The electrons present in the valence shell of an atom are responsible for the reactivity of atoms.
What is an atom?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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why does water boil at a lower temperature at higher altitudes
the atomic number is the same as the number of which subatomic particle?
what is the three-dimensional coordination number of the face-centered cubic arrangement?
The three-dimensional coordination number of the face-centered cubic arrangement has a coordination number of 12 and contains 4 atoms per unit cell.
What is coordination number ?The coordination number, also known as ligancy, of a central atom in a molecule or crystal is the sum of all the atoms, molecules, or ions that are linked to it. This value is used in crystallography and materials science. A ligand is the ion, molecule, or atom that surrounds the center ion, molecule, or atom.
The number of atoms, ions, or molecules that a central atom or ion bears in a complex or coordination compound or in a crystal as its near neighbors is known as the coordination number, also known as ligancy.
In contrast to oxidation state, which is a number assigned to an element in chemical combination and represents the number of electrons lost or gained by an atom of that element in the compound, co-ordination number is the number of co-ordination bonds with which the ligands are bound to the central ion.
Thus, the face-centered cubic arrangement has a coordination number of 12 and contains 4 atoms per unit cell.
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Which pair of elements are in the same period?Hg & PbLi & NaB & ClO & As
Answer:
Hg Pb are in one, Li and B and O are in one, and NaCl are in one, As is alone
Explanation:
Periods are horizontal
Hope this helps!
The molar mass of water (H2O) is 18. 0 g/mol. A sample of water has a mass of 18. 0 g. How many moles of water are contained in this sample? 1. 00 18. 0 36. 0 324.
1 mole of water is contained in a sample of water that has a mass of 18.0 g.
HOW TO CALCULATE NUMBER OF MOLES:
The number of moles of a substance can be calculated by dividing the mass of that substance by its molar mass.
no. of moles = mass ÷ molar mass
According to this question, a sample of water has a mass of 18.0g. The number of moles is calculated as follows:
no. of moles of H2O = 18.0g ÷ 18g/mol
no. of moles of H2O = 1mol
Therefore, 1 mole of water is contained in a sample of water that has a mass of 18.0 g.
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the expression of potential energy , i.e., P.E.=mgh , where the terms used have their usual meaning
Gravitational Potential energy:
The Gravitational potential energy of
an object at a point above the ground
is defined as the work done in raising
it from the ground to that point against
gravity.
Consider an object of mass "m" is raised
to heighth from the ground.
A force is required to do this. the
minimum force required to raise the
object is equal to the weight of the
object[mg]
The object gains energy equal to the
work done on it. Let the work done on
the object against gravity be "w"
WorkDone=W= Force x displacement
=mgxh
..W=mgh
since the workdone on the object is
equal to "mgh" an energy equal to "mgh"
units is gained by object.This is the
potential energy of object at height "h"
.. P.E=mgh
Examine the model of the different states of matter. Select ALL of the statements that accurately describe the particles in differing states. A) Gases contain less particles. B) Gases have the greatest kinetic energy. C) Energy is removed in the change from a liquid to a gas. D) Energy is added to change from a solid to a liquid state. E) In a solid, particles are so closely packed that they can only vibrate in place.
The statements which accurately describe the particles in differing states include:
Gases have the greatest kinetic energy.Energy is added to change from a solid to a liquid state. In a solid, particles are so closely packed that they can only vibrate in place.Gases have the greatest kinetic energy which explains why its particles
move very rapidly and randomly when compared to other states of matter.
Conversion from solid to liquid or liquid to gas requires more energy being
added.
The particles in solids are tightly packed with very restricted movements
which is why they are able to vibrate at a place.
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chemical reaction occurs when the chemical identity of the reactants is different from that of the products. A new substance forms with different properties from the original react
Evidence that a chemical reaction has occurred can be a color change, light formation, gas bubbles formation, precipitate formation, or temperature change,
Use the following information to answer question 1.
QUESTION 1
Instant cold packs consist of ammonium nitrate and water. When the two are mixed, the temperature changes and becomes colder. It is described using the chemical equation
NH4NO3(s) → NH4+ (aq) + NO3(aq)
LA
Is this an example of an endothermic or exothermic reaction? Why?
Answer:
Explanation:
Exothermic: the surrounds feel warmer. A wood fire stove is a good example of an exothermic reaction. You can feel the heat on your hands. It's exothermic.
Endothermic is exactly the opposite. The reaction takes place, but the heat comes from the surroundings. When you touch something that goes through an endothermic reaction, it feels much cooler.
This reaction, just by definition is endothermic.
In 1980 the Mt. St. Helens volcano erupted and impacted thousands of square miles of forest.Some areas are still undergoing secondary succession where
Answer:
Explanation:
1: Pioneer species are the first to colonize: During primary succession in lava on Maui, Hawaii, succulent plants are the pioneer species. After weathering breaks down the lava into the soil, the plants are able to take root. These plants will help to further change the soil by adding nutrients to it.
The first organisms to appear in areas of primary succession are often mosses or lichens. These organisms are known as pioneer species because they are the first species present; pioneer species must be hardy and strong, just like human pioneers.
how much percent of water should we add to sea water to change concentration from 3 to 2
Answer:
10 kg of water was added to the 20 kg of seawater to dilute it from 3% to 2%. Hope this helps!!!!!!
how many molecules of atp are produced as a result of glycolysis
Answer:
2 ATP molecules are produced
Answer:
2 ATP molecules of ATP are produced
PLEASE HELP ME I NEED HELP ASAP SO BADLY
Answer:
160.3 g S
Explanation:
a chemical reaction in which bonds are broken is usually associated with
the release of energy
which acids are found In lemon and milk
Answer:
lemon- citric acid
milk- lactic acid
Answer:
lemon=citric and malic acids.
milk=Lactic Acid
Explanation:
A teacher places a cup of coffee onto an electronic balance at the front of the science laboratory. The teacher then adds three large teaspoons of sugar to the coffee. The volume of the coffee does not appear to increase. What happens to the mass displayed on the front of the balance?
Answer:
it will be same as before
Answer:
The mass on the balance stays the same
Explanation:
.
When a magnesium is heated, it burns in air with a dazzling white flame to form a white powder .What it called?
Balanced Equation –
[tex]\purple{\bf{2Mg + O_2 = 2MgO}}[/tex]
Physical states –
Magnesium → Mg ( In Solid State) Oxygen → [tex]\sf{O_2}[/tex] ( Gaseous State) Magnesium Oxide → MgO ( In Solid State Or White powder)_______________________________________
It is magnesium Oxide MgO2
What is the mass number (A) of an atom that has an atomic number (Z=26) with 29 neutrons and 26 electrons?
Atom information–
Atomic number (Z) = 26Protons (p⁺) = 26Neutrons (n⁰) = 29Electrons (e⁻) = 26The atomic number (Z) of an atom is the number of protons (p⁺) it hasThe mass number (A) of an atom is characterized by the sum of the amount of protons (p⁺) with its neutrons (n⁰)Substituting values –
[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf A=p^{+}+n^{0}[/tex]
[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf A=26+29[/tex]
[tex]\qquad[/tex] [tex]\twoheadrightarrow\bf A=55[/tex]
____________________________________________
Michael was sitting at his desk one morning. He noticed a small spot of light on the wall
which moved with his arm. What could be causing this spot of light on the wall?
O a) light from the window being refracted
by his watch band
b) light from the window reflecting off the
face of his watch
O c) light from the window being absorbed
by the wall
d) light from his watch refracting on the
wall
Answer:
Light from the window reflecting off the face of his watch <33
The condition of acidosis can also cause ____________ because the higher H concentration diffuses to the ICF, pushing K towards the ECF.
Answer:
Hyperkalemia
Explanation:
The condition of acidosis can also cause Hyperkalemia because the higher H concentration diffuses to the ICF, pushing K towards the ECF.
Which type of reaction is
NaOH + KNO3 NaNO3 + KOH
-->>
Answer:
Explanation:
NaOH + KNO3 --> NaNO3 + KOH. combustion. CH4 + 2 O2 --> CO2 + 2 H2O. single displacement. 2 Fe + 6 NaBr --> 2 FeBr3 + 6 Na. double displacement.
noble gases are used in many situations where a safe and constant environment must be maintained. for example, helium is used to provide a protective atmosphere for making fiber optics and semiconductors. argon is used to fill incandescent and flourescent light bulbs to prevent oxygen from corroding the hot filament. why are noble gases used in these situations?
Answer:
Noble gases have a complete valence electron shell making them stable and nonreactive.
Explanation:
Minerals are _______ substances with a fixed crystal structure and a unique chemical composition. Processing ore sometimes involves _______ or grinding minerals. Prehistoric people used _______ for knives and arrowheads. The average American house contains about _______ pounds of minerals. Early _______ used rocks as simple tools as early as 2. 6 million years ago.
Minerals are solid substances with a fixed crystal structure and a unique chemical composition. Processing ore sometimes involves crushing or grinding minerals. Prehistoric people used flints for knives and arrowheads. The average American house contains about 250,000 pounds of minerals. Early Human culture used rocks as simple tools as early as 2. 6 million years ago.
What are minerals?Minerals are solid substances and are characterized by a fixed crystal structure and a unique chemical composition.
Early hominids used rocks as simple tools before the advent of modern civilization where other materials were used.
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Answer:
1. naturally occurring
2. crushing
3. flint
4. 250,000
5. hominids
a) how many moles of o2 are needed to burn 1.50 mol of c8h18?
Answer:
Moles of oxygen needed to burn given amount of octane is 16.875 moles.
Explanation:
Find the volume of hydrogen gas that reacts with 200 cm of nitrogen gas
measured at the same temperature and pressure.
N2 + 3H2(g) 2NH3(g)
Answer:
15 L
Explanation:
The important thing to remember about reactions that involve gases kept under the same conditions for pressure and temperature is that the mole ratios that exist between the gases are equivalent to volume ratios.
This can be proven using the ideal gas law equation for two gases kept at a temperature
T
and a pressure
P
.
P
⋅
V
1
=
n
1
⋅
R
⋅
T
→
the ideal gas law equation for the first gas
P
⋅
V
2
=
n
2
⋅
R
⋅
T
→
the ideal gas law equation for the second gas
Divided these two equations to get
P
⋅
V
1
P
⋅
V
2
=
n
1
⋅
R
⋅
T
n
2
⋅
R
⋅
T
This means that you have
n
1
n
2
=
V
1
V
2
→
the mole ratio is equivalent to the volume ratio
In your case, the balanced chemical equation looks like this
N
2(g]
+
3
H
2(g]
→
2
NH
3(g]
The problem tells you that this reaction takes place at constant temperature and pressure. You don't need to know the exact values, you just need to know that they are constant for all three chemical species.
You can thus say that since you have a
1
:
3
mole ratio between nitrogen gas and oxygen gas, you will also have a
1
:
3
the volume ratio between these two gases
n
N
2
n
H
2
=
V
N
2
V
H
2
=
1
3
The volume of hydrogen gas needed to react with that much nitrogen gas will thus be
5.0
L N
2
⋅
3
L H
2
1
L N
2
=
15 L H
2
how does the number of valence electrons change as you move to the right across the periodic table?
Answer:
The number of valence electrons goes up by one each time you move
which of the following substances is most soluble in water
a). table salt
b). baking soda
c). Epsom salt
d). table sugar
Answer:
Table salt
Explanation:
Is most soluble in water
Which term describes a change that occurs with no new substances being formed?
A. Energy change
B. Bond change
C. Physical change
D. Chemical change
C. physical change
Explanation:
That's the answer
the photo has the question; please help asap ! i’m giving brainliest—i also have more chemistry, honestly i’m about to post a whole bunch of questions
Answer:
The process is to divide the molecules by Avogadro's number (6.02 x 10^23) to get the moles. And since it's specified at STP (standard temperature and pressure) we know that the molar volume would be 22.4L. So we can just multiply the moles by the molar volume in order to get the volume of H2S.
(2.18 x 10^24) / (6.02 x 10^23) = 3.62 moles (rounded)
Now just multiply the moles by the molar volume of STP, 22.4.
3.62 x 22.4 = 81 Liters (rounded) of H2S
15 POINTS AND BRAINLIEST
Martin hooked up the following circuit. He noticed that the light did not turn on. How could he fix the circuit to make it work?
A. Martin needs to have one wire coming from one side of the battery to the light bulb and one wire coming from the other side to the switch. To make a closed circuit, he can use a wire to connect the switch to the light bulb.
B. Martin needs to connect one wire from the switch to the battery and one wire from the battery to the light bulb. When he does this, it will be a closed circuit that allows electricity to flow.
C. Martin needs to turn the battery around. When he does this, it will become a closed circuit allowing electricity to flow through the circuit in a loop.
D. The switch is in the open position. If Martin lifts the switch, it will close the circuit and electricity will flow from the battery to the light bulb in a loop.
Question 17(Multiple Choice Worth 2 points)
(07.01 MC)
Answer: maybe D sorry if it's wrong
Explanation:
Distance traveled over a period of time is?
Answer:
AVERAGE speed is the total distance traveled divided by the elapsed time.