) × 75 ⇒ 25 moles of water

Answer:

Compression

Explanation:

Hi! When two convergent plates collide, they should create compressive pressure, or compression.

Endothermic reactions are those in which heat is absorbed from the surroundings.

They are reactions in which heat is absorbed from the surrounding, making the reaction vessels become colder.

It is unlike exothermic reactions in which heat is released into the surrounding, making the reaction vessel to be warmer.

For endothermic reactions, the enthalpy change is always positive because heat is absorbed. It is however negative for exothermic reactions because heat is evolved.

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Answer:

B. 6CO2 + 12H2O + energy =  C6H12O6 + 6O2 + 6H2O

Explanation:

Answer:

Nuestra alimentacion debe estar basada en alimentos ricos en vitaminas, minerales como las frutas verduras, legumbres  y semillas.

Explanation:

Los alimentos ultraprocesados son altos en sodio, conservantes, y pobres en vitaminas, es por eso que deben ser evitados ya que algunos hasta se consideran hasta carcinogenos.

No se descarta los compuestos quimicos ultraprocesados ricos en grasa perjudiciales para la salud ya que fomentan la formacion de placa de ateromas.

Hydrocarbons are generally soluble in nonpolar solvents.

Hydrocarbons are generally soluble in nonpolar solvents such as benzene because they have similar molecular characteristics.

Hydrocarbons are molecules composed of carbon and hydrogen atoms that form nonpolar covalent bonds. Since these molecules have no charge, they do not readily dissolve in polar solvents such as water, which is composed of polar covalent bonds with partial positive and negative charges on its atoms.

Benzene, on the other hand, is a nonpolar solvent that is composed of carbon and hydrogen atoms arranged in a symmetrical ring structure. The electrons in benzene are shared equally between its atoms, making it nonpolar and unable to dissolve polar substances.

When hydrocarbons are added to benzene, the nonpolar nature of both substances allows them to mix and dissolve into one another. This is due to the fact that like dissolves like, meaning that polar solvents dissolve polar solutes and nonpolar solvents dissolve nonpolar solutes.

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A compound that binds to a receptor but does not activate the neuron is known as an Antagonist.

A receptor is a large protein molecule on a neuron that gets activated when a ligand binds to it such as a drug or hormone, or when electrical impulses pass through it.

An antagonist is a drug or hormone that binds to receptor, but instead of activating the receptor, it blocks or dampens the activation of the neuron. Antagonist drugs are used to interfere with the normal function or operation of a protein receptor.

Depending on the nature of the antagonist or the receptor it's bound to, the effects of antagonists may be permanent or temporary.

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Answer: A

Explanation: I hope this helps!

Answer:

A or C. Best to go with A

Explanation:

Hope it works!!

mitochondria

im not 100% sure but it makes sense