Answer:
The valence electron configuration determines the group to which an element belongs to.
Explanation:
The valence electron configuration of an atom of an element refers to the number of electrons in that atoms outermost shell.
The valence electron configuration is related to the group number of an element in that the number of electrons in the valence shell of an atom of an element determines the group to which an element belongs to. For example, all elements having one valence electron belong to group IA of the periodic table. Similarly, all elements having seven valence electrons belong to group VIIA of the periodic table.
This is because, since the reactivity of an element is related to its ability to either gain or lose a certain number of electrons in its valence shell, elements having same number of valence electrons have similar chemical properties.
How many neutrons make up one of these potassium atoms?
Answer:
20
Explanation:
Why are biopharmaceuticals in high demand?
Answer:
the market is largely driven by the growing population, increasing burden of chronic disease, and rising inclination toward targeted therapy.
Explanation:
also, the huge demand of biopharmaceutical is facilitated by an accelerating focus in research and related investment.
An orange falls off of a display at a store and rolls 5 meters in 2.5 seconds. What is the average speed of the orange?
An orange falls off of a display at a store and rolls 5 meters in 2.5 seconds the average speed of the orange will be 2 meters per second.
What is speed?Speed if the rate of change of position of an object in a given time of interval or per unit time of interval and it is the ratio of distance traveled to the time taken and the unit will be meter per second.
The average speed of the orange will be if the orange falls off of a display at a store and rolls 5 meters in 2.5 seconds,
Speed = distance / time
Substituting the value,
speed =5 meters /2.5 seconds
speed = 2 meters per second.
Therefore, the average speed of the orange will be 2 meters per second if, the orange falls off of a display at a store and rolls 5 meters in 2.5 seconds.
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What causes the
differences in physical characteristics like hair color among people?
1. diferent versions of genes
2. variations in DNA length
3. different numbers of chromosomes
4. variations in cell nucleus size
Answer:
b
Explanation:
i took the test
How many electrons are there in the only energy level of helium, a noble gas? * Two Three Six Eight
Answer:
Explanation:
Noble gases are the least reactive of all known elements. That's because with eight valence electrons, their outer energy levels are full. The only exception is helium, which has just two electrons.
Why does an ion have a charge
Help please:)
Answer:
An ion is charged because the number of electrons does not equal the amount of particles.
Explanation:
Can be positive (meaning more protons than electrons) and it can be negatively charged (meaning there are more electrons than protons).
Hope this helps!
Answer:
An ion has a charge because the number of electrons dont equal the amount of protons in the molecule or atom.
Explanation:
The negative or positive charge depend on wether the atom or molecule has more electrons(-) or protons(+).
what is the mass of a 7.91 cm cubed piece of lead having a density of 11.34 g/cm cubed
Answer:
The answer is 89.70 gExplanation:
The mass of a substance when given the density and volume can be found by using the formula
mass = Density × volumeFrom the question
density = 11.34 g/cm³
volume = 7.91 cm³
We have
mass = 11.34 × 7.91 = 89.6994
We have the final answer as
89.70 gHope this helps you
Why are small quantities of chlorofluorocarbons so harmful to the ozone layer? a. The chlorofluorocarbons act like ultraviolet radiation causing large amount of ozone to be produced. b. The chlorine from the chlorofluorocarbons reacts with free molecules of oxygen causing a stop in ozone production. c. Free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone. d. Chlorofluorocarbons absorb ultraviolet radiation, preventing the formation of ozone.
Answer:
Why are small quantities of chlorofluorocarbons so harmful to the ozone layer? Free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone.
Explanation:
The statement for small quantities of chlorofluorocarbons so harmful to the ozone layer is "Free oxygen atoms can replace the chlorine in chlorine monoxide, releasing a free atom of chlorine which can then recombine with an oxygen atom in ozone, destroying more ozone."
What is ozone layer?The ozone layer is a thin layer of air in the Earth's atmosphere that absorbs nearly all of the sun's damaging UV radiation.
What is CFCs?CFCs (chlorofluorocarbons) are harmless and nonflammable compounds made up of carbon, chlorine, and fluorine atoms.
The earth's protective ozone layer is destroyed by chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and halons, which shield the earth from damaging ultraviolet (UV-B) rays released by the sun. CFCs and HCFCs also warm the earth's lower atmosphere, causing global climate change.
When some substances are exposed to high UV radiation in the stratosphere, they emit chlorine or bromine. Ozone-depleting chemicals are compounds that contribute to ozone depletion (ODS). Chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), carbon tetrachloride, and methyl chloroform are examples of ODS that produce chlorine. Halons and methyl bromide are two ODS that emit bromine.
Because there isn't much ozone in the atmosphere, what little there is is critical for protecting the Earth's surface from excessive UV light from the Sun. It turns out that it reacts with chlorine, which means that chlorine effectively eliminates ozone.
When the chlorine in CFCs combines with ultraviolet light, it releases chlorine, which then reacts with ozone, reducing the protection humans get from ultraviolet light, allowing more CFCs to release chlorine, and so on. Multiple ozone molecules will interact with one free chlorine atom, which is free because UV light has hit the CFC molecule. As a result, the damage it can cause is likely to be significantly more than you might imagine.
Hence the correct option is c.
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The substances that get rid of carbamates and organophosphates are?
Answer: Alfracon
...............................
Unit: Scientific Measurement“One, Two, and More Step Problems” – Wksh #2
1.How many g are equal to 345.7 mg?
2.Change 0.00765 kL into mL.
3.How many seconds are there in 2.5 days?
4.How many minutes are there in 1.000 week?
5.How many seconds long is this chemistry class if it lasts 40.0 minutes?
6.A chemistry student’s height is measured at 68.5 inches. How tall is the student in cm?
7.This same chemistry student has a weight of 155 lbs. What is the student’s weight ingrams? (16oz=1lb, 1 oz = 28.34 g)
8.A homerun in a baseball game was measured at 450 feet. How many meters is this equalto?
9.Mount Everest is approximately 8,000 meters high. How many miles high is MountEverest?
10.A 5.0 km race is scheduled for this weekend. How many miles is this race?
Answer:
1. 0.3457g
2. 7650mL
3. 216000 seconds
4. 10080minutes
5. 2400 seconds
6. 173.99cm
7. 70283.2g
8. 137.16metres
9. 4.968miles
10. 3.105miles
Explanation:
1. 1000mg = 1g
345.7 mg = 345.7/1000
= 0.3457g
2. 1kL = 1000000mL
0.00765 kL = 0.00765 × 1000000
= 7650mL
3. 1 day = 86400s
2.5 days = 2.5 × 86400
= 216000 seconds
4. 1 week = 10080minutes
1.000weeks is equivalent to 1 week, hence there are 10080minutes in 1.000week.
5. 1minute = 60seconds
40.0minutes = 40 × 60
= 2400seconds.
6. 1 inch = 2.54cm
68.5inches = 68.5 × 2.54
= 173.99cm
7. 1Ib = 16oz
155Ibs = 155 × 16
= 2480 oz
1 oz = 28.34 g
2480oz = 2480 × 28.34
= 70283.2g
8. 1 foot = 12 inches
450 feet = 450 × 12
= 5400inches
1 inch = 0.0254metres
5400 inches = 5400 × 0.0254
137.16metres
9. 1 metre = 0.000621 mile
8000 metres = 8000 × 0.000621
= 4.968miles
10. 1 kilometers = 1000 metres
5km = 5 × 1000
= 5000metres
1 metre = 0.000621 mile
5000metres = 5000 × 0.000621
= 3.105miles
What is the mass of 4.39 mol Na?
Answer:
101 g Na
Explanation:
To convert between moles and grams, you have to use the molar mass of the substance. The molar mass of sodium is 22.99 g/mol. You use this as the unit converter.
[tex]4.39molNa*\frac{22.99gNa}{1molNa} = 100.9261gNa[/tex]
Round the number to the lowest number of significant figures; 101 g Na.
The mass of 4.39 moles of sodium (Na) is 100.97grams.
HOW TO CALCULATE MASS:The mass of a substance can be calculated by multiplying the number of moles in the substance by its molar mass. That is;Mass = no. of moles × molar mass
According to this question, there are 4.39 moles of Na. The molar mass of Na is 23g/mol.Mass of Na = 4.39 × 23
Mass of Na = 100.97grams.
Therefore, mass of 4.39 moles of sodium (Na) is 100.97grams.
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According to Dalton’s atomic theory, what are elements and what makes one element different from another?
Dalton was a chemist who discovered the “law of multiple proportion” in chemical reaction in early nineteenth century. For example, element of tin, he observed, interacted with oxygen to produce two different masses but in proportion 1:2. (Now, this is known to correspond to the formation of tin-monoxide and tin-dioxide, with one and two atoms of oxygen, respectively.)
From such and related studies, he proposed his theory of chemical elements: (a) that all elements are composed of ‘atoms’, the hypothetical indivisible constituents of matter of the ancient Greek thinkers, like, Democritus, and (b) that the elements differ from one another due to the atoms of different masses and sizes that constitute an element.
The modern theory of chemistry says that an element consists of an atom that consists of a heavy nucleus with positively charged ‘protons’ (and most often also the neutral particles called ‘neutrons’) at its center and, an equal number of negatively charged (and much lighter) ‘electrons’, distributed around it in discrete energy shells. Further, the elements differ from one another by the number of positively charged protons in their nucleus, the so-called atomic number, Z, of an atom. Finally, molecules are formed as well as chemical reactions take place, through the exchange or transfer of the electron(s) in the outermost shells of the reacting atoms (and/or molecules).
At every depth, soil composition remains the same.
O
True
O False
Answer:
false
Explanation:
Hope the answer was usefull for us
Answer:
false. there is the surface soil, which has a lot of partly decayed stuff, topsoil, which has minerals and organic material, subsoil, which is made from sand, silt, and clay that hasn't been broken down, and parent material, which is the place where not much living things live in, except for gigantic tree roots. then there is the bedrock, which is; you guessed it:rock entirely.
Explanation:
marine science flvs 2.03
can someone please send the answers for this!!!
Answer:
101
Explanation:
Answer:
Explanation:
Describe the relationship between an element and a compound.
Answer:
An element is a material that consist of a single type of atom . each atom type contains same number of protons . chemical bonds link elements to form more complex molecules called compound A compound consist of two or more elements held together by covalent or ionic bonds.
are you clear?
Chromium-48 decays. After 6 half-lives, what fraction of the original nuclei
would remain?
Answer:
The fraction of original nuclei remaining is 1.5625
Explanation:
WHOEVER ANSWERS THIS QUESTION FIRST WILL GET BRAINLIEST!!
PLEASE HURRY!!!
Select 5 elements that form ions in an isoelectronic series with the noble gas Argon. Support your claim with evidence and scientific reasoning.
Answer:
Explanation:
How many meters is a 50 yards olympic size swimming pool?
Answer:
An official Olympic Sized pool is 50 meters long by 25 meters wide.
Explanation:
What do these two changes have in common?
sauce burning on a stove
dry ice sublimating and becoming a gas
Select all that apply.
Both are caused by heating.
Both are only physical changes.
Both conserve mass.
Both are chemical changes.
Answer:
Both are caused by heating and both are physical and chemicals.
Explanation:
The similarity between the two changes that have common things are
A. Both are caused by heating.
C. Both conserves mass.
D. Both are chemical changes.
What are chemical and physical changes?The term “physical change” refers to a change in an object's appearance. When there is a change in the surroundings of the object, such as a rise in temperature or pressure, a physical change takes place.
When candles are burned, the wax melts, but as soon as the temperature drops, the wax hardens and solidifies once more.
Here, chemical changes happen because these changes can not be undone again. When a substance changes their appearance, they always have the same mass.
Thus, the correct options are A. Both are caused by heating, C. Both conserve mass, and D. Both are chemical changes.
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Which of the following is an example of how pictures of a planet's surface can provide evidence about the planet's natural resources?
Answer:
it can show how much green is left. and how climate change is going, and the cloud shows how much oxygen is left in the air.
at room temperature oxygen gas travels at 393.5 meters per second. How fast does oxygen travel in mile per hour ?
Answer:
Oxygen travels in 1,416,600
Explanation:
A scientist is examining a mixture of nitrogen, hydrogen, and ammonia. The individual pressures that are exerted by nitrogen and hydrogen are 0.26 atm and 0.28 atm, respectively. If the total pressure is 0.90 atm, what is the partial pressure of ammonia? Use P subscript T equals P subscript 1 plus P subscript 2 plus P subscript 3 plus ellipses plus P subscript n.. 0.27 atm 0.36 atm 0.54 atm 0.90 atm
Answer: 0.36 atm
Explanation:
According to Dalton's law, the total pressure is the sum of individual pressures.
[tex]p_{total}=p_1+p_2+p_3[/tex]
Given : [tex]p_{total}[/tex] = total pressure of gases = 0.90 atm
[tex]p_{N_2}[/tex]= partial pressure of nitrogen = 0.26 atm
[tex]p_{H_2}[/tex] = partial pressure of hydrogen = 0.28 atm
[tex]p_{NH_3}[/tex]= partial pressure of ammonia = ?
putting in the values we get:
[tex]0.90=0.26 +0.28+p_{NH_3}[/tex]
[tex]p_{NH_3}=0.36atm[/tex]
Thus the partial pressure of ammonia is 0.36 atm
Answer:
B) 0.36 atm
Explanation:
Explain what happens if the nucleus, of an atom, becomes unstable.
Answer:The unstable nucleus of radioactive atoms emit radiation. When this occurs, a new atom and element are formed. This process is called radioactive decay. It continues until the forces in the unstable nucleus are balanced.
Explanation:
Which of the following presents the steps of the engineering process in the correct order?
1.Identify a need, make a plan know the background, do the work, test the results, evaluate and redesign
O
2. dentify a need, know the background, do the work, make a plan, evaluate and redesign, test the results
3. Know the background, identify a need, make a plan, evaluate and redesign, do the work, test the results
4.Identify a need, know the background, make a plan, do the work, test the results, evaluate and redesign
Answer:
4
Explanation:
I got it right
The engineering process in the correct order "Identify a need, know the background, make a plan, do the work, test the results, evaluate and redesign"
What is engineering process?At an industrial level, process engineering is just the understanding as well as application of fundamental natural principles and laws that allow people to transform raw materials along with energy into products that seem to be beneficial to society.
What is redesign?Redesign, in terms of building, is the procedure of finding a solution to such a project. this includes then writing instructions that allow such a solution to be built.
The engineering process in the correct order "Identify a need, know the background, make a plan, do the work, test the results, evaluate and redesign"
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Type the correct answer in each box.
Which chemical symbols will complete the equation for this single displacement reaction?
2NaBr + Cl2 → 2 __ __ + __ 2
Answer:
2Naci+Br2
Explanation:
i hope it is help full
Answer:
Na//Cl//Br
Explanation:
In this chemical formula: 3NH4 (ammonium) This chemical formula means there are 3 _____________ ___________, and 4 __________ ________ in each molecule.
Answer:
hope it helped you
Explanation:
3 atoms of nitrogen and 4 atoms of hydrogen in each molecule
The chemical formula 3NH4 means there are 3 atoms of nitrogen and 4 atoms of hydrogen in each molecule.
What are chemical reaction?Chemical reaction is defined as a process in which one or more substances, the reactants, are converted into one or more different substances, the products.
A chemical reaction rearranges the constituent atoms of the reactants to create different substances as products.
There are five main types of reactions.
Combination reaction - A combination reaction is a reaction in which two or more substance combine to form a single new substance also known as synthesis reaction.Decomposition reaction - A decomposition reaction is a reaction in which a compounds break down into two or more simpler substance.Single replacement reaction - A single replacement reaction is a reaction in which one element replaces a similar element in a compound.Double replacement reaction - A double replacement reaction is a reaction in which the positive or negative ions of to ionic compounds exchange places from two new compound.Combustion reaction - A combustion reaction is a reaction in which a substance reacts with oxygen gas, releasing energy in the form of heat and light.Thus, the chemical formula 3NH4 means there are 3 atoms of nitrogen and 4 atoms of hydrogen in each molecule.
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PLS ANSWER!! ASAP!!! 10 POINTS!!
Why are metals in Group 1A so reactive?
A. These metals need one electron to complete their outer shell.
B. These metals need two electrons to complete their outer shell.
C. These metals have one electron in their outer shell.
D. These metals have two electrons in their outer shell.
Answer:
the answer is = a. these materials...
The metals of Group 1A are so reactive because these metals have one electron in their outer shell. Therefore, option (C) is correct.
What are the metals of Group 1A?The elements of Group 1A of the periodic table are also called alkali metals. The seven elements of group 1 A include hydrogen(H), lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr).
These are low-melting, extremely reactive, glossy metals that oxidize when exposed to air. When dissolved in water, these metals or their oxides produce a basic solution. Because of their high reactivity, alkali metals are instead found as ionic compounds (except hydrogen).
The general electronic configuration of the alkali metals is ns¹. As they lose one electron from their valence shell they acquire the nearest noble gas configuration, therefore they are very reactive.
The alkali metals are all lustrous, soft, and extremely reactive metals at normal temperature and pressure that quickly lose their valence electrons to create cations with charge +1.
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how many atoms in a chair
Answer:
100 trillion atoms are in one cell and so just find how many cells are in a chair and then take 100xthe number and you get your answer
Explanation:
There are uncountable atoms which are present in a chair depending on it's size.
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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Mr. Hackworth toasts a marshmallow over a fire. The outside of the marshmallow turns black, a new substance with new properties is created on the outside of the marshmallow, and the marshmallow gives off an odor. What type of change occured?
A
Physical, because color is a physical property.
B
Physical, because a new substance was created, smell, and color change.
C
Chemical, because a new substance was created, smell, and color change.
D
Chemical, because color is a chemical property.
Answer:
C
Explanation:
This is a chemical property because a catalyst is added(fire). Without a catalyst a marshmallow would stay a marshmallow. The sugar caramelizes(this is not physical because sugar is burning)
how to check atomic mass?
Answer:
There are multiple ways to check mass but I'll tell you one. Look below
Explanation:
One easy way of checking atomic mass is by adding protons and neutrons.
For example:
We have 5 protons and 4 neutrons.
5+4=9
I hope this helps (: