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Answer:

Heat packs that contain iron and water packets: Exposing the solution to air results in the oxidation of the iron (creates rust). The oxidation of the iron is an exothermic process. Heat packs that contain supersaturated sodium acetate: These are reusable, the packs are boiled to dissolve sodium acetate.

Explanation:Thanks for asking question

Answer:

Its in the Explanation

Explanation:

Here's what I got.

Aluminium-27 is an isotope of aluminium characterized by the fact that is has a mass number equal to  

27

.

Now, an atom's mass number tells you the total number of protons and of neutrons that atom has in its nucleus. Since you're dealing with an isotope of aluminum, it follows that this atom must have the exact same number of protons in its nucleus.

The number of protons an atom has in its nucleus is given by the atomic number. A quick looks in the periodic table will show that aluminum has an atomic number equal to  

13

.

This means that any atom that is an isotope of aluminum will have  

13

protons in its nucleus.

Since you're dealing with a neutral atom, the number of electrons that surround the nucleus must be equal to the number of protons found in the nucleus.

Therefore, the aluminium-27 isotope will have  

13

electrons surrounding its nucleus.

Finally, use the known mass number to determine how many neutrons you have

mass number

=

no. of protons

+

no. of neutrons

no. of neutrons = 27 − 13 = 14

Your welcome :)

The frequency : f = 4.478 x 10¹⁴ /s

Given

wavelength = 670 nm = 670 x 10⁻⁹ m = 6.7 x 10 ⁻⁷ m

Required

The frequency

Solution

Wavelength : from the crest to the crest of the next wave or the trough to the trough

Frequency (f): number of waves in one second

Can be formulated :

 v = λ x f

f = v / λ

So the frequency is inversely proportional to the wavelength

v = 3 x 10⁸ m/s(speed of light)

Input the value :

f = 3 x 10⁸ m/s : 6.7 x 10 ⁻⁷ m

f = 4.478 x 10¹⁴ /s

Answer:

28 %

Explanation:

Mass mass N2O = 28 + 16 = 44 mass nitrogen = 2 x 14 = 28 % nitrogen Chemistry.

Answer:

A physical change.

Explanation:

Have a wonderful day!

Answer:

The children have spent 5 of there years playing and having the time of there lives and the other 5 years are spent losing and gaining brain sells!

hope this helps:)

so sorry if this is wrong!

Answer:

Plasma.

Explanation:

In science, matter can be defined as anything that has mass and occupies space. Any physical object that is found on earth is typically composed of matter. Matter are known to be made up of atoms and as a result has the property of existing in states. The three (3) classical states of matter are;

I. Solid.

II. Liquid.

III. Gas

Plasma can be defined as a state of matter in which the electrons temporarily separate from the protons and as a result, it is generally referred to as the fourth (4th) state of matter due to its superheated nature.

Answer:

I'm pretty sure its c

Explanation:

The atomic mass of hydrogen, which is 1.008 amu, is not a whole number because hydrogen has more than one isotope.

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Answer:

its increased pressure to increase solubility

Answer:

B

Explanation:

i took the quiz

Answer:

17

Explanation:

the atomic mass is away protons + neutrons, electrons are neglatable.

Answer:

Low melting point

Explanation:

Transition metals have the following properties:

Conductivity (Electrical and Thermal)

Malleability (You can hit it with a hammer to mold it)

High melting point

Answer:

Low melting point

Explanation:

Most transition metals property is high melting point.

Answer: Convection Currents

Explanation:

Due to the different   temperature occurring at the  upper and lower layers  of the mantle, it causes  heat transfer to occur. One of such heat transfer is the Convection currents which causes  warmer, less dense rock material in the core to rise through the mantle. Also, the cooler rocks in the higher mantle move slowly towards the core.The movement caused by these  Convection current in the Earth are  called plate tectonics which are responsible for earthquakes and volcanoes.

Answer: It's A

Explanation:

Answer:

A

Explanation:

Answer:

5.95 moles

Explanation:

No of moles = given mass / molar mass

No of moles = 137/23

= 5.95 moles

Answer:

B

Explanation:

Answer:

0.87atm

Explanation:

Given parameters:

Pressure of the gas  = 1.1atm

Initial temperature  = 20.6°C  = 20.6 + 273  = 293.6K

Initial volume  = 19.2L

New volume  = 24.3L

Unknown:

New pressure  = ?

Solution:

To solve this problem, we apply the Boyle's law equation:

      P1V1  = P2V2

P and V are pressure and volume

1 and 2 are the initial and new states

        1.1 x 19.2  = P2 x 24.3

             P2  = 0.87atm

Answer:

Where are all my chemistry geniuses at?

1. The pattern of electronegativities would increase as you go across a period and would decrease as you go down a group in the periodic table.

2.  There is a correlation between electronegativity and atomic radius.  As electronegativity increases, atomic radius decreases. As electronegativity decreases, atomic radius increases. This would make sense because as a atomic radius increases, them more farther away the electrons are away from the nucleus because of their many subshells  making it less electronegative. As atomic radius decreases, the electrons are more closer to the nucleus because of their few subshells making the element more electronegative.

3. There is a correlation between ionization energy and electronegativity.  As electronegativity increases, ionization energy increases as well. If it decreases, ionization energy decreases too. This makes sense because the more electronegativity the element, the more they are closer to the nucleus(making them harder to remove) and the more desperate for an electron the atom is.

Explanation:

Hope it helped!

Answer:

+ 3

Ex planation:

Al3+ indicates an ion of aluminum having a charge of + 3. I.e., since an aluminum atom normally has 13 protons and 13 electrons, this ion has 10 electrons (-10 charge) and 13 protons (+ 13 charge) giving it a charge of + 3 (-10 + 13 = +3).

hope this helps!

Answer:

Viscosity

Explanation:

Viscosity is how thick a liquid is due to internal friction.

Answer:

A,B,C

Explanation:

Answer:

It is a Physical change, have a great day :)

Explanation:

A chemical change is a permanent change. A Physical change affects only physical properties i.e. shape, size, etc. ... Some examples of physical change are freezing of water, melting of wax, boiling of water, etc. A few examples of chemical change are digestion of food, burning of coal, rusting, etc.

Answer:

0.776 ×10²³ atoms of oxygen

Explanation:

Given data:

Mass of Al₂CO₃ = 10.0 g

Number of atoms of oxygen = ?

Solution:

Number of moles of Al₂CO₃:

Number of moles = mass/molar mass

Number of moles = 10.0 g/233.99 g/mol

Number of moles = 0.043 mol

1 mole of Al₂CO₃ contain 3 mole of oxygen.

0.043 ×3 mol = 0.129 mol

Number of atoms of oxygen:

1 mole contain 6.022×10²³ atoms

0.129 mol × 6.022×10²³ atoms / 1mol

0.776 ×10²³ atoms of oxygen

Answer:

PRACTICE MULTIPLE CHOICE QUESTIONS FROM UNIT 10

1.) A cylinder is filled with 2.00 moles of nitrogen, 3.00 moles of argon, and 5.00 moles of helium. If

the gas mixture is at STP, what is the partial pressure of the argon?

(A) 152 torr (B) 228 torr (C) 380. torr (D) 760. torr

2.) Compared to the average kinetic energy of 1 mole of water at 0 oC, the average kinetic energy

of 1 mole of water at 298 K is

(A) the same, and the number of molecules is the same

(B) the same, but the number of molecules is greater

(C) greater, and the number of molecules is greater

(D) greater, but the number of molecules is the same

3.) If the pressure on a given mass of gas in a closed system is increased and the temperature

remains constant, the volume of the gas will

(A) decrease (B) increase (C) remain the same

4.) Which gas has approximately the same density as C2H6 at STP?

(A) NO (B) NH3 (C) H2S (D) SO2

5.) At a temperature of 273 K, a 400. milliliter gas sample has a pressure of 760. millimeters of

mercury. If the pressure is changed to 380. millimeters of mercury, at which temperature will

this gas sample have a volume of 551 milliliters?

(A) 100 K (B) 188 K (C) 273 K (D) 546 K

Get the answers to these questions

Back to the Unit 10 Old Tests Pag

A displacement reaction is the one wherein the atom or a set of atoms is displaced by another atom in a molecule. For instance, when iron is added to a copper sulphate solution, it displaces the copper metal.

A + BC → AC + B

The above equation exists when A is more reactive than B.

A and B have to be either:

Halogens where C indicates a cation.

Different metals wherein C indicates an anion.

[tex]\textsf{what is a displacement reactions?   }[/tex]      

[tex]\large \underbrace{ \underline{ \sf Displacement \: reaction}}[/tex]

The reaction in which more reactive element replace a less reactive element from its compound is called displacement reaction.

Ex:-

[tex]\bold{\large Zn+HCl \longrightarrow ZnCl_2+H_2}[/tex]

Geothermal energy is heat produced by the Earth itself. It is a resource that may be gathered for human use and is renewable.

The correct option is (D) Thermal energy absorbed by the Sun at the Earth's crust

Learn more about the Geothermal energy with the help of the given link:

https://brainly.com/question/1061324

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