Answer:
First 20 Elements
Atomic Number Element Symbol
17 Chlorine Cl
18 Argon Ar
19 Potassium K
20 Calcium Ca
two example of solid -solid solution
Answer:
Steel — in steel, there is a solid-solid solution of iron and carbonBrass — in brass, there is a solid-solid solution of zinc and copper.Second ionization energies are always _____ than first ionization energies because the remaining electrons are attracted _____ strongly as the positive charge on the ion increases. A large jump in ionization energies is always observed after the _____ electrons have been removed.
mention four states of matter and explain and give examples
Answer:
solid: ice.
liquid: water
gas: methane
plasma: lightning
Explanation:
Why is it difficult to classify dissolving as simply a physical or a chemical change?
It is difficult to classify dissolving as physical or chemical change because at some point dissolving produce new substance which can not be reversed while at some point no new substances are produced but and the process is reversed.
Physical change is a change in which no new substance is formed and the process is easily reversible. For example, the dissolution of salt in water is a physical change since we can reverse the process to obtain salt and water.
Water + Salt <=> Salt Solution
Chemical change is a change in which new substance is formed and and the process is not reversible. For example, the dissolution of metal in acid is a chemical change since we can not reverse the process to obtain the metal.
Acid + metal —> Salt + hydrogen gas
2Na + 2HCl —> 2NaCl + H₂
Thus, we can see that it is difficult to classify dissolving as a physical or a chemical change.
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Can someone explain this to me, please?
A stable sodium atom has 11 electrons. The sodium isotope [tex]Na_{24}[/tex] has:
A.) How many protons?
B.) How many neutrons?
C.) An atomic number of what?
Answer:
Isotopes have same atomic numbers, no. of protons and no. of electrons. Only their no. of neutrons and atomic mass are changed.
Na - 24:
Atomic Mass = 24
Atomic No. = 11
Hence,
No. of protons in Na-24 = 11
No. of neutrons = Atomic Mass - Atomic Number
No. of neutrons = 24 - 11
No. of neutrons = 13
Atomic Number = 11
[tex]\rule[225]{225}{2}[/tex]
Hope this helped!
~AH1807Peace!To reduce the costs of extracting aluminum, what must be added to it to reduce the melting point?
Explanation:
To reduce costs, powdered aluminium oxide is dissolved in molten cryolite. This ionic compound melts at a lower temperature than aluminium oxide, reducing costs.
i got the total but can’t get these ???
Answer:
Volume of heptane in cylinder = 51.2mL
Volume of water = 33mL
Explanation:
Density(g/mL) = mass/ Volume
》Volume = mass/ Density
Please prompt me if I'm wrong in my workings. Hope this helped.
Is it possible to prove that something is real or true of you can’t directly observe it? If no, why not? If yes, how would you do that?
Answer:
yes
Explanation:
Anything that is verifiable and repeatable is likely to be true. If not verifiable and repeatable, then it may well be completely false, or at least partially false.
This holds for much more than just religious beliefs. What about political thought? One perfect example was when President Obama was pushing his ACA (Obamacare). His facile claim was that with medical coverage for all, the costs of health care would go down. Because people would take better care of themselves, avoiding those major medical bills. But that's just a banality, right? Just words that sound good. I'm not saying that morally, universal health care is wrong. I am saying, don't assume something to be true just because it sounds good. (Of course, health care costs went up, not down.)
Is it true that if you get your car washed every week, it will last longer and cost you less in the long run? Of course not. But it sounds good. People will nod their heads in mindless, lazy agreement. You'll have a cleaner car, you will most likely pay more, and it may last less long, depending on any number of factors. Exactly the same as health care
In the single replacement reaction between magnesium and HCl what reaction resulted from inserting the lit splint into the test tube mouth ?
Answer:
Magnesium reacts with dilute hydrochloric acid in a conical flask which is connected to an inverted measuring cylinder in a trough of water. The volume of hydrogen gas produced is measured over a few minutes, and the results are used to plot a graph
Explanation:
Hope it will help you
Answer:
Adding magnesium metal to hydrochloric acid produces hydrogen gas. The magnesium dissolves to form magnesium chloride, MgCl2.
burning. If you observe a gas forming, test for its identity by inserting a glowing wood splint into the mouth of the test tube. ... This is a “glowing splint.” If the splint continues to glow, oxygen gas is present. Do not put the splint into the solution.
hope it's help you....!!!!!!
#rishu
A student conducts an experiment to determine the speed of a toy car at the bottom of a ramp after it is released from different heights on the ramp. The student makes one measurement for each height.
What is one way that the student could improve the experiment?
use a different ramp for each height
perform multiple trials for each release height instead of just one
use a different timer for height
perform one trial for each measurement but use a different car for each height
Answer:
perform multiple trials for each release height instead of just one
Explanation:
How does water vapor in the air change state below the freezing point
Answer:
Water vapor molecules in the air near the can cooled when energy from the air transferred to the cold can. These water molecules slowed down, condensed to liquid water, and then froze to become ice. Your can might have some water and some ice on the outside of it.
Explanation:
where do we get the mass number
Explanation:
Mass number is the sum of the numbers of protons and neutrons present in the nucleus of an atom.
How many atoms of each elements are in three molecules
Answer:
Molecules of compounds have atoms of two or more different elements. For example, water (H2O) has three atoms, two hydrogen (H) atoms and one oxygen (O) atom.
Explanation:
Distillation can be separated in what technique?
A. Chemical
B. Physical
Answer:
B. Physical process is the way distillation can be separated.
The molar mass of C3H8O2 (three significant figures) is ________.
Answer:
[tex]\boxed {\boxed {\sf 76.1 \ g/mol}}[/tex]
Explanation:
We are asked to find the molar mass of C₃H₈O₂.
The molar mass is the mass of 1 mole of a substance. The values are found on the Periodic Table because they are equivalent to the atomic masses. However, the units are grams per mole instead of atomic mass units.
Look up the molar masses of the individual elements in the compound: carbon, hydrogen, and oxygen.
Carbon (C): 12.011 g/mol Hydrogen (H): 1.008 g/mol Oxygen (O): 15.999 g/molLook at the subscripts in the formula. There is a subscript of 3 after C, another of 8 after H, and another of 2 after O. Therefore, there are 3 moles of carbon, 8 moles of hydrogen, and 2 moles of oxygen in every mole of the compound. Multiply the element's molar mass by the subscript.
C₃: 12.011 * 3 = 36.033 g/molH₈: 1.008 * 8 = 8.064 g/mol O₂: 15.999 *2=31.998 g/mol[tex]36.033 + 8.064 + 31.998 = 76.095 \ g/mol[/tex]
Round to the 3 significant figures. For the number we calculated, that is the tenths place. The 9 in the hundredth place to the right tells us to round the 0 up to a 1.
[tex]76.1 \ g/mol[/tex]
The molar mass of C₃H₈O₂ is approximately 76.1 grams per mole.
Note:-
Approximate Values taken for Atomic masses
Solution:-
[tex]\\ \rm\longmapsto C_3H_8O_2[/tex]
C=12uH=1uO=16u[tex]\\ \rm\longmapsto 3(12u)+8(1u)+2(16u)[/tex]
[tex]\\ \rm\longmapsto 36u+8u+32u[/tex]
[tex]\\ \rm\longmapsto 44u+32u[/tex]
[tex]\\ \rm\longmapsto 76u[/tex]
[tex]\\ \rm\longmapsto \approx76g/mol[/tex]
Assertion : When the added electron goes to smaller n=3 quantum level, the electron-
electron repulsion is much less.
Reason: The added electron occupies a smaller region of space .
It is due to low volume of electron that causes large distance between two electrons.
When the added electron goes to smaller quantum level, the repulsive force between two electrons is less because the electron which is added occupies small space due to less volume so there is a large distance between two electrons that leads to less force of repulsion.
If the electron has more volume so it occupies more space and there will more repulsive force between two electrons so that's why we can say that the smaller volume of electron is the reason of less repulsive force.
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Find the density of mercury if 205 mL has a mass of 2790 g round your answer to the nearest 0.1 g
Answer:
13.6g/L
Explanation:
The formula for density is D=m/V
D = Density in grams per liter (g/L)
m = Mass of sample in grams
V = volume of sample in liters
Convert 205mL to Liters as follows:
205mL (1L/1000mL) =0.205L
then simply plug into the equation for density:
2790g/0.205L = D= 13.6g/L
diantara senyawa di bawah ini yang tidak berisomer dengan n- heksana adalah
a) 2 metil pentana
b) 2 etil pentana
c) 2,2 dimetil butana
d) 2,3 dimetil butana
e) 3 metil pentana
Complete the following sentences by writing in the correct word.
In a neutral atom, the number of electrons must be the same as the number of
.
The subatomic particle in an atom with no charge is the
.
The number of protons in an atom is the
number.
The total number of protons and neutrons in an atom is the
number.
1)proton number
2)neutron
3)(Z)
4)mass
is water?
A. a substance made up of two different elements (hydrogen and oxygen)
B. an element
Answer:
A substance made up of two different elements (hydrogen and oxygen)
May someone help me with the answer to this question I’ve been stuck on it
Explanation:
No, that would be incorrect
Answer:
There arre two main parts of the atom, the nucleus and the orbital rings. The three subatomic particles are contained in each of these, the proton and neutron together in the nucleus and the electrons orbiting in the rings.
Most electrochemical cells are the site of redox reactions. They contain 2 electrodes, the ______ where reduction occurs and the _______
A. cathode, anode
B. None of these
C. anode, galvanode
D. anode, cathode
Answer:
A.cathode,anodeExplanation:
positive and negative
pls make me the brainliest9.11 x 10^3 in standard notation?
Answer:
the right answer is 9110
define mass number in your own words
Answer:
The total number of protons and neutrons in the nucleus of an atom is called mass number.
Answer:
mass number also called nucleon number and it's the total number of neutron and proton in an atomic nucleus.
In a chemical reaction, reactants are the substances that you _________ with and the products are the substances that you _________ with
Answer:
Start, Finish
Explanation:
Reactants react. Products are the end result.
Why does the author include information about bread and sandwich wrappings in the article?
(A) to show that the scientific method is often used to understand things about food
(B) to provide an example of something that can be tested by the scientific method
(C) to demonstrate the problems that can be caused by improper seals and wrappings
(D) to help evaluate how the weight of bread can show how much moisture it has
Answer:
what is the story about actually.i think it's from ur lesson
Explanation:
certain breads mold easily...(fact)..
especially white bread., when exposed to any moisture, from refrigeration, or freezing..
when taken out of (cold environment), humidity in air causes molding because you take it from cold to/warm environment.
check expiration dates, keep refrigerated, and inspect 4 molding. Companies like WMART, buy in bulk, when on shelf, defrosts,, then has molding within expiration dates..
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anyone know valency of phosphide and phosphite please tell me and also they are not same .If you know can i get their symbol too please
i found this. there's more coming up
can someone suggest me topics for chemistry project work?
Answer:
Which
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Which statement about metals and nonmetals is correct? (1 point)
O Metals and nonmetals can both be found in any column of the periodic table.
O Most metals are a solid under normal conditions, and most nonmetals are a liquid.
O Metals tend to be poor conductors of electricity, while nonmetals are strong conductors of electricity.
O Metals can be hammered into thin sheets, and nonmetals are brittle
Answer:
The answer is the 4th one
The statement about metals and nonmetals that is correct is: "The Metals can be hammered into thin sheets, and nonmetals are brittle."
Metals are found mostly towards the left hand side of the periodic table. Non-metal character increases as you move towards the right hand side of the table.
One common property of metals is that they are malleable; this means that they can be hammered into sheets while a common property of nonmetals is that most of them are brittle.
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