When energy is changed from one form to another, _____.
A. a physical change occurs
B. all of the energy can be accounted for
C. some of the energy is lost entirely
D. all of the energy is changed to a useful form
(please explain why)

This statement is TRUE.

Explanation:

Due to the high heat capacity of water, it takes much more energy to have a gram of water raised by one degree compared to one gram of land. This is why during a hot day, the ground gets hotter faster than the adjacent oceans or adjacent lakes. It also takes water to lose the same amount of energy to have its temperatures drop by one degree as compared to land. During the night, therefore, this is why adjacent water bodies remain relatively warmer than land.

Answer :

(i) The number of atoms present in 7 g of lithium are, [tex]6.07\times 10^{23}[/tex]

(ii) The number of atoms present in 7 g of lithium are, [tex]1.204\times 10^{24}[/tex]

(iii) The number of moles of [tex]F_2[/tex] is, 1 mole

The number of moles of [tex]CO_2[/tex] is, 0.5 mole

The number of moles of [tex]OH^-[/tex] is, 1 mole

Explanation :

Part (i) :

First we have to calculate the moles of lithium.

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

Molar mass of Li = 6.94 g/mole

[tex]\text{Moles of }Li=\frac{7g}{6.94g/mol}=1.008mole[/tex]

Now we have to calculate the number of atoms present.

As, 1 mole of lithium contains [tex]6.022\times 10^{23}[/tex] number of atoms

So, 1.008 mole of lithium contains [tex]1.008\times 6.022\times 10^{23}=6.07\times 10^{23}[/tex] number of atoms

Thus, the number of atoms present in 7 g of lithium are, [tex]6.07\times 10^{23}[/tex]

Part (ii) :

First we have to calculate the moles of carbon.

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

Molar mass of C = 12 g/mole

[tex]\text{Moles of }C=\frac{24g}{12g/mol}=2mole[/tex]

Now we have to calculate the number of atoms present.

As, 1 mole of carbon contains [tex]6.022\times 10^{23}[/tex] number of atoms

So, 2 mole of carbon contains [tex]2\times 6.022\times 10^{23}=1.204\times 10^{24}[/tex] number of atoms

Thus, the number of atoms present in 7 g of lithium are, [tex]1.204\times 10^{24}[/tex]

Part (iii) :

To calculate the moles of [tex]F_2[/tex] :

[tex]\text{Moles of }F_2=\frac{\text{Mass of }F_2}{\text{Molar mass of }F_2}[/tex]

Molar mass of [tex]F_2[/tex] = 38 g/mole

[tex]\text{Moles of }F_2=\frac{19g}{19g/mol}=1mole[/tex]

Thus, the number of moles of [tex]F_2[/tex] is, 1 mole

To calculate the moles of [tex]CO_2[/tex] :

[tex]\text{Moles of }CO_2=\frac{\text{Mass of }CO_2}{\text{Molar mass of }CO_2}[/tex]

Molar mass of [tex]CO_2[/tex] = 44 g/mole

[tex]\text{Moles of }CO_2=\frac{22g}{44g/mol}=0.5mole[/tex]

Thus, the number of moles of [tex]CO_2[/tex] is, 0.5 mole

To calculate the moles of [tex]OH^-[/tex] ions :

[tex]\text{Moles of }OH^-=\frac{\text{Mass of }OH^-}{\text{Molar mass of }OH^-}[/tex]

Molar mass of [tex]OH^-[/tex] = 17 g/mole

[tex]\text{Moles of }OH^-=\frac{17g}{17g/mol}=1mole[/tex]

Thus, the number of moles of [tex]OH^-[/tex] is, 1 mole

1. The number of atoms in 7 g of Li is 6.02×10²³ atoms

2. The number of atoms in 24 g of carbon is 1.204×10²⁴ atoms

3. The number of mole in 19 g of fluorine is 1 mole

4. The number of mole in 22 g of carbon dioxide is 0.5 mole

5. The number of mole in 17 g of Hydroxide ion is 1 mole

From Avogadro's hypothesis,

1 mole of Li = 6.02×10²³ atoms

But,

1 mole of Li = 7 g

Thus,

7 g of Li = 6.02×10²³ atoms

From Avogadro's hypothesis,

1 mole of C = 6.02×10²³ atoms

But,

1 mole of C = 12 g

Thus, we can say that

12 g of C = 6.02×10²³ atoms

Therefore,

24 g of C = (24 × 6.02×10²³) / 12

24 g of C = 1.204×10²⁴ atoms

Mole = mass / molar mass

Mole of fluorine = 19 / 19

Mole of fluorine = 1 mole

Mole = mass / molar mass

Mole of CO₂ = 22 / 44

Mole of CO₂ = 0.5 mole

Mole = mass / molar mass

Mole of OH¯ = 17 / 17

Mole of OH¯ = 1 mole

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Answer:

low pressure which means means stormy weather

Explanation:

welcome to brainily, and hope this helps

Answer:

Low pressure

Explanation:

When there is a L it means low pressure which means rainy weather.It usually brings lots of rain and wind.

Answer:

38.7 g

Explanation:

first you find the molar mass of Nickle(II) Perchlorate

Nickle = 58.693 g/mol

Perchlorate is Chlorine and Oxygen combined

Molar mass of chlorine is 35.453 g/mol

Oxygen = 15.999 g/mol but since it has 4 oxygen atoms combined with chlorine you have to multiply 15.999 by 4 which is 63.996 add all the masses together and that gives you 158.142. Since you have moles you multiply the moles by the molar mass which looks like this. 0.245 * 158.142 which equals 38.74479 but with sign figs it is 38.7g as your final answer. Ask me if you are confused about something.

To find the mass of 0.245 moles of nickel(II) perchlorate, first calculate its molar mass by summing the atomic masses of nickel, chlorine, and oxygen, resulting in 257.59 g/mol. Then, multiply the number of moles (0.245) by the molar mass to get 63.11 grams.

To calculate the mass, in grams, of 0.245 moles of nickel(II) perchlorate, we need to determine the molar mass of nickel(II) perchlorate. This involves adding the atomic masses of all atoms in the formula. For nickel(II) perchlorate, Ni(ClO4)2, the calculation is as follows:

Adding these together, the molar mass of Ni(ClO4)2 = 58.69 + 70.90 + 128.00 = 257.59g/mol.

Now, to find the mass of 0.245 moles of nickel(II) perchlorate:

Mass = number of moles × molar mass = 0.245 moles × 257.59 g/mol = 63.11 grams.

Therefore, 0.245 moles of nickel(II) perchlorate has a mass of 63.11 grams.

Answer:

Explanation:

Use a upper case to identify the dominant allele and lower case to identify recessive allele.

A homozygous pea plant would be YY or gg. The homozygous recessive pea pleant would be gg (YY is dominant).

A heterozygous pea plant would be Yg (or gY which is the same).

The Punnett Square for the cross between a homozygous recessive pea plant (gg) and a heterozygous pea plant (Yg) would be:

                 g        g

       Y      Yg      Yg

       g      gg      gg

Hence, the offspring will have two Yg, which would be yellow pods, and two gg which would be green pods.

That is, 50% of the offspring will have yellow pods and 50% will have green pods.

Answer:

12.89 moles

Explanation:

Before we solve the question, we have to balance the equation of the reaction first. The balanced reaction will be:

2 NO + 2 H2→ N2 + 2 H2O

There are 180.5g of N2 produced, the number of produced in moles will be: 180.5g / (28g/mol)= 6.446 moles

The coefficient of H2 is two and the coefficient of N2 is one. Mean that we need two moles of H2 for every one mole of N2 produced. The number of H2 reacted will be: 2/1 * 6.446 moles = 12.89 moles

Answer:

12.9

Explanation:

From the question given, the concentration of the hydroxide ion is given:

[OH^-] = 1.4 x 10^ -13M

pOH =?

pOH = —Log [OH^-]

pOH = —Log 1.4 x 10^ -13

pOH = 12.9

Answer:

(Fe(OH)2 + Na2SO4

Explanation:

Iron (II) hydroxide precipitate. Iron (II) hydroxide precipitate (Fe(OH)2) formed by adding few drops of a 1M solution of sodium hydroxide (NaOH) to 0.2 M solution ferrous sulfate (FeSO4). The reaction is FeSO4 + NaOH -> Fe(OH)2 + Na2SO4. This is an example of a double replacement reaction. Pure iron (II) hydroxide is white, however even trace amounts of oxygen make it greenish.

Answer:

4- A material that transfers heat energy more easily than another material will experience a greater rate of thermal energy loss than an object that does not transfer heat energy easily.

Explanation:

Thermal energy loss has to do with loss of heat energy by a body to another body or its environment. The aim of the process is usually the attainment of thermal equilibrium between the body and its environment.

On a cold day, a material that transfers thermal energy more easily will loose thermal energy faster than an object that does not transfer thermal energy. The rate of heat transfer of a body determines its rate of loss of thermal energy.

The correct statement is 4. A material that transfers heat energy more easily than another material will experience a greater rate of thermal energy loss than an object that does not transfer heat energy easily.

To understand why option 4 is correct, let's consider the principles of heat transfer. Heat energy can be transferred in three ways: conduction, convection, and radiation. A material that transfers heat energy more easily is a better conductor of heat. This means that it allows heat to move through it more readily, either from a warmer to a cooler region or vice versa.

 On a cold day, an object's thermal energy will naturally tend to flow towards the cooler surroundings because of the temperature difference. If the material of the object is a good conductor of heat (i.e., it transfers heat energy more easily), it will lose its thermal energy to the environment at a faster rate compared to a material that is a poor conductor of heat (an insulator). This is because the good conductor does not impede the flow of heat energy, allowing it to move towards the colder surroundings more quickly.

 Conversely, a material that does not transfer heat energy easily, such as an insulator, will impede the flow of heat energy. This means that less thermal energy will be lost from the object to the environment over a given period of time, thus minimizing thermal energy loss.

Let's analyze the incorrect options:

 1. This statement is incorrect because a material that transfers heat energy at any rate will experience a change in thermal energy. If it transfers heat energy to its surroundings, it will lose thermal energy, not maintain the same level of energy.

 2. This statement is the opposite of the correct principle. A material that transfers heat energy more easily will actually lose thermal energy faster, not slower.

3. This statement is incorrect because a material that transfers heat energy at any rate will not necessarily experience an increase in thermal energy. On a cold day, the material will lose heat energy to its surroundings, not gain it.

 In summary, to minimize an object's thermal energy loss on a cold day, one should use materials that do not transfer heat energy easily, as they will resist the flow of heat away from the object, thus keeping it warmer for a longer period of time.

Answer:

Density=1.25g/dm^3

Explanation:

Density=mass/volume

Mass of nitrogen gas is 2(14)=28g

Volume at STP=22.4dm^3

Density=28/22.4=1.25g/dm^3

The mass is the molar mass of N₂ (28.01 g) and the volume is 1.25 L

To calculate the density of nitrogen gas at STP using the molar volume of a gas at STP, you can follow these steps:

1. Understand the concept: Molar volume of a gas at STP (Standard Temperature and Pressure) is 22.4 L/mol.

2. Determine the molar mass of nitrogen: The molar mass of nitrogen (N2) is approximately 28.02 g/mol.

3. Use the ideal gas law: The ideal gas law states that PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is temperature.

4. Calculate the number of moles: Since the molar volume at STP is 22.4 L/mol, and the volume is equal to 22.4 liters, the number of moles of nitrogen gas is 1 mole.

5. Calculate the density: Density (ρ) is defined as mass divided by volume. Since we have one mole of nitrogen gas, which weighs 28.02 grams, we can calculate the density as follows:

Therefore , the density of nitrogen gas at STP is 1.25 g/ L

If 10 moles of C3H4 are reacted, 30 moles of CO2 will form and 40 moles of O2 will be consumed.

In the given reaction, C3H4 reacts with 4 O2 to form 3 CO2 and 2 H2O. The stoichiometry of the reaction tells us that for every 1 mole of C3H4 reacted, 3 moles of CO2 are produced. Therefore, if 10 moles of C3H4 are reacted, we can use the ratio of moles to determine the number of moles of CO2 produced, which would be (10 moles C3H4) x (3 moles CO2 / 1 mole C3H4) = 30 moles of CO2.

In the same reaction, 4 moles of O2 react for every 1 mole of C3H4. So if 10 moles of C3H4 are reacted, we can use the ratio of moles to determine the number of moles of O2 consumed, which would be (10 moles C3H4) x (4 moles O2 / 1 mole C3H4) = 40 moles of O2.

30 moles of CO₂ will be formed for 10 moles of C₃H₄ that reacted; 40 moles of O₂ will be consumed.

To determine how many moles of CO₂ will form and how many moles of O₂ will be consumed when 10 moles of C₃H₄ are reacted, we need to use the stoichiometry of the given chemical equation:

[tex]C_3H_4 +4O_2 \rightarrow 3CO_2 +2H_2O[/tex]

Step 1: Moles of CO₂ formed:

One mole of C₃H₄ creates three moles of CO₂ according to the balancing equation.

Therefore, if 10 moles of C₃H₄ are reacted, the moles of CO₂ formed can be calculated as follows:

Step 2: Moles of O₂ consumed:

The balanced equation indicates that 1 mole of C₃H₄ consumes 4 moles of O₂.

Therefore, if 10 moles of C₃H₄ are reacted, the moles of O₂ consumed can be calculated as follows:

This analysis shows that if you start with 10 moles of C₃H₄, you will produce 30 moles of CO₂ and consume 40 moles of O₂ in the reaction.

Felsic magma, with its high silica content and high gas levels, leads to the most explosive volcanic eruptions due to the build-up of pressure and difficulty for gases to escape.

The type of magma that would produce the most explosive volcanic eruption is felsic magma. This kind of magma has high viscosity due to a higher silica content of around 70% SiO2 and contains a large amount of gas, making it quite thick. These characteristics prevent gases from escaping easily, resulting in a build-up of pressure within the magma chamber. When the pressure becomes too great, the magma breaks through the surface in a catastrophic explosion, sending rock, ash, and pyroclastic debris into the atmosphere. The explosiveness of felsic eruptions can be enhanced if there is rapid melting of ice or snow on a volcano, which can lead to devastating mudflows known as lahars.

Answer:

Explanation:

The specific heat of a substance is the amount of heat required to the raise the temperature of a unit mass of substance by 1°C.

This physical quantity is usually determined in the laboratory. It is an intensive property of substances and a constant for pure samples of material.

Specific heat for the steel wire    0.82J/g°C

specific heat for the steel wire    0.47J/g°C

specific heat for the lead pellets    0.25J/g°C

Specific heat has been defined as the amount of heat required to raise the temperature of 1 gram of substance by 1 degree Celsius.

It has been a physical quantity and has been directly proportional to the motion of molecules.

The increase in mass of the substance results in the increase in the attraction force and thus the motion of the atoms has been slow down. Thus, with the increase in mass of the element, the specific heat decreases.

The specific heat of the following elements has been:

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Answer:

2.71 × 10^24 molecules

Explanation:

We are given;

Moles of CO₂ as 4.5 moles

We are required to determine the number of molecules

From the Avogadro's constant;

1 mole of a molecular compound contains 6.022 × 10^23 molecules

Therefore;

Molecules of CO₂ = Moles of CO₂ × Avogadro's constant

That is;  

               = 4.5 moles × 6.022 × 10^23 molecules/mole

               = 2.71 × 10^24 molecules

Hence, 4.5 moles of CO₂ contains 2.71 × 10^24 molecules

Avogadro's constant is a proportionality factor, which relates to the number of units in one mole of any substance. The value of Avogadro constant is 6.022 [tex]\times 10^{23}[/tex].

Given that:

Moles of CO₂ = 4.5 moles

Number of molecules = ?

Avogadros constant = 6.022 [tex]\times 10^{23}[/tex]

Molecules in the Carbon dioxide can be calculated as:

Molecules of CO₂ = Moles of carbon dioxide x Avogadro constant

Molecules of CO₂ = [tex]4.5\times 6.022[/tex] [tex]\times 10^{23}[/tex]

Molecules of CO₂ = [tex]2.71 \times 10 ^{24}[/tex] molecules

Thus, the 4.5 moles of carbon dioxide will have  [tex]2.71 \times 10 ^{24}[/tex] molecules.

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Answer:

The number of mole is 2.422 moles

Explanation:

To calculate the number of mole, we have to use the formula n = m /Mm

n - moles

m - mass

Mm - molar mass

Let's calculate the molar mass of the compound SiO2

Si - 28.0855

O - 15.999

Note: there are two atoms of oxygen in the compound

Mm of SiO2= 28.0855+ 2* 15.999

= 60.0835g/mol

Now, we calculate the number of moles

n = 145.54g/ 60.0835g/mol

= 2.422mol

Answer:

The answer is Cell

Explanation:

Answer:

The answer is cell. A cell is the smallest unit of a living thing.

Answer:

Option B. 25 kPa

Explanation:

First, let us calculate the number of mole of CO2 in the container. This is illustrated below:

Molar Mass of CO2 = 12 + (2x16) = 12 + 32 = 44g/mol

Mass of CO2 = 0.22g

Number of mole of CO2 = 0.22/44 = 0.005mol

From the question, we obtained the following data:

V = 0.5L

T = 305K

R = 0.082atm.L/K /mol

n = 0.005mol

P =?

PV = nRT

P = nRT/V

P = (0.005x0.082x305)/0.5

P = 0.2501atm

Recall:

1atm = 101325Pa

0.2501atm = 0.2501 x 101325 = 25341.4Pa = 25341.4/ 1000 = 25KPa

Reactant C should be considered as the limiting reactant in this given situation.

Since

A balanced chemical reaction is:

A + 2B + 3C → 2D + E

And, number of moles should be

A = 0.50 mole

B = 0.60 moles

C = 0.90 moles

Now here we considered A as the reactant

So,

1 mole of A reacted to form 2 moles of D

0.50 moles of A will produce  = 1 mole of D

Now considered  B as the reactant

2 moles of B reacted to form 2 moles of D

0.60 moles of B reacted to form x moles of D

x = 2 moles of D is produced.

Now considered C as the reactant:

3 moles of C reacted to form 2 moles of D

O.9 moles of C reacted to form x moles of D

= 0.60 moles of D is formed.

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Answer:

Corn stalks  

Explanation:

Biomass fuel is produced by living or once-living organisms.

The most common biomass fuels used for energy come from plants, such as corn and soy.

B is wrong. Yellowcake is a refined form of uranium ore.  

C and D are wrong. Coal and natural gas are not biomass fuels.

Answer:

Photosynthesis

Explanation:

Photosynthesis:

It is the process in which in the presence of sun light and chlorophyll by using carbon dioxide and water plants produce the oxygen and glucose.  The oxygen produced during photosynthesis is used in cellular respiration.

The sun light is converted into chemical energy in the form of sugar.

Word equation:

Carbon dioxide + water + energy →   glucose + oxygen

water is supplied through the roots, carbon dioxide collected through stomata and sun light is capture  by chloroplast.

Chemical equation:

6H₂O + 6CO₂ + energy  →   C₆H₁₂O₆ + 6O₂

it is known from balanced chemical equation that 6 moles of carbon dioxide react with the six moles of water and created one mole of glucose and six mole of oxygen.

Answer:

Mass, M is 440.883g

Explanation:

Given the following;

Moles=4.5moles

Molar mass of H3PO4=

Atomic mass of Hydrogen H=(1*3)=3

Atomic mass of Phosphorus P=30.974

Atomic mass of Oxygen O=(16*4)=64

Therefore, Molar mass is;

H3PO4=3+30.974+64=97.974g/mol

[tex]{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]

Mass M = Number of moles × Molar mass

M = 4.5 × 97.974

M = 440.883g

Answer:

cell - basic unit of structure and function of all living things

tissue - a group of cells that work together to perform a common function

organ - a group of tissues that work together to perform a common function

organ system - group of organs that work together to perform a common function

Explanation:

What you have there is the biological level of organization. It is how living things are organized from the simplest to the most complex. Each level makes up another level.

As you can see in your exercise, the basic unit of life is the cell and cells make up tissues, while tissues make up organs and so forth. There are higher levels of organizations passed organ system.

Cell - tissue - organ - organ system - organism - population - community - ecosystem - biosphere

Answer: I believe it is coal

Explanation: Coal is the most polluting fossil fuel

Answer:

coal (a)

Explanation:

The scientific notation for the value  [tex]\frac{9 \times 10^9}{4.5 \times 10^1}[/tex] is  2  [tex]\times[/tex]  10 ^8 .

Explanation:  

                            a ^x  / a^ y  =  a ^(x  −  y )

                                            = 9  ×  10 ^9  / 4.5  ×  10 ^1

                                            =  9  / 4.5  ×  10 ^(9 − 1)

                                            = 2  [tex]\times[/tex]  10 ^8

     The scientific notation for the value  [tex]\frac{9 \times 10^9}{4.5 \times 10^1}[/tex]  is 2  [tex]\times[/tex]  10 ^8 .

Answer:

      [tex]\large\boxed{\large\boxed{x=54\º}}[/tex]

Explanation:

In the figure, two secants that intersect outside a circle form an angle with measure of xº and the measures of the arcs formed are 136º and 28º.

When two secants intersect outside a circle, the measure of the angle formed is one-half the absolute difference of the measures of the intercepted arcs.

Then, you can write and solve this equation:

           [tex]x=\dfrac{1}{2}(136\º-28\º)\\\\\\x=54\º[/tex]

Answer:

i like cheese pizza the best

Explanation:

it smacks

Answer:

   ..                                ..

   ..                                 ..

Explanation:

The Lewis dot structure of N2Br4 is attached below. A Lewis dot structure is also known as a Lewis structure or electron dot structure.

It is a visual representation of the valence electrons in an atom or molecule. It uses dots to represent the valence electrons around the atomic symbol.

The Lewis dot structure is based on the octet rule, which states that atoms tend to gain, lose, or share electrons in order to achieve a stable electron configuration with eight valence electrons (except for hydrogen, which typically only requires two valence electrons).

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Answer:

The molarity is 2, 408M

Explanation:

A solution molar---> moles of solute in 1 L of solution (1000ml):

120ml solution --------0,289 mol FeCl3

1000ml solution-------x= (1000ml solutionx0,289 mol FeCl3)/120 ml solution

x=2,408mol FeCl3--> 2, 408M

Final answer:

The molarity of the FeCl3 solution is 2.41 M.

Explanation:

To calculate the molarity of 0.289 moles of FeCl3 dissolved in 120 ml of solution, we need to convert the volume of the solution to liters. 120 ml is equal to 0.120 L. Molarity is defined as the number of moles of solute divided by the volume of solution in liters. Therefore, the molarity of the FeCl3 solution is:

Molarity = moles of solute/volume of solution

Molarity = 0.289 moles FeCl3 / 0.120 L solution = 2.41 M.