Answer:
helium , krypton,xenon,radon, argon are noble gasses
In each of the following groups of substances, pick the one that has the given property. Justify your answer. a) highest boiling point: HBr, Kr, Cl2 b) highest freezing point: H2O, NaCl, Hf c) lowest vapor pressure at 25C: Cl2, Br2, I2 d) lowest freezing point: N2, CO, CO2 e) lowest boiling point: CH4, CH3CH3, CH3CH2CH3 f) highest boiling point: HF, HCl, HBr Could someone help me understand fully how to do this?
Answer:
A) HBr
b) NaCl
c) I2
d) N2
e) CH4
f) HF
Explanation:
a) HBr has the highest boiling point because its molecules are held by intermolecular hydrogen bonding unlike other compounds listed.
b) the freezing point of a substance is the same as its melting point. Ionic substances have the highest melting points. Hence NaCl has a melting (freezing) point of about 801°C
c) vapour pressure depends on molecular mass. The higher the molecular mass the lower the vapour pressure. I2 has the highest relative molecular mass and hence the lowest vapour pressure.
d) The molecule with the lowest molecular mass is expected to have the lowest intermolecular dispersion forces and hence the lowest freezing point.
e) Degree of dispersion forces and boiling point increases with increase in molecular mass. Since CH4 has the lowest molecular mass, it will also possess the lowest boiling point.
e) The magnitude of electro negativity decreases down the group. Hence, fluorine is the most electronegative element among the halogens. Hydrogen bonding results when hydrogen is covalently bonded to an electronegative element. The strength of the hydrogen bonding depends on the electro negativity of the electronegative element.
For hydrogen halides, HF has the highest boiling point since F is the most electronegative halogen and HF possess the greatest degree of hydrogen bonding among the hydrogen halides. Hydrogen bonding leads to increase in boiling point of substances.
The intermolecular forces in the compound have been responsible for the various properties of the compounds.
(a) Highest boiling point:
The hydrogen bonding has resulted from the electrostatic interaction of the H with the more electronegative atom. The strong interaction results in a higher boiling point.
HBr has consisted of the hydrogen bond, thus having the highest boiling point.
(b) Highest freezing point:
The higher hydrogen bonding in the structure results in a high freezing point. The ionic compounds with electrostatic interactions result in a high freezing point.
NaCl has been an ionic compound, thus has been consisted of the highest freezing point.
(c) Lowe vapor pressure:
Vapor pressure has been inversely proportional to the molecular mass. The higher the molecular weight, the lower has been the vapor pressure.
Iodine has the highest molecular weight, thereby has the lowest vapor pressure.
(d) Lowest freezing point:
Based on the molecular weight, the lower the molecular weight, the lower has been the freezing point of the molecule.
The [tex]\rm \bold{CH_4}[/tex] has the lowest molecular weight, thus the lowest freezing point.
(e) Highest boiling point:
The more electronegative atom in the hydrogen bonding, the higher has been the stability and the higher the boiling point.
HF has the highest boiling point as it has H bonded with the most electronegative element.
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How do gases responsible for acid rain get into the atmosphere
(b) (i)
What is an ion?
(c)
Name two types of ions and state how they are formed
Types of ions:
Answer:
an atom or molecule with a net electric charge due to the loss or gain of one or more electrons
In nuclear fusion, small fragments, like atomic nuclei, neutrons, and other particles, form when energy is released. TRUE FALSE
Answer:
TRUE
Explanation:
It is true because along with energy, nuclear fusion releases other particles as well. This can include neutrons or atomic nuclei. An example of this is when hydrogen isotopes (D + T) fuse together to create helium it also releases a neutron. Thus D+T --> He + n + energy.
Therefore the answer is TRUE.
in which sphere does a dolphin swim A. hydrosphere B. atmosphere C. magnetosphere D. lithosphere
Answer:
A. Hydrosphere
Explanation:
Hydro means water and dolphins swim in water.
I hope this helps :)
You arrive home from class to find your roommate complaining of a headache, dizziness, and nausea. Upon further investigation you believe they may have carbon monoxide poisoning. What should be the first step taken?
Answer:
tempature of the person, check carbon levels in the house or place where the person is.
Explanation:
Consider the half reaction below.
Which statement best describes what is taking place?
Chlorine is losing electrons and being oxidized. Chlorine is losing electrons and being reduced. Chlorine is gaining electrons and being oxidized. Chlorine is gaining electrons and being reduced.
Answer:
balancing of charges of both sides
Answer:
A
Explanation:
A...............................
in terms of bonds what would the molecule C6H12 be classified as
It has a double C=C bond so that means it's unsaturated, but it can also be a cyclic compound with only simple C-C bonds
Alkene
I did the test
Which element would have properties most similar to those of
cesium (Cs)?
O A. Rb
B. Ca
C. Sr
D. Ba.
Answer:
Rb
Explanation:
This is because they are in the same group which means they share similar properties.
What do rubidium and cesium have in common?
This family consists of the elements lithium, sodium, potassium, rubidium, cesium, and francium (Li, Na, K, Rb, Cs, and Fr, respectively). Group one elements share common characteristics.
What are the physical and chemical properties of caesium?
It is silvery gold, soft, and ductile. It is the most electropositive and most alkaline element.
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using equation of reaction mention 4 methods of preparation of hydrogen
Explanation:
1. Displacement of hydrogen from water by using metal
2. Electrolysis of water using the apparatus known as the HOFMAN VOLTAMETER
3. Cracking of petroleum
4. Action of steam on hot coke
Calculate the pH of a solution obtained by mixing 477 mL of 0.17 M hydrochloric acid with 253 mL of M lithium hydroxide. Assume the combined volume is the sum of the two original volumes.
Answer:
pH = 0.984
Explanation:
Molarity LiOH = 2.1x10⁻²M
HCl will react with LiOH as follows:
HCl + LiOH → H₂O + LiCl
1 moles of HCl reacts per mole of LiOH
Moles of each reactant in solution are:
HCl = 0.477L ₓ (0.17mol / L) = 0.08109 moles HCl
LiOH = 0.253L ₓ (2.1x10⁻² mol / L) = 5.313x10⁻³ moles of LiOH.
That means LiOH is the limiting reactant and excess moles of HCl that will remain in solution are:
0.08109 mol - 0.005313mol = 0.0758 moles HCl
As HCl dissociates in water as H⁺ and Cl⁻ ions, you will have in solution 0.0758 moles of H⁺
pH = -log [H⁺] and [H⁺] = moles H⁺ / L of solution.
Volume of the mixture in liters is: 0.477L + 0.253L = 0.730L.
That means [H⁺] is 0.0758 moles of H⁺ / 0.730L = 0.1038M
Replacing:
pH = -log [H⁺]
pH = -log [0.1038]
pH = 0.984Answer the following questions: On a 10-fold dilution of a weak acid, the pH will ______________ . On a 10-fold dilution of a weak base, the pH will ______________. If one adds a very small amount of strong base to a buffered solution, the pH will _______________. Can you make a buffer using a strong acid
Answer:
i) increase
ii) decrease
iii) remain the same
iv) No, because it dissociates completely.
Explanation:
On a 10-fold dilution of a weak acid, the pH will increase because the concentration of hydrogen ions will decrease thereby increasing the pH to close to that of water.
On a 10-fold dilution of a weak base, the pH will decrease due to the removal of hydroxide ions from the solution. This results in the solution having a H closer to that of water.
If one adds a very small amount of strong base to a buffered solution, the pH will remain constant because a buffer solution acts to withstand any change to its pH on the addition of small quantities of either an acid or a base.
A buffer solution cannot be made with a strong acid because thy undergo complete dissociation. Therefore, any small addition of base or acid will result in very large changes in the pH of the solution. A buffer solution is made with a weak acid and its conjugate base or a weak base and its conjugate acid.
List at least four characteristics of acids
Answer:
pH>7
sour taste
donate H+ ions
turn litmus paper from blue to red
Explanation:
Answer:
Explanation:
pH < 7.
Sour taste (though you should never use this characteristic to identify an acid in the lab)
Reacts with a metal to form hydrogen gas.
Increases the H+ concentration in water.
Donates H+ ions.
Turns blue litmus indicator red.
Which is described as the force holding two atoms together? Select one: a. cation b. chemical bond c. formula unit d. lattice
Answer:
The correct option is;
b.Chemical bond
Explanation:
Chemical bonds are the attractive forces holding the atoms within a compound together. The concept of chemical bonding is fundamental to the explanation of chemical phenomena including reaction mechanism and molecular behavior
There are different chemical bonds such as ionic bonds formed by the attraction of oppositely charged ions, covalent bonds, formed by the sharing of electrons and polar covalent bonds.
Help ya girl out plz
Answer:
The correct option is B
Explanation:
just did it edg 2020.
Answer:
the answer is c
Explanation:
Design a voltaic cell using magnesium as one of the electrodes. Magnesium can be represented as either Metal A or Metal B in the above drawing. Use metal chlorides as the solutions in the two chambers. For example, magnesium chloride, (MgCl2) will be in solution in the chamber with the magnesium electrode. Use NaNO3 in the salt bridge. Select another element for the other electrode. Explain why you selected this element. Include information about the activity of the metal you select and the need for a spontaneous reaction. Metal A: Metal B: In the drawing, 1. Label the oxidation compartment: 2. Label the reduction compartment. 3. Label the direction of the flow of electrons. 4. Label the flow of the magnesium ions. 5. Label the flow of your selected element's ions. 6. What is leaving the salt bridge in the anode compartment? 7. What is leaving the salt bridge in the cathode compartment? 8. Write the oxidation and reduction half-reactions. 9. Calculate the chemical potential of your cell. Show all of your work.
Answer:
Here's what I get
Explanation:
You haven't shown your drawing, so I will assume that Metal A is the anode and Metal B is the cathode.
I will make a galvanic cell using Mg and Zn as the metals.
I selected Zn because it is common and readily available in the lab.
Zn is lower than Mg in the activity series, so Mg should be able to displace Zn from its salts
The standard reduction potentials are:
E°/V
Zn²⁺ (aq) + 2e⁻ ⇌ Zn(s); -0.76
Mg²⁺(aq) + 2e⁻ ⇌ Mg(s); -2.38
The Mg half-reaction has the more negative potential, so it will be the oxidation half-reaction.
8 and 9. Oxidation and reduction half-reactions and cell potential
E°/V
Oxidation: Mg(s) ⇌ Mg²⁺(aq) + 2e⁻ ; +2.38
Reduction: Zn²⁺ (aq) + 2e⁻ ⇌ Zn(s); -0.76
Mg(s) + Zn²⁺ (aq) ⇌ Mg²⁺(aq) + Zn(s); +1.62
The cell potential is positive, so the reaction will be spontaneous.
Mg is the anode, so it is Metal A.
Zn is the cathode, so it is Metal B.
1. The Mg|Mg²⁺ half-cell is the oxidation compartment.
2. The Zn²⁺|Zn half-cell is the reduction compartment.
3. The electrons flow from anode to cathode in the external circuit.
4. The Mg²⁺ ions flow from the Mg through the solution to the salt bridge.
5. The Zn²⁺ ions flow from the solution to the Zn.
6. NO₃⁻ ions flow from the salt bridge into the anode compartment to balance the charge of the developing Zn²⁺ ions.
7. Na⁺ ions flow from the salt bridge into the cathode compartment to replace the charge of the depleted Zn²⁺ ions.
Which type of graph is best used to show how a measured quantity changes over time?
Box and whisker plot
Line graph
Circle graph
Histogram
A π bond could be formed from the overlap of which two orbitals? A) two sp² hybrid orbitals B) a 1s and a sp² hybrid orbital C) a sp and a sp² hybrid orbitals D) two unhybridized p orbitals
Answer:
D) two unhybridized p orbitals
Explanation:
In covalent bond, to form a bond, each of the two participating atoms would put down an unpaired electron to be used in forming a shared pair of electrons between them.
There are two types of covalent bonds:
A sigma bond [tex]\sigma[/tex]
A pi bond [tex]\pi[/tex]
A sigma bond is formed when a hybrid orbital (sp,sp² and sp³) overlaps with another hybrid orbital or with s- or p- orbital.
A pi bond is formed when a p-orbital overlaps with another parallel p-orbital laterally. This implies that ,a π bond could be formed from the overlap of two unhybridized p orbitals.
In which particle model are the red and blue particles MOST LIKELY to bump into each other? PLEASE HELP WILL MARK BRAINLIEST!!
Answer:
441
Explanation:
In particle model A are the red and blue particles MOST LIKELY to bump into each other and the correct option is option A.
What is Particle Model of Matter?The particle model of matter is a theory that explains how the particles that make up a substance are arranged, and how they move and interact with each other.
The particle model explains the properties of solids, liquids and gases. The particle model can explain changes of state.
Particles of matter have spaces between them. Atoms and molecules have spaces between them. In a gas, there are large spaces between them. In a a liquid they are closer together. In a solid, the particles are packed close enough together they can hardly move.
Therefore, In particle model A are the red and blue particles MOST LIKELY to bump into each other and the correct option is option A.
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what reaction type is solid sodium bicarbonate + acetic acid?
Answer:
the neutralization reaction occurs
in terms of bonds, what would the molecule C3H6 be classified as
Explanation:
Cyclopropane is a cycloalkane conposed of three carbon atoms to form a ring. It has a rols as an inhalation anaesthetic. It is a cycloalkane and a member of cyclopropanes.
Answer:
Alkane
Explanation:
Which statement is true about oxygen-17 and oxygen-18? A Their atoms have identical masses B They do not have the same number of protons C They have different numbers of electrons D They are isotopes of oxygen
Answer:
option d
Explanation:
isotope means atoms with different mass no. 17 and 18 written on the left represent mass number
this is because atoms can differ in mass no.
option a is incorrect as they have different mass no,hence,different massoption b is incorrect as atoms-oxygen-17 and oxygen 18-of same element oxygen cannot differ in no of protonsif they had different no of electons they would have a charge like -1,-2,etcoption d is correct,because atoms can differ in mass no. isotope means atoms with different mass no. 17 and 18 written on the left represent mass numberThe graph compares the kinetic energies of the molecules in four gas samples. Each graph shows a normal distribution, so the average is the center. Which sample is likely to have the lowest temperature? (1 point) A B C D
Answer:
d
Explanation:
i got it right
Gas A is likely to have the lowest temperature. Hence, option A is correct.
What are molecules?The smallest particle of a substance has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms.
In a gas, the kinetic energy is directly proportional to the temperature under constant pressure and volume.
As you can see in the problem, the average of A has low kinetic energy. But the average is increasing between B, C and D.
As gas A has the lowest average kinetic energy:
Gas A is likely to have the lowest temperature
Hence, option A is correct.
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)Assertion: Corrosion is a beneficial process for metals. Reason : Galvanising and electroplating of metals prevent corrosion.
A current is induced in a wire by moving the wire through a magnetic field. Which is one factor that affects the direction of the current?
Answer:
One factor that affects that affects the direction of the current is the direction of motion of the wire
Explanation:
According to Fleming's right hand rule when a conductive wire which is within a circuit is moved through a magnetic field, due to Faraday's law of electromagnetic induction an electric current is induced in the wire such that the direction of motion of the wire, the direction of the magnetic field and the direction of the electric current are perpendicular to each other such that if the right hand has the thumb middle finger and the index finger held perpendicular to each other
The motion of the wire being in the direction of the wire
The first or index finger points in the direction of the magnetic field
The middle finger points in the direction of the induced electric current
Therefore, the direction of the the current depends on the direction of motion of the wire.
Which sequence represents the relationship between temperature and volume as explained by the kinetic-molecular
theory?
higher temperature - more kinetic energy - more space between particles - higher volume
higher temperature-less kinetic energy less space between particles - higher volume
higher temperature → more kinetic energy less space between particles > lower volume
higher temperature-less kinetic energy → more space between particles lower volume
3
and wit
Answer:
A.
Explanation:
Higher temperature - more kinetic energy - more space between particles - higher volume.
To change from tens to hundreds, you multply by
Answer:
10
Explanation:
Example:
10 · 10 = 100
60 · 10 = 600
Answer:
you multiply by 10.
Explanation:
10 - the one is in the thenth place
10 * 10 = 100 - the one is in the hundreth place
20 - the two is in the thenth place
20 * 10 = 200 - the two is in the hundreth place
How can the rate constant be determined from the rate law
Answer: The rate constant is the reaction rate divided by the concentration terms.
What is the concentration of a solution if 65 g of sugar is dissolved into 200 ml of water?
Answer: the concentration in g/L 325 while in molarity is 0.6398(M).
Answer:
325 g/L,
0.9503 M
Explanation:
65 g sugar --- 0.2 L
x g --- 1 L
x = 65/0.2 g/L = 325 g/L
Sugar(sucrose) is C12H22O11.
Molar mass (C12H22O11) = 12*12 + 1*22 + 16*11 = 342 g/mol
325 g/L * 1 mol/342 g = 0.9503 mol/L = 0.9503 M
Answer 0.6398(M) is not related to sugar (sucrose),
it should be given formula or molar mass of sugar if it is different than sucrose.
Given 16.2 grams of substance Y, if the substance absorbs 2722 joules of energy and the specific heat of the substance is 9.22 J/g·°C, what is the final temperature of the substance if the initial was 26 degrees Celsius?
Answer:
Final temperature (T) = 44.22°C (Approx)
Explanation:
Given:
Mass of Y (m) = 16.2 gram
Energy required (q) = 2722 J
Specific heat of the substance(c) = 9.22 J/g·°C
Change in temperature ΔT = T - 26°C
Find:
Final temperature (T)
Computation:
q = mcΔT
2722 = (16.2)(9.22)(T - 26°C)
18.224 = T - 26°C
T = 26 + 18.224
T = 44.224°C
Final temperature (T) = 44.22°C (Approx)