⚠️help pls ⚠️
80 kg of element X decays so that 2.5 kilograms remain after 40.35 days.

a.What is the half-life of element X?

b. Identify element x.

C. Write a decay equation for the process.
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Answer:

It is malleable, ductile, and an extremely good conductor of both heat and electricity. It is softer than zinc and can be polished to a bright finish. It is found in group Ib of the periodic table, together with silver and gold. Copper has low chemical reactivity.

Answer:

= 0.5 moles of water

[tex]formular \: mass \: of \: water \: = (2 \times 1) + 16 = 18 \\ 18g \: of \: water \: are \: weighed \: by \: 1 \: mole. \\ 9g \: will \: be \: weighed \: by \: \frac{9 \times 1}{18} \\ = \frac{9}{18} moles \\ = 0.5 \: moles \: of \: water[/tex]

Answer:

0.5 mole

Explanation:

m(h2o)=2×1+16=18g

n=m÷Me=9÷18=0.5mole

Answer:

As the size of a star increases, luminosity increases. If you think about it, a larger star has more surface area. That increased surface area allows more light and energy to be given off.

Answer:

a and i thinkc

Explanation:

Answer:

see explanation

Explanation:

symbiology is (oxidation rxn || reduction rxn)

=> Zn°|Zn⁺² || Cu⁺²|Cu° => Zn°(s) + Cu⁺²(aq) => Zn⁺²(aq) + Cu°(s)

Answer:

Hey mate here's your answer ⤵️

a mark or character used as a conventional representation of an object, function, or process, e.g. the letter or letters standing for a chemical element or a character in musical notation.

noun: letter, character, sign of written communication

Something used for or regarded as representing something else; a material object representing something,

or a character of some kind

Example:

Often something immaterial; emblem, token, or sign: "$"<< the dollar sign is a symbol used to show / means money

Hope this kinda helped

Oxygen can form a covalent (molecular) bond with nitrogen. Hence, option A is correct.

A covalent bond consists of the mutual sharing of one or more pairs of electrons between two atoms.

Two covalent bonds form between the two oxygen atoms because oxygen requires two shared electrons to fill its outermost shell.

Nitrogen atoms will form three covalent bonds (also called triple covalent) between two atoms of nitrogen because each nitrogen atom needs three electrons to fill its outermost shell.

Hence, option A is correct.

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Answer:

5 ohms of resistance

Explanation:

15/3=5

Explanation:

The region x of the atom shown is called the nucleus of the atom shown. The nucleus of an atom contains protons and neutrons.

The region y is the atomic orbital where electrons can be found.

The chlorophyll processes the ingredients to make

(plant food) and

Answer:

oxygen

Explanation:

Answer:

The circulatory and respiratory systems work together to circulate blood and oxygen throughout the body. Air moves in and out of the lungs through the trachea, bronchi, and bronchioles. Blood moves in and out of the lungs through the pulmonary arteries and veins that connect to the heart

Explanation:

This should help you out

Answer:

C₆H₆O₃

Explanation:

Calculation sequence:

% => grams => moles => reduce => empirical Ratio

Molecular multiple = Molecular Mass / Empirical Mass

  C: => 57.1% => 57.1 g => 57.1/12 = 4.7583

  H: =>  4.8% =>  4.8 g =>   4.8/1  = 4.8000

  O: => 38.1% => 38.1 g => 38.1/16 = 2.3813

TTL => 100%       100 g

Reduced Mole values =>

C : H : O => 4.7583/2.3813 : 4.8000/2.3813 : 2.3813/2.3813 => 2 : 2 :  1

∴ empirical formula => C₂H₂O

empirical formula weight => 2C + 2H + 1O = [2(12) + 2(1) + 1(16)] amu = 42 amu

molecular formula weight (given in problem) = 126 g/mole

The molecular formula is a whole number multiple of the empirical formula.

molecular multiple = 126 amu / 42 amu = 3

∴ molecular formula => (C₂H₂O)₃ => C₆H₆O₃

Answer:

It will become polar.

Explanation:

Look the image below. I know it's terrible, but I'll explain it:

ΔE is the electronegativity. The higher is the ΔE of a substance, the more it can attracts electrons.

Cl has more electronegativity than C and H. But it has, of course, the same amount of another Cl.

So, when we have a tetrahedral space disposition such as in the left draw, all the Cl cancels the others eletrostatic force. However, when we replace one Cl for H, then we will have a dipole moment pointing to the Cl who face the Hydrogen, as the right draw. The appearance of a resulting dipole indicates the existence of a polar compound.

Answer:

Francium (Fr), heaviest chemical element of Group 1 (Ia) in the periodic table, the alkali metal group. It exists only in short-lived radioactive forms.

There are various kind of elements that are present in periodic table. Some elements are harmful, some are radioactive, some are noble gases. Francium  belongs to alkali metals group.

Periodic table is a table in which we find elements with properties like metals, non metals, metalloids and radioactive element arranges in increasing atomic number.

Periodic table help a scientist to know what are the different types of elements are present in periodic table so that they can discover the new elements that are not being discovered yet.

Francium is a radioactive element, the electronic configuration of Francium is [ R n] 7s¹. The number of electron in outermost shell s is 1. This shows that francium belongs to group 1 of periodic table that is alkali metals.

Therefore, Francium  belongs to alkali metals group.

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Answer: this is true

The two main postulates that was given by Antoine Lavoisier are, oxygen play an important role in combustion and the other is mass of the reactant and product is conserved. Therefore, the given statement is true.

According to Law of conservation of mass, mass can neither be created nor be destroyed. Mass can only be transformed from one form to another. The law of conservation of mass was given by Antoine Lavoisier. Every reaction in nature follow the law given by Antoine Lavoisier that is mass is always conserved.

According to this law, the number and types of atoms on reactant and product side is same. The statement " no atoms are gained or lost in a chemical reaction" is very much correct.

Therefore, the given statement is true.

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Answer:

fog

Explanation:

Answer:

Fog :)

Explanation:

:) :) :) :) :) :) :) :) :) :) :) :) :)

Answer: 2.0 atm

Explanation:

PV = nRT

P- the pressure of the gas

V- the volume it occupies

n- the number of moles of gas

R- the universal gas content

T- the absolute temp. of the gas

The pressure, in atmospheres, is exerted by 0.325 mol of hydrogen gas in a 4.08 L container at 35°C is 7.03atm.

The ideal gas law relates the pressure, volume, temperature, and number of moles of a gas through the equation:

PV = nRT

where P is the pressure in atmospheres, V is the volume in liters (L), n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin (K).

T = 35°C + 273.15 = 308.15 K

Substituting the given values into the ideal gas law equation, we get:

P × 4.08 L = 0.325 mol × 0.08206 × 308.15 K

Simplifying and solving for P, we get:

P = (0.325 mol × 0.08206× 308.15 K) / 4.08 L

P = 7.03 atm

Thus, the pressure exerted by 0.325 mol of hydrogen gas in a 4.08 L container at 35°C is 7.03 atm.

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Answer:

Magma

Explanation: cuz S waves travel through solids water, soil, and air are not solids so ur answer is B; magma

Answer:

c. soil

Explanation:

this is the correct answer not the one above...

Answer:

This can be proved by the following activity: Take some Iron fillings and dip them in the Copper sulphate solution. After some time you will notice that there is a colour change in the solution which is caused due to the displacement of Copper from it solution.

Explanation:

Answer:

Mass

Explanation:

Answer:

no. of moles = measured mass of substance/ molar mass of the constituted elements

Explanation:

No. of moles of 2.0g NaCl= 2/(23+35.5) = 0.034mol

Answer:

Because the gravitational force alters

Explanation:

Photosynthesis produces glucose and molecular oxygen. The bubbles formed here, is oxygen gas and which can be measured to determine the rate of photosynthesis.

Photosynthesis is a biochemical process by which plants produce energy and oxygen gas with the aid of light. Chlorophyll in green leaves are the photoactive substance which absorbs light energy.

The overall reaction of photosynthesis is written as below:

[tex]\rm 6H_{2}O (l) +6CO_{2} (g) \rightarrow C_{6}H_{6}O_{12}(aq) +6 O_{2} (g)[/tex]

Here, six moles of water and 6 moles of carbon dioxide reacts together to form glucose and 6 moles of oxygen.

The rate of a reaction can be determined by analyzing the product formed at regular interval. Therefore, by measuring the oxygen gas released from photosynthetic reaction in the form of bubbles the rate of reaction can be studied.

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Answer:

- A new substance was formed in the chemical change while no be substance was formed in the physical change

- The chemical change involved a change in chemical composition while the physical change involved no change in chemical composition

Please find the explanation below.

Explanation:

A physical change is a change that does not alter the chemical content of the substances involved, hence, no new substances are produced while a chemical change alters the chemical composition, hence, new substances results.

In this question,

- Water is heated till it forms steam is characterized as a physical change

- Lighted splint is applied to hydrogen gas to produce water in the form of steam is characterized as a chemical change.

- The first process is a PHYSICAL CHANGE because it involved only a change of state i.e. from liquid to gas, hence, no alteration to the chemical composition of the molecule and also no new substance is produced.

- The second process is a CHEMICAL CHANGE because there was a chemical combination of hydrogen gas and the oxygen in the lighted splint to yield water molecules ( a new substance). Therefore, it involved a chemical reaction and formation of a new substance

Answer:

What What What

Explanation:

Answer:

HAPPY BIRTHDAY!

Explanation:

Here are the steps hope it helps

Answer:

Metals i guess

Explanation:

Because each element has an exactly defined line emission spectrum, scientists are able to identify them by the color of flame they produce. For example, copper produces a blue flame, lithium and strontium a red flame, calcium an orange flame, sodium a yellow flame, and barium a green flame.

Answer:

C

Explanation:

The gas equation can be written as PV = nRT, where  

T is in kelvin, so 65 + 273 = 338K

P = 2.36 atm

Mass of Iodine gas = 254 g

R = 0.0821 (gas constant)

So,

P = (2.36*254)/(0.0821*338) = 21.63 g/L

"The density of iodine gas at 2.36 atm and 65.0 °C is 21.63 g/L."

What is density?

A substance's density will be its mass per unit volume. The most common symbol for density is D.

The formula of density can be written as:

D= P×MW/RT

where, P is pressure, MW is molecular weight( MW of iodine is 254) and R is gas constant( 0.082).

Now, put the value of given data in above equation.

D= 2.36×254/0.082×338= 21.63 g/L.

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