Which characteristic of a star will determine how it ends

Oxidation in chemistry occurs when the atoms of an element lose electrons and the oxidation state of the element increases while reduction occurs when the atom of an element gains electrons and reduces the oxidation number.

The atom being reduced is the oxidizing agent while the atom being oxidized is the reducing agent.

Oxidation number is the hypothetical charge of an atom within a molecule. The oxidation number of an element can be calculated as follows;

2x - 2(5) = 0

2x - 10 = 0

2x = 10

x = 5

2x - 6 = 0

2x = 6

x = 3

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Answer:In (a). 1st blank will be 1

2nd blank will be 4

3rd blank will be 3

(b).1-1

2-3

3-1

4-2

(c).1-1

2-12

3-12

4-11

(d).1-2

2-3

3-2

4-4

Explanation:

The gas law that states that, at a constant temperature, pressure is inversely proportional to volume (pv = constant, deriving from the ideal gas equation pV = nRT) was developed by:

A. Robert Boyle.

Answer:

conservation of mass

If the initial pressure was 400 torrs,  the pressure when this reaction is complete​ is  1000 torrs.

The given equation is 2NOBr(g) -> 2NO(g) + Br2(g)

This is a decomposition reaction, which means that the total number of moles of gas will increase.

From the balanced chemical equation, we can see that 2 moles of gas are produced for every 2 moles of NOBr consumed. Therefore, the number of moles of gas will double when the reaction is complete.

Let x be the final pressure of the gas mixture in torrs.

Initially, the pressure of NOBr is 400 torrs, and the initial pressure of NO and Br2 is 0 torrs.

When the reaction is complete, 2 moles of gas will be present for every 1 mole of NOBr initially present. Therefore, the final pressure of the gas mixture is:

x = (2 moles of NO + 1 mole of Br2) / (2 moles of NOBr) x 400 torrs

x = (2 + 1/2) x 400 torrs

x = 1000 torrs

Therefore, the pressure of the gas mixture when the reaction is complete is 1000 torrs.

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The basic units of the human body are called cells, and they carry out specialized tasks to keep the body alive. Cells in a city might be compared to people who perform particular duties and contribute to the general efficiency of the city.

Organizational hierarchy is built up from lower levels. Consequently, molecules combine to create molecules, molecules create cells, cells create tissues, tissues create organs, organs create organ systems, and organ systems create beings. The body's next level of organisation. A tissue is made up of related cells with a common purpose. Human tissues can be divided into four categories: epithelial, muscular, nerve, and connective.

The major levels of organisation in the body, from the most basic to the most complex, are atoms, molecules, organelles, cells, tissues, organs, organ systems, and the human body.

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Weight is the force of gravity on an object. Weight depends on the strength of the gravitational field the object is in and the mass of the object. ... Mass is constant anywhere in the universe, whereas weight depends on the gravity where the object is present (Earth, the moon, Jupiter, etc.).

The reaction order and specific reaction rate constant can be determined by performing the kinetics experiment on irreversible polymerization A. Kinetic experiments can be used to investigate the rate and mechanism of chemical reactions. Chemical kinetics is the study of chemical reactions' speed and pathway.

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Answer = 0

Explanation:

The sum of the charges of atoms of elements in a neutral compound is zero

Hence the charge of iron in the compound is 0

The charge on the iron ion in the salt Fe₂O₃ is + 3 as the charge on overall compound is 0.

An ion is defined as an atom or a molecule which has a net electrical charge. There are 2 types of ions :1) cation 2) anion . The cation is the positively charged ion and anion is the negatively charged ion . As they are oppositely charged they attract each resulting in the formation of ionic bond.

Ions consisting of single atom are mono-atomic ions while which consists of two or more ions are called as poly-atomic ions . They are created by chemical interactions . They are very reactive in their gaseous state and rapidly react with oppositely charged ions resulting in neutral molecules.

The charge on the iron ion in the salt Fe₂O₃ is calculated as 2×x+3(-2)=0  thus x= +3.

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Answer:

This question is obviously true

Explanation:

I would expect

Answer:

Mass magnesium chloride produced =  71.88g

Mass of hydrogen gas produced =  1.51 g

Explanation:

Given data:

Mass of magnesium = 36.03 g

Mass of HCl = 55.10 g

Mass of hydrogen gas produced = ?

Mass of magnesium chloride produced = ?

Solution:

Chemical equation:

Mg + 2HCl     →    MgCl₂ + H₂

Number of moles of Mg:

Number of moles = mass/molar mass

Number of moles = 36.03 g/ 24.3 g/mol

Number of moles = 1.48 mol

Number of moles of HCl:

Number of moles = mass/molar mass

Number of moles = 55.10 g/ 36.5 g/mol

Number of moles = 1.51 mol

Now we will compare the moles of hydrogen and magnesium chloride with HCl and Mg.

                            Mg            :           H₂

                             1               :            1

                            1.48          :          1.48

                          HCl            :            H₂  

                            2              :             1

                           1.51            :          1/2×1.51 = 0.755

Mass of hydrogen:

Mass = number of moles × molar mass

Mass = 0.755mol × 2 g/mol

Mass = 1.51 g

                            Mg            :           MgCl₂

                             1               :            1

                            1.48          :          1.48

                          HCl            :            MgCl₂

                            2              :             1

                           1.51            :          1/2×1.51 = 0.755

Mass of magnesium chloride:

Mass = number of moles × molar mass

Mass = 0.755mol × 95.211g/mol

Mass =  71.88g

a].When sand is added to water it either hangs in the water or forms a layer at the bottom of the container. Sand therefore does not dissolve in water and is insoluble. It is easy to separate sand and water by filtering the mixture.

b]. The water filtered by kamal is not safe to drink .

If you run out of water, or cannot carry enough water with you for your entire trip, you may need to source drinking water from natural water sources.

The aquarium has 0.35 g of dissolved oxygen in it.

The quantity of matter in an object is expressed in terms of mass. It is a scalar number, and units like grams, kilograms, and pounds are used to measure it. Weight, the force of gravity acting on an object, is not the same as mass. An object's mass is a fundamental characteristic that exists regardless of where it is or the gravitational environment it is in.

Henry's law, which connects the concentration of a gas in a solution to its partial pressure, can be used to determine the mass of oxygen (O2) that would be dissolved in a 40 L aquarium:

C = kH x P

where P is the partial pressure of the gas, kH is the Henry's law constant, and C is the concentration of the gas in the solution.

To solve the concentration by rearranging the equation, we obtain:

C = (kH x P) 

Using the above values for kH and P, we obtain:

C = (1.3 10^-3 M/atm) x (0.21 atm) = 2.73 10^-4 M.

This indicates that the aquarium's dissolved oxygen concentration is 2.73 x 10^-4 M.

We can use the following equation to determine the mass of O2 dissolved in the aquarium:

Mass = concentration x volume x molar mass.

where O2 has a molar mass of 32 g/mol.

Inputting the values provided yields:

mass = (2.73 x 10^-4 M) x 40 L x 32 g/mol = 0.35 g

As a result, the aquarium has 0.35 g of dissolved oxygen in it.

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Answer:

what you need to do is,

you take the relative atomic mass of each element and multiply it by the no of atoms it has. do this for all the elements present, and add the values. that's it!

Explanation:

try to do the last one by yourself, it is easy and you will be using the molecular/formula mass mostly everywhere in chemistry.

its True

Yes, burning of wood is an example of oxidation-reduction reaction.

hope it helps

Answer:

the reactor was overheating

Complete question is;

Chemical reactivity of alkali metals increases down the group while reactivity of halogens decreases down the group. Give reasons

Answer:

Explained below

Explanation:

Alkali metals exhibit reactivity due to their electropositivity. Now, for alkalis, their electro-positivity increases down their group. Since their reactivity increases with increase in electropositivity, it means their reactivity also increases down the group.

Whereas, the reactivity of halogens occurs as a result of their electronegativity. Now, electronegativity for halogens decreases down the group. Since their reactivity decreases with decrease in electronegativity, it means that their reactivity will also decrease down the group.

The hydrogen-rich fuel cell offers advantages in terms of efficiency, environmental impact, operating time, refueling speed, weight, size, and lifespan when compared to conventional electrochemical cells like the lead-acid battery.

The hydrogen-rich fuel cell offers several advantages over conventional electrochemical cells like the lead-acid battery. Here are some of the key advantages:

1. Higher Efficiency: Hydrogen fuel cells have higher energy conversion efficiencies compared to lead-acid batteries. Fuel cells can convert chemical energy directly into electrical energy with minimal loss, while lead-acid batteries have inherent energy losses due to factors such as internal resistance and heat dissipation.

2. Clean and Environmentally Friendly: Hydrogen fuel cells produce electricity through the reaction of hydrogen and oxygen, with water being the only byproduct. They do not produce harmful emissions or contribute to air pollution, making them a cleaner and more sustainable power source compared to lead-acid batteries, which require the use of chemicals like sulfuric acid.

3. Longer Operating Time: Fuel cells have longer operating times compared to lead-acid batteries. Lead-acid batteries have a limited capacity and need to be recharged frequently, while fuel cells can continuously generate electricity as long as there is a supply of hydrogen.

4. Faster Refueling: Refueling a fuel cell is faster compared to recharging a lead-acid battery. Fuel cells can be refueled by replenishing the hydrogen supply, which can be done relatively quickly. In contrast, lead-acid batteries require a longer time to recharge, typically hours, depending on the battery's capacity and charging rate.

5. Lighter Weight and Compact Size: Hydrogen fuel cells have a higher energy density compared to lead-acid batteries, meaning they can store more energy in a smaller and lighter package. This makes fuel cells more suitable for applications where weight and space are critical, such as in portable devices or electric vehicles.

6. Longer Lifespan: Fuel cells generally have a longer lifespan compared to lead-acid batteries. Lead-acid batteries can experience degradation over time due to factors like sulfation, which can reduce their overall capacity and lifespan. Fuel cells, on the other hand, can provide consistent performance over an extended period with proper maintenance.

These advantages make fuel cells a promising technology for various applications, including transportation, stationary power generation, and portable electronics.

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Answer:

c. carnivore means to eat meat

Answer:

c. they eat meat

Explanation:

while the other options are true those don't classify spiders as carnivores

Answer:

1) sunlight

2) radiation

3) radiant Energy

4) heat

5) temperature

Explanation:

1) Solar energy is derived from the sunlight.

2) Now, solar energy gets to the Earth's atmosphere by electromagnetic radiation which warms the Earth's surface.

3) Sunlight is a form of radiant energy because the light from the sun is transmitted by radiation to the earth.

4) When sunlight reaches the earth it is converted to heat energy.

5) Due to the heat from the sun, it will increase the Temperature of objects.

Answer:

2.7 moles of solute per 1000 mL of solution.

Explanation:

Hello,

In this case, molarity is defined as the ratio of the moles of the solute to the volume of the solution in litres, thus, for a 2.7-M solution, it is clear that we have 2.7 moles of the solute in 1 L of solution, thus the option having the proper relation is 2.7 moles of solute per 1000 mL of solution as 1 L equals 1000 mL.

Best regards.

Answer:

1 mole of Fe is 55.85 g per mole

Explanation:

hope it helps

The moles of hydrogen that are needed to make 30 moles of Fe is 45 moles.

Moles is a measurement unit. It is the quantity amount of substance.

The balanced equation is

Fe2O3 + 3H2 ---> 2Fe + 3H2O

Given the moles of iron is 30

To find the moles of hydrogen is?

According to the given balanced equation, the ratio of moles of hydrogen and iron is 3 : 2

To produce 30 moles of Fe

30 x 3 / 2 = 45 moles.

Thus, the number of moles of hydrogen is 45 moles.

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Your question is incomplete. Your most probably complete question is given below:

One way to change iron are, Fe2O3, into metallic iron is to heat it together with hydrogen:

Fe2O3 + 3H2 ---> 2Fe + 3H2O

Because air puffs up the cream as it is whipped, there is a physical change even though the ingredients are still cream and air.

Physical modifications are those that affect a chemical substance's form but not its chemical content. Physical changes may normally be used to separate compounds into chemical elements or simpler compounds, but they cannot be used to separate mixtures into their component compounds.

Liquid cream is extensively combined with small air bubbles to form the foam colloid known as whipped cream. Because milk is transformed from a colloid (cream) to a solid (butter) without changing its chemical makeup, turning milk into butter is a physical transformation. This change in the body can be undone.

Thus, there is a physical change even though the ingredients are still cream and air.

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Answer:

C6H12O6

Explanation:

C6H12O6

From the equation 2PbS + 3O2 ⟶ 2Pb + 2SO3 we can produced 8.12 g of lead  if 2.54 g of PbS is burned with 1.88 g of O2.

To find the mass of lead produced, we need to find the limiting reactant (i.e. the reactant that is consumed first).

We can find the limiting reactant by calculating the number of moles of each reactant and then using the mole ratio from the balanced equation.

Number of moles of PbS = mass / molar mass = 2.54 / 239.27 = 0.0106 mol

Number of moles of O2 = mass / molar mass = 1.88 / 32 = 0.0588 mol

From the balanced equation, the mole ratio of PbS to O2 is 2:3.

Therefore, for every 2 moles of PbS, we need 3 moles of O2.

We can use this information to calculate how many moles of O2 are needed for 0.0106 moles of PbS.0.0106 mol PbS × (3 mol O2 / 2 mol PbS) = 0.0159 mol O2.

Since the actual amount of O2 we have is less than what is needed (0.0159 mol), O2 is the limiting reactant.

This means that PbS is in excess and we can calculate the mass of lead produced using the amount of O2 that reacted.

The balanced equation tells us that 3 moles of O2 produce 2 moles of lead.

Therefore,0.0588 mol O2 × (2 mol Pb / 3 mol O2) = 0.0392 mol PbFinally, we can calculate the mass of lead produced using the number of moles and the molar mass of lead.mass of Pb = number of moles × molar mass= 0.0392 mol × 207.2 g/mol= 8.12 g.

Therefore, 8.12 g of lead will be produced if 2.54 g of PbS is burned with 1.88 g of O2.

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Answer:

Follows are the solution to these question:

Explanation:

Given equation:

\(N_2+3H_2 \longrightarrow 2NH_3\)

In this equation:

\(1 N_2\) gives \(= 2NH_3\)

so,

\(3N_2\) gives=  \(2 \times 3 = 6 NH_3\)

similarly:

\(3H_2\) gives \(= 2NH_3\)

So, \(6H_2\) gives = \(\frac{2}{3}\times 6=4NH_3\)

Its limited reagent is =\(N_2\)

The amount of \(NH_3\) molecules were formed = 4.

and the amount of  \(H_2\) excess molecules are= 1