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Answer:

it represents the heat involved in a reaction

Explanation:

just took the test

The delta H of a reaction represents the heat involved in a chemical change .

Chemical changes are defined as changes 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 change.

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

There are three types of chemical changes:

1) inorganic changes

2)organic changes

3) biochemical changes

During chemical changes atoms are rearranged and changes are accompanied by an energy change as new substances are formed.

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Answer:

0.02

Explanation:

To solve this problem we use the Boyle's law equation

P1V1 = P2V2

P1 = 76mmHg

V1 = 0.2L

P2 = 760mmHg

V2 = unknown

Substituting values into the equation;

76mmHg * 0.2L = 760mmHg * v2

15.2 = 760V2

Divide through by 760 to get v2

15.2/760 = 0.02

So the gas will occupy a volume of 0.02 at 760mmHg

Answer:

2na+o2

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Answer:

A

Explanation:

2NA + 02

These are your reactants, which are always on the left side of the chemical equation.

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Answer:

171 moles of sodium chloride

Explanation:

Number of moles = mass/molar mass

Molar mass of sodium chloride = 58.5 g/mol

mass of sodium chloride = 10 Kg or 10,000 g

Now, to obtain the number of moles of sodium chloride;

Number of moles = 10,000 g/58.5 g/mol

Number of moles = 171 moles of sodium chloride

Answer:

true

Explanation:

Answer:

true

Explanation:

because the dissolved salt is evenly distributed throughout

Answer:

The dependent variable is the bushes of potatoes while the soil is an independent variable.

Explanation:

An experiment can be defined as an investigation which typically involves the process of manipulating an independent variable (the cause) in order to be able to determine or measure the dependent variable (the effect).

This ultimately implies that, an experiment can be used by scientists to show or demonstrate how a condition causes or gives rise to another i.e cause and effect, influence, behavior, etc in a sample.

Cause and effect can be defined as the relationship between two things or events in which an occurrence one (cause) leads to the occurrence of another (effect).

In an experiment , the variable being manipulated by an experimenter is known as an independent variable while the dependent variable is the event expected to change when the independent variable is manipulated.

Hence, the dependent variable is the bushes of potatoes while the soil is an independent variable.

Answer:

planets,meteoroids and asteroids  

Explanation:

Answer:

The answer is spontaneous.

Answer:

Substances that give H + 1 ion when dissolved in water are called acids

Explanation:

Answer:

Saturated solution

Explanation:

When is no more solute can be added then it is saturated solution

Answer:

Light refracts whenever it travels at an angle into a substance with a different refractive index (optical density). This change of direction is caused by a change in speed. ... When light enters a more dense substance (higher refractive index), it 'bends' more towards the normal line.

Sodium (Na) is atomic number 11, so it has 1 valency

While Nitrate (NO₃) has valency 1

Sodium has an extra electron while nitrate needs an extra electron, sodium gives its electron to nitrate and forms a bond,

NaNO₃ (Sodium nitrate)

Happy to help :)

Answer:

three-seventh

Explanation:

The circulation of wind in the atmosphere is driven by the rotation of the earth and the incoming energy from the sun. Wind circulates in each hemisphere in three distinct cells which help transport energy and heat from the equator to the poles. The winds are driven by the energy from the sun at the surface as warm air rises and colder air sinks.

Answer: The circulation of wind in the atmosphere is driven by the rotation of the earth and the incoming energy from the sun. Wind circulates in each hemisphere in three distinct cells which help transport energy and heat from the equator to the poles.

Explanation:

Answer:

B. hot to cold

Explanation:

Energy wants to reach thermal equilibrium (which is basically just balanced temperature) so it will move from hot to cold to make the cold object warmer and the hot object cooler.

Answer: [tex]H_2SO_4[/tex] is the limiting reagent.

Explanation:

A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.  

The balanced chemical equation is:

[tex]3H_2SO_4(aq)+2Al(OH)_3(aq)\rightarrow Al_2(SO_4)_3(aq)+6H_2O(l)[/tex]

To calculate the moles :

[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]    

[tex]\text{Moles of} H_2SO_4 =\frac{30g}{98g/mol}=0.31moles[/tex]

[tex]\text{Moles of} Al(OH)_3=\frac{25g}{78g/mol}=0.32moles[/tex]  

According to stoichiometry :

3 moles of [tex]H_2SO_4[/tex] require = 2 moles of [tex]Al(OH)_3[/tex]

Thus 0.31 moles of [tex]H_2SO_4[/tex] will require=[tex]\frac{2}{3}\times 0.31=0.21moles[/tex]  of [tex]Al(OH)_3[/tex]

Thus [tex]H_2SO_4[/tex] is the limiting reagent as it limits the formation of product and [tex]Al(OH)_3[/tex] is the excess reagent.

Answer: A mole is a chemical unit to measure mass of substance.

Explanation:

A mole can be defined as 6.02214076 × 1023 of atoms, ions, molecules and others. A mole is the total amount of discrete entity within a substance present in the form of atoms, ions, and molecules. As atoms, ions, molecules are small entities within any substance so it is necessary to measure each of them and recognize them so the scientists development the concept of mole. It is the convenient unit of measurement because of the presence of greater number of molecules, atoms, and ions present in any substance.

Answer:

The mole is an SI unit used to measure the amount of any substance. One mole is exactly 6.02214076×10 23 particles.

Explanation:

The concept of the mole is important for scientists because it means that one mole of any element has exactly the same number of atoms as one mole of any other element. This information allows chemists to count atomic particles for even very complex chemistry formulas and reactions.

Answer: Acids are chemical substances which are characterized by a sour taste in an aqueous medium. They have the tendency to turn blue litmus red. On the other hand, bases are chemical substances which are characterized by a bitter taste and are slippery to the touch. Some bases are soluble in water while others are not. Acids give off H+ (Hydrogen) ions in water; bases give off OH- (Hydroxide) ions in water. Acids generally taste sour due to the sour H+ ion; bases taste bitter due to the OH- ion; but they may have other tastes depending on the other part of the molecule. Bases are usually soapy in nature.

Explanation: Acids

Aqueous solutions of acids are electrolytes, meaning that they conduct electrical current. ...

Acids have a sour taste. ...

Acids change the color of certain acid-base indicates. ...

Acids react with active metals to yield hydrogen gas. ...

Acids react with bases to produce a salt compound and water.

Acids taste sour, conduct electricity when dissolved in water, and react with metals to produce hydrogen gas. Certain indicator compounds, such as litmus, can be used to detect acids. Acids turn blue litmus paper red. The strength of acids is measured on the pH scale.

Answer:

True.

Explanation:

The composition of a mixture is varied by altering the proportions of its constituents. True. Solutions are heterogeneous since the ratio of solute to solvent does not remain the same throughout the solution.

Answer:

0.725 moles

Explanation:

Use the mole = mass/mr equation to find the moles.

Mole = 14.5/20 (Neon's Mr) = 0.725 Moles

Answer: yes

Explanation: cuz i know lol

Answer:

2, acidic, 5, acidic

Explanation:

pH = -log[H+], where [H+] is the concentration of H+.

Using the data in the table, you can calculate the pH:

-log[1e-2] = 2

-log[1e-5] = 5

To find out whether it is acidic, basic, or neutral, use a pH scale. Anything less than 7 is acidic, anything over is basic. Knowing this, both (except the middle, which you did correctly) are acidic.

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Answer:

none

Explanation:

Answer:

None of them?

Explanation:

Answer:

Li2CO3+CaCl2=CaCO3+LiCl

Answer:

It have lower mass because much of the ashes came from the burned wood. (ashes were like little parts of the wood). plus most of the fuel was turned in to fire (light and heat energy) so yeah ash is just the left over.

Explanation:

Answer:

The more organic waste present in a landfill, the more landfill gas is produced by bacterial decomposition. Some types of organic waste contain nutrients, such as sodium, potassium, calcium, and magnesium, that help bacteria thrive. When these nutrients are present, landfill

Explanation:

Answer:

H

Explanation:

Approximately 1229.80 grams of hydrogen chloride (HCl) is produced.

We must use the specified number of moles of the limiting reactant, in this case chlorine gas [tex](Cl_2)[/tex], to calculate the mass of hydrogen chloride (HCl) produced during the reaction. We can see from the balanced equation that 1 mole of [tex]Cl_2[/tex] results in the formation of 2 moles of HCl.

Given:

Volume of Cl2 gas = 48.5 L

Temperature (T) = 450 K

Pressure (P) = 1.20 atm

Moles of Cl2 = 1.58 moles

The ideal gas law equation can be used to calculate the amount of HCl produced:

PV = nRT

Where:

P = pressure

V = volume

n = moles

R = ideal gas constant

T = temperature

First, we must use the ideal gas law equation to obtain the amount of HCl in moles:

n(HCl) = (P * V) / (R * T)

Using the known values:

n(HCl) = (1.20 atm * 48.5 L) / (0.0821 L·atm/(K·mol) * 450 K)

≈ 33.73 moles

To the nearest two decimal places, the mass of HCl is equal to its molar mass times its molar mass, or 33.73 mol times 36.46 g/mol, or 1229.80 g.

Mass of HCl = moles of HCl * molar mass of HCl

= 33.73 moles * 36.46 g/mol

≈ 1229.80 grams (rounded to two decimal places)

Therefore, approximately 1229.80 grams of hydrogen chloride (HCl) is produced.

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