The gradual temperature change from one season to the next is due to what? view attachment

160 grams of I-131 were in the original sample if the half-life is 8 days.

In a chemical reaction, the time taken for the concentration of that substance to become half of its initial value is called half-life. This term is used in nuclear physics to describe how quickly unstable atoms undergo radioactive decay .

The amount left N after n half lives of a radioactive element with original amount N₀ is given as:

N= N₀ (1/2)ⁿ

Given, half life of Iodine-131 is 8 days

n= 40/8= 5

5= N₀ (1/2)⁵

N= 32 * 5

= 160 grams

Hence, the original amount amount of  I-131 will be 160 grams.

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Answer:

Gas

Explanation:

Legend primordial element element by radioactive decay Atomic number color: red=gas

Answer:

Mass = 0.008 g

Explanation:

Given data:

Volume of H₂ = 107 mL

Pressure = 104.8 KPa

Temperature = 30°C

Mass of H₂ present = ?

Solution:

Formula:

The given problem will be solve by using general gas equation,

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K  

T = temperature in kelvin

Now we will convert the units of temperature, pressure and volume.

Temperature  = 30+273 = 303 K

Volume of H₂ = 107 mL (107/1000= 0.107 L)

Pressure = 104.8 KPa (104.8/101 = 1.04 atm)

by putting values,

1.04 atm ×0.107 L = n× 0.0821 atm.L/ mol.K  × 303 K

0.11 atm.L  = n×24.87 atm.L/ mol

n =  0.11 atm.L / 24.87 atm.L/ mol

n = 0.004

Mass of H₂:

Mass = number of moles × molar mass

Mass =   0.004    mol × 2 g/mol

Mass = 0.008 g

Answer:

The element is Sulfur.

Explanation:

Answer:

try hypocenter for the blank spot... hope this helps

Explanation:

Answer:the answer is d

Explanation:because the graph shows that that the average temperature is 53 so it only makes sense that the answer is (D)

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\ [/tex]

From the question we have

[tex]volume = \frac{12.5}{2.5} \\ [/tex]

We have the final answer as

Hope this helps you

Answer: this ones old do you still need help on this one?

Explanation:

Answer:

It becomes negatively charged

Proton is positive, electron is negative and neutron is neutral

Explanation:

Answer:

If an atom gains one electron, it will have a negative one charge, or -1.

Electrons = Negative

Protons = Positive

Answer:Compound: A substance that is made up of more than one type of atom bonded together. Mixture: A combination of two or more elements or compounds that have not reacted to bond together; each part in the mixture retains its own properties. Compound are substances which can be formed by chemically combining two or more elements. Mixtures are substances that are formed by physically mixing two or more substances. Compounds can be of three types, which are: covalent compounds, metallic compounds and ionic compounds.

Answer:

D

Explanation:

so3 +h2o =h2so4

i just searched up google i have no explanation

Answer:

¹⁶⁸₇₉Au

Explanation:

The symbol of the atom is given as;

          ¹⁷²₈₁Tl

If undergoes a nuclear reaction and it ejects an alpha particle;

 An alpha particle is the same as an helium atom

      ¹⁷²₈₁Tl  →  ₂⁴H   +     ₐᵇK

K is the hypothetical symbol of the new atom

b is the new mass number

a is the new atomic number;

 Conserving mass number;

        172  = 4 + b

        b  = 172  - 4  = 168

Conserving atomic number;

        81  = 2 + a

        81 - 2  = a

         a  = 79

The new compound is gold with a symbol of;

       ¹⁶⁸₇₉Au

Answer:

Malachite

Explanation:

Malachite is the only listed compound that must contain copper and oxygen.

Copper and oxygen are both elements found on the periodic table. They have the following symbols;

         Copper  = Cu

         Oxygen  = O

From the given choices, only option 1 has the symbol Cu and O.

So only malachite contains both copper and oxygen.

Answer:

chloroplast

Explanation:

i took the test

Answer:

Every single tonne of recycled plastic cuts carbon emissions by 1.6t and preserves 2t of crude oil. And each tonne that is recycled is not just one tonne less which the industry has to buy as crude oil on the global market – it is also one tonne less of waste plastic in our seas and oceans.

Answer:

The chemical mixture of table salt is NaCl.

Answer: 57 neutrons

Explanation: Ruthenium has an atomic number of 44, meaning it has 44 electrons, 44 protons, and 57 neutrons.

Answer:

57 neutrons

Explanation:

Ruthenium has atomic number of 44, that is, it contains 44 electrons distributed in atomic orbitals and its nucleus has 44 protons and 57 neutrons (Figure 1). Electron distribution in atomic or molecular orbitals is called electron configuration which for Ru and the other group 8 chemical elements is shown in Table 1.

Chlorine contains a total of 17 electrons which are filled in different orbitals of which 7 electrons are located in the outermost energy level or orbital.

In an atom, the electrons are surrounding the nucleus through fixed paths or energy levels called orbitals.  Electrons are filled in the increasing order of energy level. Thus lower energy levels are filled first.

The last electrons are filled in the outermost energy levels and are called valence electrons.  Each shell have a definite capacity for electrons.

Cl is 17the element in periodic table and has 17 electrons of which 7 electrons are located in the outermost shell. Hence, option A is correct.

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Answer:

true

Explanation:

Answer:

3) Ionic

Explanation:

The solid formed when a bond occurs between magnesium and oxygen is an ionic bond. This bond type occurs between a metal and non-metal.

Answer: She could have put a steel spoon into the vessel. The correct option is A.

Explanation:

When a candle wax is passed through heat, it is capable of melting within 10- 15 minutes of boiling. Therefore it is not capable of looking the same after 30 mins of heating.

When sugar is put into water it dissolves. When heated it has the ability to crystallize out after water is evaporated but doesn't retain its shape.

A piece of chocolate will melt the instance it comes in contact with any form of heat.

A steel spoon is an alloy metal which is not capable of melting by boiling in water for just 30 minutes. A steel is an alloy of Iron and carbon which melts when superheated at the temperature of 1510 degrees.

Answer:

a. qm = 627.3 J

b. qw = 627.3 J

c. C₂ = 227.4 J/kg.°C

Explanation:

a.

Since, the calorimeter is completely insulated. Therefore,

Heat Lost by Metal = Heat Gained by water

qm = qw

qm = m₁C₁ΔT₁

where,

qm = heat lost by metal = ?

m₁ = mass of water = (density)(volume) = (1000 kg/m³)(100 mL)(10⁻⁶ m³/1 mL)

m₁ = 0.1 kg

C₁ = specific heat capacity of water = 4182 J/kg.°C

ΔT₁ = Change in Temperature of Water = 19.1°C - 17.6°C = 1.5°C

Therefore,

qm = (0.1 kg)(4182 J/kg.°C)(1.5°C)

qm = 627.3 J

b.

Since,

qm = qw

qw = 627.3 J

c.

qm = m₂C₂ΔT₂

where,

m₂ = mass of metal = 38.1 g = 0.0381 kg

C₂ = specific heat capacity of metal = ?

ΔT₂ = Change in Temperature of metal = 90°C - 17.6°C = 72.4°C

Therefore,

627.3 J = (0.0381 kg)(C₂)(72.4°C)

(627.3 J)/(0.0381 kg)(72.4°C) = C₂

C₂ = 227.4 J/kg.°C

Answer:

option C is correct

Explanation:

Answer:

Explanation:

fats, proteins, and carbohydrates

Answer:

hope it helps...

Explanation:

The greenhouse effect is caused by the atmospheric accumulation of gases such as carbon dioxide and methane, which contain some of the heat emitted from Earth's surface. The atmosphere allows most of the visible light from the Sun to pass through and reach Earth's surface.

Greenhouse effect is caused by the presence of greenhouse gases in the atmosphere and the trapping of energy within the lower atmosphere.

Greenhouse gases can be defined as the gases that trap heat within the Earth's atmosphere. Some examples of greenhouse gases present in the atmosphere are:

On a related note, greenhouse effect refers a terminology that is used to describe the role that greenhouse gases play in keeping the temperature of planet Earth warm.

In conclusion, greenhouse effect is typically caused by the presence of greenhouse gases in the atmosphere and the trapping of energy within the lower atmosphere.

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Answer:

A. Atom x gains an electron

Explanation:

What happens when a bond is formed between a green gaseous element and a soft metallic element?（2.0分）

A. The gas atoms gain an electron.

B. The gas atoms lose an electron.

C. The metal atoms gain an electron.

D. The two elements share a pair of electrons

Atom X gains an electron because it needs electron to become stable.

Atom Y loses electron and atom X gains an electron in order to complete its outermost shell. Atom Y belongs to metal which has one electron while on the other hand, atom Y belongs to halogens which needs one electron for the completion of its outermost shell and become stable so atom Y loses one electron and atom X gains that electron and attain the electronic configuration of noble gases so we can say that Atom X gains an electron.

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Answer:

8.15 x 10¹⁴Hz

Explanation:

Given parameters:

Energy of photon  = 5.4 x 10⁻¹⁹J

h = 6.626 x 10⁻³⁴J.s

Unknown:

Frequency of the photon = ?

Solution:

The energy of a photon is given as;

          E = hf

h is the Planck's constant

f is the frequency

     f  = [tex]\frac{E}{h}[/tex]   = [tex]\frac{5.4 x 10^{-19} }{6.626 x 10^{-34} }[/tex]   = 8.15 x 10¹⁴Hz