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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What shape is represented by three bound groups and one lone pair around a
central atom?
A. Bent
B. Tetrahedral
C. Linear
D. Trigonal pyramidal
Answer:
D Trigonal pyramidal
Explanation went over in class:
Answer:
D. Trigonal pyramidal
Explanation:
A P E X !
1) Determine a fórmula da base hidróxido de bário: * 1 ponto a) b) c) d) 2) As bases são substâncias iônicas, ou seja, quando são solubilizadas em água liberam íons, qual das características abaixo pode ser atribuída as soluções iônicas? * 1 ponto a) Conduzem corrente elétrica. B) Isolantes elétricos. C) Radioatividade. D) Emissão de raio UVA.
Answer:
1) Ba(OH)₂
2) The correct option is a) they conduct electricity.
Explanation:
To deduce the formula of Barium hydroxide, we have to go to the periodic table and look for the Barium (Ba), which is in group 2 and has an ionic charge of 2+. Hydroxides are not an element that is present in the periodic table is the combination of Oxygen and Hydrogen (OH), and its ionic charge is 1-.
To name this substance, we write the elements that form it, which are Ba OH, then we see the ionic charges that they have, Ba2+ OH 1- and we change these charges giving the 2+ to the OH and the 1- to the Ba. It would look Ba OH₂; we do not write the 1, and as there is a 2, the OH, has to be between brackets so that the final formula is Ba(OH)₂. What we did is balancing the charges of the elements. In other words, we need 2 OH for every Ba. Hydroxides give an electron to balance the Ba ionic charge.
Barium Hydroxide is an ionic compound because ionic compounds are formed by a metal (Ba) and a nonmetal element (OH), ionic compounds are charged, so when they are in an aqueous solution they conduct electricity because their ions move freely in the solution.
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.
A sample of O2 gas is collected over water at 25oC at a barometric pressure of 751 torr. The vapor pressure of water at 25oC is 23.8 torr. What is the partial pressure of the O2 gas in the sample
Answer:
727.7 torr
Explanation:
Since the gas was collected over water, it is likely to be saturated with water vapour and the total pressure is given as;
Ptotal = Pgas + Pwater
From the question;
Ptotal = 751 torr
Pgas = ?
Pwater = 23.8 torr
Making Pgas subject of equation, we have;
Pgas = Ptotal - Pwater
Pgas = 751 torr - 23.8 torr
Pgas = 727.7 torr
Potassium hydrogen tartrate is an acid used in making cookies such as snicker doodles. (In your home, it is called cream of tartar.) It can be titrated with a base such as KOH to determine purity. A sample of 0.500 g is titrated to a pink endpoint with 21.58 mL of 0.1125 M KOH. Determine the percentage of potassium hydrogen tartrate (KHC4H4O6) in the sample. The acid/base ratio is 1:1.
Answer:
91.4%
Explanation:
Potassium hydrogen tartrate, KHT, reacts with KOH as follows.
KHT + KOH → H₂O + K₂T
where 1 mole of acid (KHT) reacts per mole o base (KOH), -That is acid/base ratio 1:1
The endpoint of a titration is the point in which moles of KOH = moles of KHT, you can see this endpoint with an indicator or doing a potentiometric titration.
As the endpoint requires 21.58mL = 0.02158L of a 0.1125M KOH, moles of KOH = moles of KHT are:
0.02158L × (0.1125mol / L) = 2.428x10⁻³ moles of KOH = moles of KHT
To convert these moles to grams you use molar mass of KHT (188.177g/mol):
2.428x10⁻³ moles of KHT × (188.177g / mol) = 0.457g of KHT are in the sample.
As you add 0.500g of sample, percentage of KHT in the sample is:
(0.457g / 0.500g) × 100 =
91.4%-That is the purity of the sample-
How many valence electrons do the alkaline earth metals have?
O A. 6
O B. 2
O C. 4
O D. 8
Answer:
[tex]\boxed{2}[/tex]
Explanation:
Alkaline earth metals are in group 2. The number of valence electrons of elements in group 2 is 2.
2 valence electrons do the alkaline earth metals have. Therefore, option B is correct.
Alkaline earth metals are the elements in Group 2 of the periodic table, which includes beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra).
In general, elements in Group 2 have two valence electrons. Valence electrons are the electrons located in the outermost energy level (or shell) of an atom. For the alkaline earth metals, the outermost energy level is the second energy level, which can hold up to 8 electrons.
Only the two electrons in the s sublevel of the second energy level are considered valence electrons. These two valence electrons are involved in chemical reactions and bonding.
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Consider the hydrocarbon below. 2 carbons are double-bonded to each other; the pair are single bonded to H above left, above right, below right, and below left. What is the name of this hydrocarbon?
Answer:
Ethene.
Explanation:
To know the name of the compound given above, we must:
1. Determine the number of carbon present in the compound.
2. Determine whether a single, double or triple is present in the compound.
3. Combine the above to get the name.
Now, let us name compound given above. This is illustrated below:
1. The compound contains two (2) carbon atom.
2. The compound contains a double bond. Therefore, the compound is an alkene.
3. An alkene with two carbon atoms is called ethene.
Therefore, the name of the compound given in the question is called ethene.
Answer:
other guy is right :)
Explanation:
if you look up "ethene hydrocarbon" online, the image attached in the question pops up!
)Assertion: Corrosion is a beneficial process for metals. Reason : Galvanising and electroplating of metals prevent corrosion.
HELPSS!
Isopropyl alcohol has a density of 0.785g/ml at 25°C. How much is contained in a 150ml sample of this alcohol?
Answer:
The amount of isopropyl alcohol contained in 150 ml of the solution is 117.15 grams
Explanation:
The density of a substance is the mass per unit volume, therefore, we have;
The density of the isopropyl alcohol = 0.785 g/ml at 25°C
The density = mass/volume
Mass = Density × Volume
The mass of the 150 ml of isopropyl alcohol is therefore;
Mass = 0.785 g/ml × 150 ml = 117.15 g
The amount in grams contained in 150 ml of sample = 117.15 g.
2g of magnesium Oreo to excess dilute acid according to the equation Mg(s) + 2H (aq) --- Mg² (aq) + H2 (g) (Realitive atomic mass of Mg= 24, molar mass volume at room temperature and pressure = 24dm³) The volume of hydrogen, measured at room temperature I pressure, that is produced is A) 1000 cm³ B)1500 cm³ C) 2000 ³cm D) 24 000 cm³
Answer:
Option C. 2000 cm³.
Explanation:
We'll begin by calculating the number of mole in 2 g of Mg. This is illustrated below:
Molar mass of Mg = 24 g/mol
Mass of Mg = 2 g
Mole of Mg =?
Mole = mass /Molar mass
Mole of Mg = 2/24
Mole of Mg = 8.33×10¯² mole.
Next, we shall determine the number of mole of H2 produced from the reaction. This is illustrated below:
Mg(s) + 2H^+ (aq) —› Mg^2+(aq) + H2 (g)
From the balanced equation above,
1 mole of Mg reacted to produce 1 mole of H2.
Therefore, 8.33×10¯² mole of Mg will also produce 8.33×10¯² mole of H2.
Finally, we shall determine the volume of H2 produced. This is illustrated below:
1 mole of H2 occupy 24000 cm³ at room temperature and pressure.
Therefore, 8.33×10¯² mole of H2 will occupy = 8.33×10¯² x 24000 ≈ 2000 cm³ at room temperature and pressure.
Therefore, 2000 cm³ of H2 were obtained from the reaction.
Which of these is an ex
example of a composite material?
Answer:
A composite material is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components.
Explanation:
you're welcome
Ethylene, a gas found in nature, is commonly used to ripen bananas and other fruits. Which compound is ethylene?
H2C — CH2
НО
НО
Н
Н
0
С — С
Н
Н
ОН — СЕ С — Н
Answer:
C2H4
Explanation:
cause the compound of ethylene is C2H4
Ethylene is a hydrocarbon gas with the chemical formula C₂H₄. It is a simple molecule that consists of two carbon atoms and four hydrogen atoms and is also known as ethene. The skeletal structure is CH₂=CH₂.
What is ethylene ?Ethylene is a colorless and odorless gas that is the simplest member of the olefin class of hydrocarbons, with the chemical formula C₂H₄. It is an important organic compound and is widely used in industry.
Ethylene is primarily used to produce polyethylene, which is one of the most common plastic materials in the world. It is also used as a fuel in some industrial processes, as a refrigerant, and as a precursor to other chemicals.
It is an important plant hormone and is involved in various physiological processes such as fruit ripening, senescence, and abscission. Ethylene is naturally produced by plants, but it can also be produced artificially and is commonly used in agriculture to ripen fruits and vegetables.
Thus, the ethylene compound is CH₂=CH₂.
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The steady state vital to life is possible because:________
a. the cell cannot convert energy from one form to another.
b. all cells are autotrophic.
c. all reactions are exothermic.
d. the cell continually takes up energy from the environment.
e. all reactions are at equilibrium.
Answer: The correct answer is e) all reactions are at equilibrium.
Explanation: In order for cellular vitality to develop, it is necessary for it to be in energetic balance with the environment, that is, to give and receive energy with the environment that surrounds it through endothermic or exothermic reactions. That is why the development of life is considered a system that constantly exchanges with the environment. In turn, that the cell unit maintains a balance with the environment causes homeostasis to occur among the whole organism.
Which action destroys topsoil?
Answer:
I think it erosion
Explanation:
Well erosion washes away top soil
HELP ME ASAP PLISSSSS
Answer:
In this titration, solution P (that contains hydrochloric acid) is added into the conical flask that contains sodium hydroxide drop by drop. The indicator (phenolphthalein) changes color when all the NaOH is completely neutralized.
i) Solution P contains hydrochloric acid. Hydrochloric acid is the chemical that reacts with sodium hydroxide to give salt and water.
This type of reaction is called neutralization.
ii) Under alkaline conditions, phenolphthalein appears pink in color. When the solution becomes neutral or acidic, it is colorless.
So, the color change of the mixture at the end point is from pink to colorless.
iii) same explanation from question i,
HCl (aq) + NaOH (aq) --> NaCl (aq) + H2O (l)
iv) no. of moles = volume (in dm3) x concentration
hence,
no. of moles of NaOH used = 25/1000 x 0.1
= 0.0025 mol
From the equation in (iii), since the mole ratio of HCl : NaOH = 1:1, meaning 1 mole of HCl reacts completely with 1 mole of NaOH.
This also means that the no. of moles of NaOH reacted equals to the no. of moles of HCl needed to react with it, which is 0.0025 mol.
Given the concentration of HCl in solution P is 0.1 mol /dm3. (pls correct me if I misunderstood your comment),
if v is the volume of HCl needed,
0.0025 = 0.1 v
v = 0.025 dm3
also = 25 cm3
Answer:
In this titration, solution P (that contains hydrochloric acid) is added into the conical flask that contains sodium hydroxide drop by drop. The indicator (phenolphthalein) changes color when all the NaOH is completely neutralized.
i) Solution P contains hydrochloric acid. Hydrochloric acid is the chemical that reacts with sodium hydroxide to give salt and water.
This type of reaction is called neutralization.
ii) Under alkaline conditions, phenolphthalein appears pink in color. When the solution becomes neutral or acidic, it is colorless.
So, the color change of the mixture at the end point is from pink to colorless.
Explanation:
what kind of a compounds act as an electrolyte? explain with and example
Answer:
ionic compounds
Explanation:
just finished ap chem
Answer:
An ionic compound can act as an electrolyte. This is because an electrolyte should allow charges to travel inside it.
e.g = H2SO4, NaCl
Explanation:
If a had a number that was 12.47, what would be the answer rounded to 2 sig figs?
12
Explanation:
Look at the number directly after the number you want to keep. I'm your case you want to keep the first two numbers and the number directly after is 4 so there is no need to round up. Keep your 12 without a decimal.
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.
What is the precipitate in the following reaction?
2AgNO3(aq) + Na2S(aq) → Ag2S(s) + 2NaNO3(aq)
Answer:
2Ag(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(aq)
Explanation:
The final equation is
2Ag(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(aq)
2Ag(+1)NO3(-1)(aq) + Na2(+1)S(-2)(aq) --> Ag2(+1)S(-2)(s) + 2Na(+1)NO3(-1)(aq)
AgNO3, Na2S, and NaNO3 are all strong electrolytes, so we immediately separate those, making the new equation:
2Ag(+1)(aq) + 2NO3(-1)(aq) + 2Na(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(s) + 2Na(+1)(aq) + 2NO3(-1)(aq)
After that, you cancel out all the ions that appear more than once, which in this case would leave us with a final equation of...
2Ag(+1)(aq) + S(-2)(aq) --> Ag2(+1)S(-2)(aq)
Answer:
Explanation:
C
How many atoms are in 10g of Al
Answer:
The correct answer is
Explanation:
hope this helps u!!
Name the layer where the pressure is 3.5 million atmospheres:
Answer:
The Inner Core
hope it was useful
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........
according to Bohr atomic model
Answer:
A small positively charged nucleus surrounded by revolving negatively charged electrons in fixed orbits
This law relates a planet's orbital period and its average distance to the Sun.
The orbits of planets are ellipses with the Sun at one focus.
The speed of a planet varies, such that a planet sweeps out an equal area in equal time frames.
Answer:
These are Kepler's Laws of Planetary Motion
Explanation:
Answer:
its Keplers third law,
then first law,
then second law
Explanation:
Which of these elements have the smallest 1st ionization energy
Answer:
Ionization energy increases as you go across a period, and increases as you move up a group. So, elements with the smallest ionization energy would be at the bottom left corner of the periodic table. Examples of elements with small ionization energy: Francium (Fr), Cesium (Cs), Radium (Ra).
D Serum Levels Of 4 Mcg/mL, Calculate The Dose, In Milligrams, For A 120-lb Patient That May Be Expected To Result In A Blood Serum Gentamicin Level Of 4.5 Mcg/mL. This problem has been solved! See the answer If the administration of gentamicin at a dose of 1.75 mg/kg is determined to result in peak blood serum levels of 4 mcg/mL, calculate the dose, in milligrams, for a 120-lb patient that may be expected to result in a blood serum gentamicin level of 4.5 mcg/mL.
Answer:
The patient requires a dose of 107.2 mg of gentamicin
Explanation:
A dosage of 1.75 mg per Kilogram body weight results in blood serum levels of 4.5 mcg/mL
This means that; 1.75 mg/ kg = 4.0 mcg/mL
Therefore, dosage of gentamicin in mg/kg that will result in 4.5 mcg/mL blood serum level = (1.75 mg/Kg * 4.5 mcg/mL) / 4.0 mcg/mL
Dosageof gentamicin = 1.97 mg/Kg
1-lb = 0.453592 Kg
Weight of 120-lb patient in Kg = 120 * 0.453592 = 54.43 Kg
Dose in mg required by patient = 1.97 mg/Kg * 54.43 Kg = 107.2 mg
Therefore, the 120-lb patient requires a dose of 107.2 mg of gentamicin to result in a blood serum level of 4.5 mcg/mL
A 36.0−g sample of an unknown metal at 99°C was placed in a constant-pressure calorimeter containing 70.0 g of water at 24.0°C. The final temperature of the system was found to be 28.4°C. Calculate the specific heat of the metal. (The heat capacity of the calorimeter is 12.4 J/°C.)
Answer: 0.52849 j /g °C
Explanation:
Given the following :
Mass of metal = 36g
Δ Temperature of metal = (28.4 - 99)°C = - 70.6°C
Mass of water = 70g
Δ in temperature of water = (28.4 - 24.0) = 4.4°C
Heat lost by metal = (heat gained by water + heat gained by calorimeter)
Quantity of heat(q) = mcΔT
Where; m = mass of object ; c = specific heat capacity of object
Heat lost by metal:
- (36 × c × - 70.6) = 2541.6c - - - - (1)
Heta gained by water and calorimeter :
(70 × 4.184 × 4.4) + (12.4 × 4.4) = 1288.672 + 54.56 = 1343.232 - - - - (2)
Equating (1) and (2)
2541.6c = 1343.232
c = 1343.232 / 2541.6
c = 0.52849 j /g °C
What is the total energy change for the following reaction:CO+H2O-CO2+H2
Answer:
[tex]\large \boxed{\text{-41.2 kJ/mol}}[/tex]
Explanation:
Balanced equation: CO(g) + H₂O(g) ⟶ CO₂(g) + H₂(g)
We can calculate the enthalpy change of a reaction by using the enthalpies of formation of reactants and products
[tex]\Delta_{\text{rxn}}H^{\circ} = \sum \left( \Delta_{\text{f}} H^{\circ} \text{products}\right) - \sum \left (\Delta_{\text{f}}H^{\circ} \text{reactants} \right)[/tex]
(a) Enthalpies of formation of reactants and products
[tex]\begin{array}{cc}\textbf{Substance} & \textbf{$\Delta_{\text{f}}$H/(kJ/mol}) \\\text{CO(g)} & -110.5 \\\text{H$_{2}$O} & -241.8\\\text{CO$_{2}$(g)} & -393.5 \\\text{H$_{2}$(g)} & 0 \\\end{array}[/tex]
(b) Total enthalpies of reactants and products
[tex]\begin{array}{ccr}\textbf{Substance} & \textbf{Contribution)/(kJ/mol})&\textbf{Sum} \\\text{CO(g)} & -110.5& -110.5 \\\text{H$_{2}$O(g)} &-241.8& -241.8\\\textbf{Total}&\textbf{for reactants} &\mathbf{ -352.3}\\&&\\\text{CO}_{2}(g) & -393.5&-393.5 \\\text{H}_{2} & 0 & 0\\\textbf{Total}&\textbf{for products} & \mathbf{-393.5}\end{array}[/tex]
(c) Enthalpy of reaction [tex]\Delta_{\text{rxn}}H^{\circ} = \sum \left( \Delta_{\text{f}} H^{\circ} \text{products}\right) - \sum \left (\Delta_{\text{f}}H^{\circ} \text{reactants} \right)= \text{-393.5 kJ/mol - (-352.3 kJ/mol}\\= \text{-393.5 kJ/mol + 352.3 kJ/mol} = \textbf{-41.2 kJ/mol}\\ \text{The total enthalpy change is $\large \boxed{\textbf{-41.2 kJ/mol}}$}[/tex]
How fast do sound waves travel under normal conditions? A. 110 feet each second B. 1100 miles per hour C. 1100 feet each second D. 1100 miles each second
Answer:
110 feet each second......
I think
Answer:
110 hope its right
Explanation:
How science classified?
any additional answer please thanks
Answer:
Scientific Classification. Classification, or taxonomy, is a system of categorizing living things. There are seven divisions in the system: (1) Kingdom; (2) Phylum or Division; (3) Class; (4) Order; (5) Family; (6) Genus; (7) Species. ... Species are identified by two names (binomial nomenclature)
Explanation:
Question 18 of 25
How is the atomic number related to core electrons?
O A. The atomic number is equal to the number of core electrons.
O B. The atomic number minus the period number is the number of
core electrons.
O C. The atomic number plus the group number is the number of core
electrons.
O D. The number of valence electrons plus core electrons is the atomic
number
Answer:
D
Explanation:
If the atom is neutral, the sum of the core and valence electrons is the same as the number of protons, which is the atomic number of the element. So if the sum of the core and valence electrons in a neutral atom equals 25 , that is the number of protons in the atomic nucleus, and the atomic number of the element.
The number of valence electrons plus core electrons is the atomic number.
How is the atomic number related to the variety of electrons?The variety of protons, neutrons, and electrons in an atom may be determined from a set of easy guidelines. The wide variety of protons within the nucleus of the atom is equal to the atomic quantity (Z). The quantity of electrons in an impartial atom is identical to the number of protons.
What's an atomic number associated with?The variety of protons in a nucleus is called the atomic variety and usually equals the number of electrons in orbit approximately that nucleus (in a nonionized atom). For this reason, all atoms which have an equally wide variety of protons and the atomic range are atoms of the equal element.
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