The Nobel gases, Group 8 elements have the smallest atomic radIi in the periodic table.
Atomic radius decreases as you move across a period. This is because Within a period, a new electron is being added to the same shell , and at the same time a new proton is added , This causes an attraction and causes the electron to pull nearer to the nucleus causing the radius to shrink and reduce in size.
In decreasing order of atomic radius, we have alkali metals>halogens> transition metal > Nobel gases
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Explain why atoms in group 2a are likely to form ions with plus two charge explain why why atoms in group 7a are likely to form ions with a minus one charge
Answer:
Atoms in group 2a are likely to form ions with a +2 charge because they have two valence electrons, both of which experience a very weak pull from the nucleus due to electron shielding. This causes the atoms to be easily pulled away from the nucleus, creating the +2 ions we see in nature.
Atoms in group 7a are likely to form ions with a -1 charge because they are one electron away from completing their outermost shell. The large number of protons in the middle of these atoms also causes the valence electrons to experience a stronger net force. This force also pulls strongly on the valence electrons of other atoms, causing the -1 ions we see in nature.
Calculate the number of S atoms in 0.670 mole of S.
Answer:
4.03 × 10²³ atomsExplanation:
The number of S atoms can be found by using the formula
N = n × Lwhere n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
N = 0.67 × 6.02 × 10²³
We have the final answer as
4.03 × 10²³ atomsHope this helps you
MULTIPLE CHOICE: For a combustion system, incorrect statement is?
Answer:
I THINK it's D, I could be incorrect, however.
Explanation:
C3H8O, as it is flammable, and thus I wouldn't imagine it being a product of combustion. I could be incorrect, so take my answer with a grain of salt.
Iodine 131, cesium 137, and strontium 90 are all considered isotopes. What are isotopes?
Answer:
Isotopes are variants of an element, where the number of neutrons is different but its number of protons stay the same.
Explanation:
If the number of protons had changed then it would just be a different element.
Electron number changing simply adds charge to the atom, and doesn't change it or anything.
PLS GIVE BRAINLIEST
Answer:
Isotopes are one of two or more forms of the same chemical element.
Explanation:
Different isotopes of an element have the same number of protons in the nucleus, giving them the same atomic number,but a different number of neutrons giving each element isotope of a different atomic weight.
who established the two important laws of chemical combination combination state them
Answer:
Antoine Lavoisier
1) Law of Conservation of Mass
French chemist, Antoine Lavoisier in 1789, studied this law. This law states that “In all physical and chemical changes, the total mass of the reactants is equal to that of the products” or “Mass can neither be created nor destroyed.”
How long will it take to deposit 6.32 g of copper from a CuSO4(aq) solution using a current of 0.554 amps
Answer:
34672.96 s
Explanation:
m = Mass of copper = 6.32 g
M = Molar mass of copper = 63.5 g/mol
F = Faraday constant = 96500 C/mol
The electrode equation would be
[tex]Cu^{2+}(aq)+2e^{-}=Cu(s)[/tex]
Number of electrons = 2 = e
I = Current = 0.554 A
t = Time taken
Charge would be
[tex]Q=\dfrac{m}{M}eF\\\RightarrowQ=\dfrac{6.32}{63.5}\times 2\times 96500\\\Rightarrow Q=19208.82\ \text{C}[/tex]
Charge is given by
[tex]Q=It\\\Rightarrow t=\dfrac{Q}{I}\\\Rightarrow t=\dfrac{19208.82}{0.554}\\\Rightarrow t=34672.96\ \text{s}[/tex]
Time taken to deposit the copper is 34672.96 s.
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Question 10 of 12- POS
GR8 Sci U03 USA FY21 Question: 1-10
Hannah added a silvery white metal to a beaker of cold water and noticed that gas bubbles were given off and a different substance formed. When she repeated the activity with hot water she noticed the gas bubbles were
released much more rapidly. Which statement best explains why the reaction occurred faster in hot water?
M
The correct answer is Hot water increases the collision rate of molecules, causing the reaction to occur faster.
Explanation:
Temperature is directly related to the kinetic energy or movement of molecules in a substance. In this context, a higher temperature leads to more kinetic energy or more collision between molecules. At the same time, a chemical reaction involves molecules of two or more substances colliding and creating bonds to form new substances. This implies an increase in temperature means molecules colliding faster, new substances forming in a shorter time, and therefore a faster chemical reaction. According to this, the first answer is correct.
Rank the following from least to greatest electron affinity: Carbon (C), Nitrogen (N), Oxygen (O).
Group of answer choices
O < N < C
C < N < O
N < C < O
C < O < N
Answer:
C < N < O.
Explanation:
Hello!
In this case, since the electron affinity is a periodic property of elements indicating how likely is for the element to gain one electron, which is also related to the electronegativity, we can notice that fluorine is the most electronegative element or also, the element with the highest electron affinity whereas francium is the least electronegative element.
Therefore, we can infer that the electron affinity or electronegativity, increases from left to right and from bottom to top in the periodic table, it means that among carbon, nitrogen and oxygen, the element with the greatest electron affinity is oxygen, then nitrogen and finally carbon with the least one, thus answer is C < N < O.
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Sweat is made up of all EXCEPT what?
*
A.Sugar
B.Salt
C.Urea
D.Urine
How many moles of NaCl , if mixed with excess Pb2+ ions in solution, would be needed to form 45.5 g of PbCl2 ?
The number of mole of NaCl needed to react with excess Pb²⁺ to produce 45.5 g of PbCl₂ is 0.328 mole
We'll begin by calculating the number of mole in 45.5 g of PbCl₂. This can be obtained as follow:
Mass of PbCl₂ = 45.5 g
Molar mass of PbCl₂ = 207 + (35.5×2) = 278 g/mol
Mole of PbCl₂ =?Mole = mass / molar mass
Mole of PbCl₂ = 45.5 / 278
Mole of PbCl₂ = 0.164 mole Finally, we shall determine the number of mole of NaCl needed to produce 0.164 mole (i.e 45.5 g) of PbCl₂. This can be obtained as follow:2NaCl + Pb²⁺ —> PbCl₂ + 2Na⁺
From the balanced equation above,
2 moles of NaCl reacted to produce 1 mole of PbCl₂
Therefore,
Xmol of NaCl will react to produce 0.164 mole of PbCl₂ i.e
Xmol of NaCl = 2 × 0.164
Xmol of NaCl = 0.328 mole
Thus, the number of mole of NaCl needed for the reaction is 0.328 mole
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1. How many Chromium atoms are found in 25.8 milligrams of Chromium?
Answer: 51.9961 g/mol, don't know if it helps :)
Explanation:
Answer:
Chromium is a steel-gray, lustrous, hard metal that takes a high polish, is fusible with difficulty, and is resistant to corrosion and tarnishing.
The most common oxidation states of chromium are +2, +3, and +6, with +3 being the most stable. +4 and +5 are relatively rare. Chromium compounds of oxidation state 6 are powerful oxidants.ion:
2. Enumerate four Reactive Oxygen Species (ROS)
Answer:
Examples of ROS include peroxides, superoxide, hydroxyl radical, singlet oxygen, and alpha-oxygen.
An egg sinks in fresh water but it floats on salty water.why?
How does the density and distribution of your “stars” change as the balloon expands?
Answer:
The Universe is constantly expanding and as it expands the stars and objects in space move farther apart, just like the points on the balloon when air is blown into it. Density and distribution of "stars" as the balloon expands because when volume increases the density will increase.
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Determine the density of CO2 gas at STP
Answer:
the density of CO2 gas at STP is 1.96 g/l.
Carbon doesn't have a charge because it doesn't generally share or donate electrons.
*
True
O
False
Answer:
Correct me if i'm wrong but i'm pretty sure its FALSEExplanation:
Its because In a single bond, two carbon atoms share one pair of electrons. In a double bond, they share two pairs of electrons, and in a triple bond they share three pairs of electrons.What are the starting substances (molecules) in a chemical equation called?
Answer:
A chemical reaction is the process in which atoms present in the starting substances rearrange to give new chemical combinations present in the substances formed by the reaction. These starting substances of a chemical reaction are called the reactants, and the new substances that result are called the products.
2. Molecular solutions do not conduct electricity because they contain: *
(1 Point)
The ions are able to move freely from one place to another. So that they conduct electricity. But the molecular solutions does not electricity.
What is a molecular solution?The molecular solution is composed of molecules and consists of non - metallic atoms. These atoms are held together by the covalent bonds. The flow of charged particles is responsible for the conduction of electricity. If there is no flow of electrons or ions then there will be no electricity.
In the molecular solutions, the molecules present are not dissociated into respective ions. Since the molecules are not converted into the charged particles no electricity is produced.
A molecular solution is regarded as a non-electrolyte which does not contain ions. But electrolytes are dissociated into ions and thereby conducts electricity. So all electrolytes are good conductors of electricity.
Thus molecular solution does not contain ions.
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A rigid 3.80 L sealed vessel contains 0.650 mol Ne, 0.321 mol Kr, and 0.190 mol Xe. Find the density of the mixture in g/L.
Answer:
17.09g/L
Explanation:
Density = total mass of elements/ volume
We need to find the mass of each mixture constituents using their molar mass:
mole = mass/molar mass
For Neon (Ne) which contains 0.650mol;
0.650 = mass/20.18
mass = 0.650 × 20.18
mass = 13.12g
For Krypton (Kr) which contains 0.321mol;
0.321 = mass/83.79
mass = 0.321 × 83.79
mass = 26.89g
For Xenon (Xe) which contains 0.190mol;
0.190 = mass/131.3
mass = 0.190 × 131.3
mass = 24.95g
Total mass = 13.12g + 26.89g + 24.95g = 64.96g
Density = total mass / volume
Density = 64.96g / 3.80L
Density of the mixture = 17.09g/L
The diagram shows the setup of an experiment. A few observations of the experiment are listed in the table below the diagram.
A beaker filled three-fourths with a liquid labeled colorless silver nitrate solution is shown. A small strip is shown inside the beaker. The strip is labeled copper strip. The title of the image is Experimental Setup.
Experimental Observations
Observation Description
1 Solution turned blue
2 Gray particles were deposited on the edge of the strip
Which of the following is the correct explanation for one of the given observations?
Observation 2 is a result of nitrate ions moving into the solution.
Observation 1 is a result of copper ions moving into the solution.
Observation 1 is a result of silver atoms losing one electron.
Observation 2 is a result of silver ions losing one electron.
Copper is higher than silver in the electrochemical series hence copper displaces silver in the electrochemical series.
The solubility of a metal in another is determined by their relative positions in the electrochemical series. The metals that are higher above in the electrochemical series displaces the metals that are lower in the electrochemical series.
Copper is higher than silver in the electrochemical series hence copper displaces silver in the electrochemical series. Therefore, the correct explanation for an observation is that;
Observation 1 is a result of copper ions moving into the solution.Learn more: https://brainly.com/question/9743981
Answer:
Observation 1 is a result of copper ions moving into the solution.
Explanation:
got it right on the test
The equation 2NaNO3 + CaCl2 - 2NaCl + Ca(NO3)2 is balanced. How many atoms of sodium (Na) are there on either side of the equation? one two four six
Question: How many atoms of sodium (Na) are there on either side of the equation?
Options: A) one B) two C) four D) six
Correct answer: D) six
Answer:
It is NOT six, i took the test and got it wrong. The CORRECT answer is 2
Explanation:
At the Sparta Fault in Greece, the hanging wall is below the footwall. This type of fault is called a .
Answer:
1 a
Explanation:
10. INFER: Why can the reactant in a
decomposition reaction never be an element?
Answer:
Because elements cannot decompose
Explanation:
Elements are distinct substances that cannot be split-up into simpler substances. Such substances are only made up of one atom.
An atom is the smallest indivisible particle of substance that can take part in chemical reaction. By chemical means, an atom cannot be broken down. Therefore, an element cannot break down during decomposition reaction. A decomposition reaction is one in which a substance breaks down into two or more products.How much water must be added to 424 mL of 0.189 M HCl to produce a 0.140 M solution?
Answer:
Volume of water added = 148.4 mL
Explanation:
Given data:
Initial volume = 424 mL
Initial molarity = 0.189 M
Final molarity = 0.140 M
Volume of water added = ?
Solution:
Formula:
M₁V₁ = M₂V₂
0.189 M×424 mL = 0.140 M×V₂
V₂ = 0.189 M×424 mL /0.140 M
V₂ = 80.136 M.mL / 0.140 M
V₂ = 572.4 mL
Final volume of solution is 572.4 mL.
Volume of water added = Final volume - initial volume
Volume of water added = 572.4 mL - 424 mL
Volume of water added = 148.4 mL
Using the VSEPR model, the molecular geometry of the central atom in ClO3- is:_____.a. bent. b. linear. c. trigonal pyramidal. d. trigonal planar. e. tetrahedral.
Answer:
D
Explanation:
it is trigonal planar, because central atom does not have the lone pairs, equal repulsion
The molecular geometry of the central atom in ClO3- will be triangular pyramidal.
What is VSPER model?The geometry of molecular structures can be predicted using the chemical model known as the valence shell electron pair repulsion hypothesis based on the number of electron pairs surrounding the core atoms of the molecules.
Since ClO3- has a steric number of 4 (one unpaired pair as well as three bonded pairs), can infer that its molecular shape is triangular pyramidal. Its electrical form is tetrahedral, as shown by the Lewis structure above.
Therefore, the correct answer will be option (c).
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how many moles of ethanol C2H6O, are in a 10.0g sample
Answer: 0.217 mol
Explanation:
To find the amount of moles in a 10 g sample, we need the molar mass of ethanol.
Molar Mass: 46.07 g/mol
Now that we have the molar mass, we can find moles.
[tex]10.0 g*\frac{1mol}{46.07g}=0.217 mol[/tex]
We know that there are 0.217 mol in a 10.0 gram sample.
Identify at least 5 pure substance found in nature,in the supermarket, grocery storeand even at your home.use the table below to explain your answer based on appearance, separating technique, boiling and melting point.
Answer:
Explanation:
1) Pure substance: Water (found at home)
Appearance: It is homogeneous since it is a single substance that appears as liquid. Homogeneous is when the components of a substance are in a single phase
Separating technique: It's component cannot be separated by physical means
Boiling point: Water boils at 100 °C
Melting point: Water melts/freezes at 0°C
2) Pure substance: Table salt (found at home)
Appearance: It is also homogeneous as it is a single substance that is solid. Separating technique: It's component cannot be separated by physical means
Boiling point: Water boils at 1,465 °C
Melting point: Water melts/freezes at 801 °C
3) Pure substance: Butter (found at home and grocery store)
Appearance: It is homogeneous even though it contains different components
Separating technique: It's component can be separated by physical means since butter is an emulsion of fat in water. The 15% water content can be evaporated/distilled out at 100 °C
Boiling point: Butter starts boiling at about 110-120 °C
Melting point: It melts at about 37 °C
4) Pure substance: Candle (wax) (found at home and grocery store)
Appearance: It is homogeneous
Separating technique: It's component cannot be separated by physical means
Boiling point: It starts boiling around 370 °C
Melting point: It melts at about 37 °C
5) Pure substance: table sugar/sucrose (found at home, grocery stores and in supermarkets)
Appearance: It is homogeneous
Separating technique: It's component cannot be separated by physical means
Boiling point: It starts boiling around 697 °C
Melting point: It melts at about 186 °C
A pure substance is an homogeneous material, having a composition, and
properties that are consistent through out the material.
The chemical properties of a pure substance are defined, such as the
products of its reaction can be predictable.
A chemical is pure when it consist of a single type of particle such as an
element, a molecule or a compound.
The five pure substances are presented as follows;
[tex]\displaystyle\begin{tabular}{|l|l|l|l|l|}\underline{Pure \ Substances}&\underline{Appearance}&\underline{Separaing Tech}&\underline{Boiling \ Point}&\underline{Melting \ point}\\1. Diamond&Translucent \ solid&Inseparable&3550^{\circ}&4830^{\circ}\\2. Table \ salt&White\ crystals&Insepble&801^{\circ}&1413^{\circ}\\3. Water&Tran parent \ liquid&Insepble&0^{\circ}&100^{\circ}\\4. Sugar&Whilte \ crystals&Heating&Decomposes&186^{\circ}\\5. Gold&Yellowish \ metal&Inseparable& 2700^{\circ}&1064^{\circ}\end{array}[/tex]
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The pressure of a compressed gas is 1.45 atm. What is this pressure in kPa
Answer:
1.45 Atmospheres = 146.92125 Kilopascals, or about 146.9 Kilopascals
Explanation:
1 Atmosphere = 101.325 Kilopascals, so 101.325 Kilopascals x 1.45 Atmospheres = 146.92125 Kilopascals.
Using the conversion table, the pressure of the compressed gas at 1.45 atm when converted to kilopascal becomes 146.92 kPa.
How to convert from atm to kPa?
Atm is the standard atmosphere which is a unit of pressure.
From conversion table
1 atm atmospheric pressure is equivalent to 101.325 kPa ( kilopascal ).
Now, the pressure of the compressed gas at 1.45 atm will be;
P = 1.45 × 101.325 kPa
P = 146.92 kPa
Therefore, the pressure of the compressed gas at 1.45 atm when converted to kilopascal using the conversion table becomes 146.92 kPa.
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Calculate ΔHrxn for the following reaction:CH4(g)+4Cl2(g)→CCl4(g)+4HCl(g)Use the following reactions and given ΔH′s.C(s)+2H2(g)→CH4(g)ΔH=−74.6kJC(s)+2Cl2(g)→CCl4(g)ΔH=−95.7kJH2(g)+Cl2(g)→2HCl(g)ΔH=−184.6kJ
Answer:
ΔH= -390.3kJ
Explanation:
Using Hess's law, we can obtain ΔHrxn from the sum of related reactions.
Using:
(1) C(s) + 2H2(g) → CH4(g) ΔH=−74.6kJ
(2) C(s) + 2Cl2(g) → CCl4(g) ΔH=−95.7kJ
(3) H2(g) + Cl2(g) → 2HCl(g) ΔH=−184.6kJ
(2) - (1):
CH4(g) + C(s) + 2Cl2(g) → CCl4(g) + C(s) + 2H2(g)
CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g)
ΔH= -95.7kJ - (-74.6kJ) = -21.1kJ
This reaction + 2*(3):
2H2(g) + 2Cl2(g) + CH4(g) + 2Cl2(g) → CCl4(g) + 2H2(g) +4HCl(g)
CH4(g) + 4Cl2(g) → CCl4(g) + 4HCl(g)
ΔH= -21.1kJ + 2*-184.6kJ
ΔH= -390.3kJWhich of the following grouping contains only representative elements?
A. Na, Co, S
B. Ni, Ga, Zn
c. AI, Mg, LÍ
D. CI, O, Cd
Answer:
C
Explanation:
Al=Aluminum
Mg=Magnesium