the element of group 1 hour reactive but those of group 18 are inert, why?​

Answer:

false tjytyjiy

Explanation:

cnruujrkyrryyrkkurk

Answer:

There are 24*60 minutes in a day (ignoring the imperfections of the natural world, the Earth and Sun). So there are 24*60 valid 24 hour times (excluding seconds) on a digital clock.

A measure of time representing the interval between consecutive passages of the Sun across the meridian, averaged over one year. 1 day = 24 hr (86,400 sec) and 60 minutes.

hope it helps ya mate! :-P

Explanation:

2Fe (s) + 3Cl2 (g) = 2FeCl3 (s)

Answer:

the answer is 47.9 and ik because I just had that question

The empirical formula of the compound is O₄Pb₃.

An Empirical system is the chemical system of a compound that offers the proportions of the elements gifted within the compound however not the real numbers or arrangement of atoms. This would be the lowest complete variety ratio of the elements within the compound.

Amount of lead (Pb) = 90.6%

⇒and amount of oxygen = 9.4%

taking the whole number ratio

o = 4

Pb = 3

∴ ⇒O: Pb=4:3

O4Pb3 answer.

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Answer:

27.79 g to the nearest hundredth.

Explanation:

2Na + Cl2 ---> 2NaCl

Using the molar masses , the theoretical yield is:

46 g of Na yields  46 + 35.5*2 g NaCl

46 g ---> 117 g NaCl  so

11.5 g ----> 117 * 11.5 / 46 g NaCl

But, as the yield is 90%

the actual yield is 0.95 * 117 * 11.5 / 46

= 27.79 g.

Answer:

[tex]\boxed {\boxed {\sf A. \ 186.94 \ L}}[/tex]

Explanation:

We are asked to find the original volume of a gas given a change in temperature. Since pressure remains constant, we are only concerned with volume and temperature, so we use Charles's Law. This states the volume of a gas is directly proportional to the temperature. The formula for this law is:

[tex]\frac {V_1}{T_1}= \frac{V_2}{T_2}[/tex]

The gas begins with a temperature of 450 Kelvin, but the volume is unknown.

[tex]\frac {V_1}{450 \ K }= \frac{V_2}{T_2}[/tex]

The gas is cooled to 248.9 Kelvin and the gas occupies a volume of 103.4 liters.

[tex]\frac {V_1}{450 \ K }= \frac{103.4 \ L}{248.9 \ K}[/tex]

Since we are solving for the original volume, we must isolate the variable V₁. It is being divided by 450 Kelvin. The inverse operation of division is multiplication, so we multiply both sides of the equation by 450 K.

[tex]450 \ K \frac {V_1}{450 \ K }= \frac{103.4 \ L}{248.9 \ K}* 450 \ K[/tex]

[tex]V_1= \frac{103.4 \ L}{248.9 \ K}* 450 \ K[/tex]

The units of Kelvin cancel.

[tex]V_1= \frac{103.4 \ L}{248.9 }* 450[/tex]

[tex]V_1= 0.4154278827 \ L *450[/tex]

[tex]V_1= 186.9425472 \ L[/tex]

Round to the nearest hundredth. The 2 in the thousandths place tells us to leave the 4 in the hundredth place.

[tex]V_1 \approx 186.94 \ L[/tex]

The original volume is approximately 186.94 liters and Choice A is correct.

Answer:

neutrons should be added with the protons

The question requires a good knowledge of the meaning of Tyndall effect or scattering of light by false solutions in chemistry

The student observed a beam of visible light through mixture A because A exhibits Tyndall effect

Tincture of Iodine does not show Tyndall effect because its solution consists of particles less than 1 nanometer in solution.

A solution may be classified as a true solution or a false solution. A true solution consists of particles which are less than 1 nanometer in solution. A true solution does not scatter visible light.

A false solution, on the other hand consists of particles larger than 1 nanometer and does scatter visible light.

Starch in water is an example of a false solution or colloid hence it exhibits Tyndall effect. The scattering of visible light by a solution is known as Tyndall effect.

Tincture of iodine and sodium chloride in water are all true solutions hence they do not scatter visible light.

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Answer:

A Calorimeter is a device used to measure the amount of heat involved in a chemical or physical process.

Explanation:

Ex- when an exothermic reaction ( accompanied by or requiring absorption of heat)occurs in solution in a calorimeter, the heat produced by the reaction is absorbed by the solution increasing its temperature.

   - When an endothermic reaction (Heat evolving reaction) occurs, the heat required is absorbed from the thermal energy of the solution, decreasing its temperature.

A burning piece of coal which is releasing heat due to its combustion and is transferred to water.

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Answer:

from the spaces left between chains when the polymer is

formed.

Explanation:

Polyethylene polymer may be of high or low density. Whether the polymer is of high or low density depends on the arrangement of the polymer chains.

If the polymer chains are close together such that the resultant polymer is crystalline with chains packed closely, we have high density polyethylene.

On the other hand if the chains are not close together and there are spaces left between chains when the polymer is formed, then we have low density polyethylene.

Hence, low density polyethylene gets its name from the spaces left between chains when the polymer is formed.

Answer: it gets its name (from the process by which it's polymerized). Therefore the correct option is A.

Explanation:

Polyethylene is a type of plastic which is made by the polymerization of its monomers (ethene). The most common monomers are derived from petrochemicals. The monomers simply join together to form the polymers which has the same empirical formula as the monomer, but is of a higher molecular mass.

There are two main types of polyethylene, these include:

--> Low density polyethylene: when ethene is subject to a high temperature of about 250°C and pressure above 1500atm, together with traces of oxygen ( as an initiator), it polymerizes to polyethylene. The polyethylene obtained by the above method is called a low density polyethylene. It has the most long- and short-chain branching of any form of polyethylene, resulting in its lower density. Therefore its name is gotten from the process by which it's polymerized

--> High density polyethylene: this is prepared at a lower temperature and pressure by using catalysts.

Answer:

the reactants are carbon dioxide ,iron, oxygen

Answer:

d. 46.5 g

Explanation:

First, you need to start with a properly balanced equation:

N₂H₄(l) + 3O₂(g) -> 2NO₂(g) + 2H₂O(l)

Then, find the moles of water produced:

2H = 2.01568 amu

O = 15.999 amu

________________

18.01468 amu

52.4 g ÷ 18.01468 amu = 2.9087 moles

The mole ratio in our balanced formula between N₂H₄ : H₂O is 1 : 2, so divide moles of H₂O by 2 to get moles of N₂H₄

2.9087 moles ÷ 2 = 1.45435 moles of N₂H₄

Then, calculate the atomic mass of N₂H₄:

2N = 28.0134 amu

4H = 4.03136 amu

________________

32.04476 amu

Finally, calculate the mass in grams of N₂H₄:

1.45435 moles • 32.04476 amu = 46.604 g

here's the answer to your question

The relative mass of the magnesium oxide (MgO) is equal to 40 g. The percentage by mass of magnesium in MgO is 60 %.

The mass percentage of any element in a particular compound can be calculated from the number of parts by mass of the element in 100 parts by mass of a given compound.

Calculate the molar mass of the given compound by adding the atomic masses of the present elements. Then, the percentage of each element can be determined by dividing the total mass of the element by the molar mass of the compound multiplied by 100.

Given, the molecular formula of magnesium oxide is MgO. The atomic mass of Mg and O is 24 g and 16 g respectively.

The relative formula mass of the MgO = 40 g/mol

The mass percentage of the Mg = (24/40) × 100 = 60 %

Therefore, the mass percentage of the Mg in MgO is equal to 60 %.

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Answer:

The correct answer is - not very effective; forewarning tends to reduce the effectiveness of an attitude change

Explanation:

The strategy of forewarning or warning before attempting any change in the psychology of an individual is found to be less effective. The subject sees a  forewarning seen as a warning that a person is going to attempt to make changes in the attitude of a person about a particular thing or situation.

As a result, the person is ready to defenses up with regard to that idea of persuasion which Builds up defenses for the situation. Therefore, the effect of persuasion is reduced on the person.

Thus, Matty's strategy is not very effective; forewarning tends to reduce the effectiveness of an attitude change

Answer: A reaction element are those elements that can take part in a chemical reaction.

Explanation:

An element is made up of atoms that has the same atomic number. It is the basic material of which all matter is composed of. These elements cannot be broken down further into smaller substances by any chemical reaction. Each element has a unique number of protons in its atom. For example,

--> a hydrogen atom has 1 proton,

--> a Helium atom has 2 protons,

--> a Lithium atom has 3 protons, and

--> a carbon atom has 6 protons.

A chemical reaction on the other hand involves rearrangement of the constituent atoms of reactants to create different substances as products. The bonds between atoms are either broken or created to form new molecules. There are different types of chemical reaction which includes:

--> Decomposition reaction

--> Neutralization reaction

--> single displacement reaction and

--> combustion reaction.

Answer:

i think it will explode

Answer:

C2H4 Ethylene

Explanation:

Hope it helps! :)

Explanation:

HI friends good morning

Which of the following statements best explains the trends in boiling points?

A. The atomic size increases down the group, and this decreases the strength of the intermolecular forces.

                                           A is incorrect

B. The total number of electrons decreases down the group, and this decreases the strength of the intermolecular forces.

                                            B is incorrect

C. The total number of electrons increases down the group, and this increases the strength of the intermolecular forces.

                                             C is correct

D. The chances of forming a permanent dipole increases down the group, and this increases the strength of the intermolecular forces.

                                              D is incorrect

The boiling point increase down a group because the total number of electrons increases down the group, and this increases the strength of the intermolecular forces. Hence option C is correct.

Boiling point of a substance is the temperature at which the substance changes from its liquid state to vapour state. Boiling point of a molecule or compounds depends on the bond type, molecular weight, temperature and pressure.

For ionic compounds, boiling point will be higher since ionic bonds are stronger than covalent compounds. There is a periodic trend for the physical properties such as boiling point for elements in periodic table.

Down a group, the number of electrons increases and the atomic size also as well as the ionic character increases down a group . These two facts leads to higher intermolecular attraction, thus more temperature have to applied to weaken the bonds.

Higher temperature to be applied means the boiling point of the substance is higher. Therefore, boiling point down a group increases because of the higher intermolecular attraction as said in option C.

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hydrated cucl2 have blue-green colour

Answer:

The reaction between zinc and HCl is given by the symbolic equation

Zn + HCl → ZnCl2 + H2.

Explanation:

Solubility is defined as a property of solutes by virtue of which they get dissolved in a favorable solvent. The solute can only be dissolved in any suitable solvent up to a limit at a given temperature. This is a characteristic of the the solute-solvent pairing.

Answer:

chlorine Will be at highest

Answer:

- 10.6° C

Explanation:

Given that,

In the aqueous sucrose solution,

Molality of the solution (m) = 5.7

Freezing point constant (K) = 1.86

To find,

The freezing point of the solution = ?

Method:

To find its freezing point, we will first find out if the solute demonstrates an electrolyte or not.

In case it is not, the van't Hoff factor i.e. ration of particles' concentration denoted by (i) would be taken as 1. So,

ΔT(change in temperature) = i * m * K              (putting the given values)

= 1 * 5.7 * 1.86

= 10.6° C

Thus, the freezing point equals to 0 - 10.6° C = -10.6° C.

Answer:

D- Release of dust during volcanic eruption

Explanation:

During major explosive eruptions huge amounts of volcanic gas, aerosol droplets, and ash are injected into the stratosphere. Injected ash falls rapidly from the stratosphere -- most of it is removed within several days to weeks -- and has little impact on climate change. But volcanic gases like sulfur dioxide can cause global cooling, while volcanic carbon dioxide, a greenhouse gas, has the potential to promote global warming.

answer:

a - decrease in the suns energy.

explanation:

although the other options do discuss climate, temperature, etc., the sun DIRECTLY influences the earth's climate and would most likely affect it on a larger scale. for example, warm and cold ocean currents would affect the temperature of the ocean and could touch bay cities or islands, but they would not dictate the overall climate of the earth :)

♡ hopefully my reply helped you come to an answer~ please keep in mind that my response is purely that... MY response! i still have lots to learn, so please correct/educate me if you have found otherwise ♡

Answer:

linear

Explanation:

Actually I consulted various sources too and that was the most sought answer,I just decided to answer you before studying it too