Answer:
A molecule is the answer.
The IE1, for iodine, is 1009 kJ/mol. Calculate the wavelength (in nm) of electromagnetic energy need to ionize an iodine atom. 118.6 743.2 488.3 1042
Answer:
118.6nm
Explanation:
It is possible to calculate wavelength of any energetic process (As an ionization) using:
E = hc / λ (1)
Where E is Energy, h is Planck constant (6.626x10⁻³⁴Js), c speed of light (3x10⁸ms⁻¹) and λ is wavelength In meters.
As the energy to ionize 1 mole of iodine is 1009kJ, one atom requires:
(1009kJ / mol) ₓ (1mol / 6.022x10²³ atoms) = 1.6755x10⁻²¹kJ / atom. = 1.6755x10⁻¹⁸J
Replacing in (1):
λ = hc / E
λ = 6.626x10⁻³⁴Js*3x10⁸ms⁻¹ / 1.6755x10⁻¹⁸J
λ = 1.186x10⁻⁷m
As 1m = 1x10⁹nm:
1.186x10⁻⁷m ₓ (1x10⁹nm / 1m) =
118.6nmA piece of silver with a mass 368 g has a heat capacity of 87.2 J/°C. What is the specific heat of
silver?
A. 0.385 J/g.°C
B. 0.237 J/g.°C
C. 0.184 J/g.°C
D. 1.322 J/g.°C
E. 4.184 J/g.°C
Answer:
B
Explanation:
Heat capacity = mass x specific heat capacity.
(C = mc)
87.2 = 368 x c
= 0.237 J/g.°C
How many hours does it take to form 15.0 L of O₂ measured at 750 torr and 30°C from water by passing 3.55 A of current through an electrolytic cell?
Answer:
The correct answer is 17.845 hours.
Explanation:
To solve the question, that is, to determine the hours required there is a need to combine the Faraday's law of electrolysis with the Ideal gas law.
Based on Faraday's law, m = Mit/nF
Here m is the mass in grams, M is the molecular mass, i is the current in amperes, t is time, n is the number of moles of electron per mole of oxygen formed and F is the Faraday's constant (the value of F is 96487 coulombs/mole).
From the above mentioned equation,
t = mnF/Mi ------(i)
Now based on ideal gas law's, PV = nRT or PV = m/M RT, here n = mass/molecular mass.
So, from the above gas law's equation, m = PVM/RT
Now putting the values of m in the equation (i) we get,
t = PVMnF/MiRT = PVnF/iRT
Based on the given information, the value of P is 750 torr or 750/760 atm = 0.98 atm, the value of v is 15.0 L, T is 30 degree C or 273 + 30 K = 303 K, i is 3.55 Amperes, and the value of R is 0.0821 atm L/mol K.
1 mole of oxygen gives 2 moles of electrons, therefore, 2 moles of oxygen will give 4 moles of electrons.
Now putting the values we get,
t = PVnF/iRT
= 0.98 atm × 15.0 L × 4 moles of electron × 96487 coulombs per mole / 3.55 coulomb per sec × 0.0821 atm L per mole-K × 303 K
= 64243.81 secs or 64243.81/3600 hr
= 17.845 hours
Calcium carbide, CaC2, reacts with water to form calcium hydroxide and the flammable gas ethyne (acetylene) in the reaction: What mass of ethyne can be produced
Answer:
1 mole of CaC₂ will produce 26g of C₂H₂ or 64.1g of CaC₂ will produce 26g of C₂H₂
Explanation:
Hello,
To solve this question, we'll require a balanced chemical equation of reaction between calcium carbide and water.
Equation of reaction
CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂
Molar mass of calcium carbide (CaC₂) = 64.1g/mol
Molar mass of water (H₂O) = 18g/mol
Molar mass of calcium hydroxide (Ca(OH)₂) = 74g/mol
Molar mass of ethyne (C₂H₂) = 26g/mol
From the equation of reaction, 1 mole of CaC₂ will produce 1 mole of C₂H₂
1 mole of CaC₂ = mass / molar mass
Mass = 1 × 64.1
Mass = 64.1g
1 mole of C₂H₂ = mass / molar mass
Mass = 1 × 26
Mass = 26g
Therefore, 1 mole of CaC₂ will produce 26g of C₂H₂
Note: this is a hypothetical calculation since we were not given the initial mass of CaC₂ that starts the reaction
2. A student has a centrifuge tube containing 14.0 g of t-butanol and is asked to make a 1.2 m solution of ethanol/t-butanol. How much ethanol would the student need to add in mL and in g? Show your calculations. Show your calculations. (6 pts)
Answer:
0.774g of ethanol
0.970mL of ethanol
Explanation:
Molality is an unit of concentration defined as the ratio between moles of solute and kg of solvent.
In the problem, you need to prepare a 1.2m solution of ethanol (Solute) in t-butanol (solvent).
14.0g of butanol are 0.014kg and as you want to prepare the 1.2m solution, you need to add:
0.014kg × (1.2moles / kg) = 0.0168 moles of solute = Moles of ethanol
To convert moles of ethanol to mass you require molar mass (Molar mass ethanol, C₂H₅OH = 46.07g/mol). Thus, mass of 0.0168 moles are:
0.0168moles Ethanol ₓ (46.07g / mol) =
0.774g of ethanolAnd to convert mass in g to mL you require density of the substance (Density of ethanol = 0.798g/mL):
0.774g ₓ (1mL / 0.798g) =
0.970mL of ehtanol
A client with a long history of cigarette smoking and poorly controlled hypertension is
experiencing psychomotor deficits due to hemorrhagic brain damage. Which diagnosis is likely
for the onset of progressive dementia?
Answer:
It may be a hemorrhagic stroke because of the patient's history.
Explanation:
Uncontrolled hypertension could generate a hemorrhagic stroke within the brain generating the sign of progressive dementia, this is due to the vessel breaking due to the excess pressure of the internal light, it breaks and releases or extravases all the bloody contents to the brain
The difficulty of this is that the brain is the one that yields to a force in relation to the skull, that is why it is compressible against hemorrhage generating these signs as progressive dementia and could even be death or vegetative state
Calculate the work (kJ) done during a reaction in which the internal volume expands from 28 L to 51 L against an outside pressure of 4.9 atm.
Answer:
W= -11KJ
Explanation:
Given:
volume expands from 28 L to 51 L
pressure =4.9 atm.
We will need to Convert the pressure to Pascal SI
But 1 atm = 101,325 Pa.
Then,
Pressure= (4.9*101323)/1atm = 5*10^5 pa
Then we need to Convert the volumes to cubic meters
But we know that1 m³ = 1,000 L.
V1= 28L * 1m^3/1000L = 0.028m^3
V2=51L × 1m^3 /1000L =0.051m^3
The work done during the expansion of a gas can be calculated as
W= -P(V2-V1)
W= - 5*10^5(0.051m^3 - 0.028m^3)
W= -1.1× 10^4J
Then we can Convert the work to kiloJoule
But1 kJ = 1,000 J.
W= -1.1× 10^4J× 1kj/1000J
= -11KJ
g A microwave oven heats by radiating food with microwave radiation, which is absorbed by the food and converted to heat. If the radiation wavelength is 12.5 cm, how many photons of this radiation would be required to heat a container with 0.250 L of water from a temperature of 20.0oC to a temperature of 99oC
Answer:
The total photons required = 5.19 × 10²⁸ photons
Explanation:
Given that:
the radiation wavelength λ= 12.5 cm = 0.125 m
Volume of the container = 0.250 L = 250 mL
The density of water = 1 g/mL
Density = mass /volume
Mass = Volume × Density
Thus; the mass of the water = 250 mL × 1 g/mL
the mass of the water = 250 g
the specific heat of water s = 4.18 J/g° C
the initial temperature [tex]T_1[/tex] = 20.0° C
the final temperature [tex]T_2[/tex] = 99° C
Change in temperature [tex]\Delta T[/tex] = (99-20)° C = 79 ° C
The heat q absorbed during the process = ms [tex]\Delta T[/tex]
The heat q absorbed during the process = 250 g × 4.18 J/g° C × 79° C
The heat q absorbed during the process = 82555 J
The energy of a photon can be represented by the equation :
= hc/λ
where;
h = planck's constant = [tex]6.626 \times 10^{-34} \ J.s[/tex]
c = velocity of light = [tex]3.0 \times 10^8 \ m/s[/tex]
= [tex]\dfrac{6.626 \times 10^{-34} \times 3.0 \times 10^8}{0.125}[/tex]
= [tex]1.59024 \times 10^{-24}[/tex] J
The total photons required = Total heat energy/ Energy of a photon
The total photons required = [tex]\dfrac{82555 J}{1.59024 \times 10^{-24}J}[/tex]
The total photons required = 5.19 × 10²⁸ photons
help please !!!!!!!!
Answer:
Option B. 2096.1 K
Explanation:
Data obtained from the question include the following:
Enthalpy (H) = +1287 kJmol¯¹ = +1287000 Jmol¯¹
Entropy (S) = +614 JK¯¹mol¯¹
Temperature (T) =.?
Entropy is related to enthalphy and temperature by the following equation:
Change in entropy (ΔS) = change in enthalphy (ΔH) / Temperature (T)
ΔS = ΔH / T
With the above formula, we can obtain the temperature at which the reaction will be feasible as follow:
ΔS = ΔH / T
614 = 1287000/ T
Cross multiply
614 x T = 1287000
Divide both side by 614
T = 1287000/614
T = 2096.1 K
Therefore, the temperature at which the reaction will be feasible is 2096.1 K
The dry- and wet-bulb temperatures of atmospheric air at 95 kPa are 25 and 178C, respectively. Determine (a) the specific humidity, (b) the relative humidity, and (c) the enthalpy of the air, in kJ/kg dry air.
A) The specific humidity of the air with the given parameters is;
w1 = 0.00967
B) The relative humidity of the air with the given parameters is;
Φ1 = 0.459
C) The enthalpy of the air in KJ/kg dry air with the given parameters is;
h1 = 49.75 KJ/Kg
Correct question is;
The dry- and wet-bulb temperatures of atmospheric air at 95 kPa are 25 and 17 °C, respectively. Determine (a) the specific humidity, (b) the relative humidity, and (c) the enthalpy of the air, in kJ/kg dry air.
We are given;
Atmospheric Pressure;P = 95 KPa
Dry temperature;T1 = 25 °C
Wet temperature;T2 = 17°C
A) From table A-4 attached and at temperature of 17°C and by interpolation, we have a saturation pressure of P_g2 = 1.938 kpa
First of all, we will calculate the specific humidity from the given pressure and saturation pressure with the formula;
w2 = (0.622 × P_g2)/(P - P_g2)
w2 = (0.622 × 1.938)/(95 - 1.938)
w2 = 0.013
Now, let's calculate specific humidity with the enthalpies at 17 °C and by interpolation. We have specific enthalpies from table A-4 as;
h_fg2 = 2460 KJ/Kg
h_g1 = 2546.5 KJ/Kg
h_f2 = 71.36 KJ/Kg
The formula for the specific humidity under these conditions is;
w1 = (c_p(T2 - T1) + w2•h_fg2)/(h_g1 - h_f2)
c_p of air has a value of 1.005 KJ/Kg.°C
Thus;
w1 = (1.005(17 - 25) + 0.013*2460)/(2546.5 - 71.36)
w1 = 0.00967
B) The relative humidity is determined from the equation;
Φ1 = (w1*p)/(0.622 + w1)p_g1
From table A-4 attached and at temperature of 25 °C, we have a saturation pressure of P_g1 = 3.1698 KPa
Φ1 = (0.00967*95)/(0.622 + 0.00967)3.1698
Φ1 = 0.459
C) For the enthalpy of air, h1 we will use the formula;
h1 = (c_p × T1) + (w1 × h_g1)
h1 = (1.005 × 25) + (0.00967 × 2546.5)
h1 = 49.75 KJ/Kg
Read more at; https://brainly.com/question/13826648
Recall that when a reaction is at equilibrium, the forward and reverse reactions occur at the same rate. To illustrate this idea, consider the reaction of A (small, red spheres) and B (large, blue spheres) to form AB.
A+B ⇌ AB
Notice that the reaction never stops. Even after several minutes, there is A and B left unreacted, and the forward and reverse reactions continue to occur. Also note that amounts of each species (i.e., their concentrations) stay the same.
Required:
What is the value of the equilibrium constant for this reaction?
Assume each atom or molecule represents a 1 M concentration of that substance.
Answer:
Equilibrium constant Kc = [x]² / [A - x] [B - x]
Explanation:
The equilibrium constant is defined as the ratio of the concentration of the products to that of the reactants at equilibrium
ie Kc = [products] / [reactants].
The balanced equation of the reaction is given as : A + B ⇄ AB
At the beginning of the reaction,
Initial concentration I = A = 1M
B = 1M
AB = 0M
After a period of time and assuming 'x' to be the concentration of product AB formed, the concentrations become
C = reactant A = [A - x] M
rectant B = [B - x] M
Product AB = [x] [x] M
At equilibrium, the concentrations are,
E = rectant A = [A - x] M
reactant B = [B - x] M
product AB = [x]² M
therefore , the equilibrium constant, Kc = [products]/[reactants]
= [x]² / [A - x] [B - x]
What volume of a 2.25 M sodium chloride solution will contain 4.58 moles of sodium chloride
(NaCl)?
A. 0.252 L
B. 119 L
C. 5.62 L
D. 0.491 L
E. 2.04 L
Answer:
Option E. 2.04 L
Explanation:
Data obtained from the question include:
Molarity of NaCl = 2.25 M
Mole of NaCl = 4.58 moles
Volume =..?
Molarity is simply defined as the mole of solute per unit litre of the solution. It is represented mathematically as:
Molarity = mole /Volume
With the above formula, we can obtain the volume of the solution as follow:
Molarity = mole /Volume
2.25 = 4.58/volume
Cross multiply
2.25 x volume = 4.58
Divide both side by 2.25
Volume = 4.58/2.25
Volume = 2.04 L
Therefore, the volume of the solution is 2.04 L
If 0.98 g of an unknown was dissolved in 10.30 g of solvent and the resulting solution has a molality of 0.45 m, what is the molar mass of the unknown
Answer:
211.4g/mol.
Explanation:
Data obtained from the question includes:
Mass of unknown compound = 0.98g
Mass of solvent = 10.30g
Molality = 0.45 M
Next, we shall determine the number of mole of the unknown compound present in the solution.
This can be obtained as follow:
Molality = mole /kg of solvent
Mole of the unknown compound =.?
Mass of solvent = 10.30g = 10.30/1000 = 0.0103Kg
Molality = 0.45 M
Molality = mole /kg of solvent
0.45 = mole /0.0103
Cross multiply
Mole = 0.45 x 0.0103
Mole = 4.635×10¯³ mole
Therefore the mole of the unknown compound that dissolve in solution is 4.635×10¯³ mole
Now, we can obtain the molar mass of the unknown compound as follow:
Mole of the unknown compound = 4.635×10¯³ mole
Mass of unknown compound = 0.98g
Molar mass of the unknown compound =?
Mole = mass /Molar mass
4.635×10¯³ = 0.98 /Molar mass
Cross multiply
4.635×10¯³ x molar mass = 0.98
Divide both side by 4.635×10¯³
Molar mass = 0.98 / 4.635×10¯³
Molar mass = 211.4g/mol.
Therefore, the molar mass of the unknown compound is 211.4g/mol.
The molecular mass of the unknown has been 211.66 g/mol.
Molality can be defined as the moles of the solute per kg of solvent.
Molality can be expressed as:
Molality = [tex]\rm \dfrac{Mass\;of\;solute\;(g)}{molecular\;mass\;of\;solute}\;\times\;\dfrac{1000}{Mass\;of\;solvent\;(g)}[/tex] ......(i)
The given unknown has been the solute.
The mass of solute = 0.98 g.
The mass of solvent = 10.30 g.
The molality of the solution formed has been = 0.45 m.
Substituting the values in equation (i):
0.45 m = [tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}\;\times\;\dfrac{1000}{10.30\;g}[/tex]
0.45 m = [tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}\;\times\;97.087[/tex]
[tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}[/tex] = [tex]\rm \dfrac{0.45}{97.087}[/tex]
[tex]\rm \dfrac{0.98\;g}{molecular\;mass\;of\;solute}[/tex] = 0.00463
Molecular mass of solute = [tex]\rm \dfrac{0.98}{0.00463}[/tex]
Molecular mass of solute = 211.66 g/mol.
The molecular mass of the unknown has been 211.66 g/mol.
For more information about the molality of the solution, refer to the link:
https://brainly.com/question/8103026
How many water molecules are in a block of ice containing 0.500 mol of water (H2O)?
Answer:
3.01 × 10²³ molecules
Explanation:
Step 1: Given data
Moles of water (n): 0.500 mol
Step 2: Calculate the molecules of water present in 0.500 moles of water
In order to perform this calculation, we will use the Avogadro's number: in 1 mole of water there are 6.02 × 10²³ molecules of water.
0.500 mol × (6.02 × 10²³ molecules/1 mol) = 3.01 × 10²³ molecules
Grams of cl in 38g of cf3cl
Answer:
114 grams
Explanation:
3chlorines per compound*38grams=114
Which of the possible compounds has a mass of 163 grams when
6.13 x 1024 molecules of the compound is put on a scale?
Answer:
CH4
Explanation:
In solving this problem, we must remember that one mole of a compound contains Avogadro's number of elementary entities. These elementary entities include atoms, molecules, ions etc. Recall that one mole of a substance is the amount of substance that contains the same number of elementary entities as 12g of carbon-12. The Avogadro's number is 6.02 × 10^23.
Hence we can now say;
If 163 g of the compound contains 6.13 ×10^24 molecules
x g will contain 6.02 × 10^23 molecules
x= 163 × 6.02 × 10^23 / 6.13 × 10^24
x= 981.26 × 10^23/ 6.13 ×10^24
x= 160.1 × 10^-1 g
x= 16.01 g
x= 16 g(approximately)
16 g is the molecular mass of methane hence x must be methane (CH4)
The Ka1 value for oxalic acid is 5.9 x10-2 , and the Ka2 value is 4.6 x 10-5 . What are the values of Kb1 and Kb2 of the oxalate ion
Answer:
2.17x10⁻¹⁰ = Kb1
1.69x10⁻¹³ = Kb2
Explanation:
Oxalic acid, C₂O₄H₂, has two intercambiable protons, its equilibriums are:
C₂O₄H₂ ⇄ C₂O₄H⁻ + H⁺ Ka1 = 5.9x10⁻²
C₂O₄H⁻ ⇄ C₂O₄²⁻ + H⁺ Ka2 = 4.6x10⁻⁵
Oxalate ion, C₂O₄²⁻, has as equilibriums:
C₂O₄²⁻ + H₂O ⇄ C₂O₄H⁻ + OH⁻ Kb1
C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2
Also, you can know: KaₓKb = Kw
Where Kw is 1x10⁻¹⁴
Thus:
Kw = Kb2ₓKa1
1x10⁻¹⁴ =Kb2ₓ4.6x10⁻⁵
2.17x10⁻¹⁰ = Kb1And:
Kw = Kb1ₓKa2
1x10⁻¹⁴ =Kb1ₓ5.9x10⁻²
1.69x10⁻¹³ = Kb1
That is because the inverse reaction of, for example, Ka1:
C₂O₄H⁻ + H⁺ ⇄ C₂O₄H₂ K = 1 / Ka1
+ H₂O ⇄ H⁺ + OH⁻ K = Kw = 1x10⁻¹⁴
=
C₂O₄H⁻ + H₂O ⇄ C₂O₄H₂ + OH⁻ Kb2 = Kw × 1/Ka1
The monomer of poly(vinyl chloride) has the formula C2H3Cl. If there are 1,565 repeat units in a single chain of the polymer, what is the molecular mass (in amu) of that chain? Enter your answer in scientific notation.
Answer:
[tex]\large \boxed{9.780 \times 10^{4}\text{ u}}[/tex]
Explanation:
The molecular mass of a monomer unit is:
C₂H₃Cl = 2×12.01 + 3×1.008 + 35.45 = 24.02 + 3.024 + 35.45 = 62.494 u
For 1565 units,
[tex]\text{Molecular mass} = \text{1565 units} \times \dfrac{\text{62.494 u}}{\text{1 unit }} = \mathbf{9.780 \times 10^{4}}\textbf{ u}\\\\\text{The molecular mass of the chain is $\large \boxed{\mathbf{9.780 \times 10^{4}}\textbf{ u}}$}[/tex]
pls answer these questions for brainliest
katya is investigating displacement reactions . She heats the pairs of substances in this list
iron and aluminium oxide
iron and copper oxide
copper and magnesium oxide
iron and lead oxide
a)write down the letters os 2 pairs of substances that react . Explain your choices
b) choose one pair of substances that react . write a word equation for the reaction
A certain radioactive element has a half life of 8694 years. How much of a 8.30 g sample is left after 8323 years
Answer: The amount of sample left after 8323 years is 4.32g
Explanation:
Expression for rate law for first order kinetics is given by:
[tex]t=\frac{2.303}{k}\log\frac{a}{a-x}[/tex]
where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) for completion of half life:
Half life is the amount of time taken by a radioactive material to decay to half of its original value.
[tex]t_{\frac{1}{2}}=\frac{0.693}{k}[/tex]
[tex]k=\frac{0.693}{8694years}=7.97\times 10^{-5}years^{-1}[/tex]
b) amount left after 8323 years
[tex]t=\frac{2.303}{7.97\times 10^{-5}}\log\frac{8.30g}{a-x}[/tex]
[tex]8323=\frac{2.303}{7.97\times 10^{-5}}\log\frac{8.30g}{a-x}[/tex]
[tex]0.285=\log\frac{8.30}{a-x}[/tex]
[tex]\frac{8.30}{a-x}=1.92[/tex]
[tex](a-x)=4.32g[/tex]
The amount of sample left after 8323 years is 4.32g
For a given sample of C3H8(g), the enthalpy change during the reaction is -784kJ. How many grams of CO2 are produced? Group of answer choices g
Answer:
[tex]m_{CO_2}=46.6gCO_2[/tex]
Explanation:
Hello,
In this case, considering the combustion of propane:
[tex]C_3H_8(g)+5O_2(g)\rightarrow 3CO_2(g)+4H_2O(g)\ \ \ \Delta _CH=-2220.0 kJ/mol[/tex]
We can compute the burnt moles of propane as shown below:
[tex]n=\frac{-784kJ}{-2220.0 kJ/mol} =0.353molC_3H_8[/tex]
Then, by noticing propane and carbon dioxide are in a 1:3 molar ratio, we can compute the grams carbon dioxide by using the shown below stoichiometric procedure:
[tex]m_{CO_2}=0.353molC_3H_8*\frac{3molCO_2}{1molC_3H_8} *\frac{44gCO_2}{1molCO_2} \\\\m_{CO_2}=46.6gCO_2[/tex]
Best regards.
Which one of the following would have the largest dispersion forces?
A) CH3CH2SH
B) CH3NH2
C) CH4
D) CH3CH3
Answer:
A) CH3CH2SH
Explanation:
Dispersion forces are weak attractions found between non-polar and polar molecules. The attractions here can be attributed to the fact that a non-polar molecule sometimes become polar because the constant motion of its electrons may lead to an uneven charge distribution at an instant. If this happens, the molecule has a temporary dipole. This dipole can induce the neighbouring molecules to be distorted and form dipoles as well. The attractions between these dipoles constitute the Dispersion Forces.
Therefore; the greater the molar mass of a compound or molecule, the higher the Dispersion Force. This implies that the compound or molecule with the highest molar mass have the largest dispersion forces.
Now; for option (A)
CH3CH2SH
The molar mass is :
= (12 + (1 × 3 ) +12 + (1 ×2) + 32+1)
= (12 + 3+ 12 + 2 + 32 + 1)
= 62 g/mol
For option (B)
CH3NH2
The molar mass is:
= (12 + (1 × 3 ) +14 + (1 × 2)
= (12 + 3 + 14 + 2)
= 31 g/mol
For option (C)
CH4
The molar mass is :
= 12 + (1 × 4)
= 12 + 4
= 16 g/mol
For option (D)
CH3CH3
The molar mass is :
= 12 + ( 1 × 3 ) + 12 + ( 1 × 3)
= 12 + 3 + 12 + 3
= 30 g/mol
Thus ; option (A) has the highest molar mass, as such the largest dispersion force is A) CH3CH2SH
Which of the following pairings usually forms molecular compounds?
Select the correct answer below:
metal, nonmetal
nonmetal, nonmetal
metal, metal
none of the above
A nonmetal and a nonmetal will make molecular compounds like H2O and CO2
Strontium crystallizes in a face-centered cubic unit cell having an edge length of 77.43 pm. What is the atomic radius of strontium (in picometers) based on this structure
Answer:
Atomic radius of Strontium is 27.38pm
Explanation:
In a face-centered cubic structure, the edge, a, could be obtained using pythagoras theorem knowing the hypotenuse of the unit cell, b, is equal to 4r:
a² + a² = b² = (4r)²
2a² = 16r²
a = √8 r
As edge length of Strontium is 77.43pm:
77.43pm / √8 = r
27.38pm = r
Atomic radius of Strontium is 27.38pmWhat mass of benzene is cooled from 83.8 °C to 77.1 °C when 167 J of energy is transferred out of the system? (The specific heat of benzene is 1.740 J/g °C).
Answer:
14.32g
Explanation:
Initial temperature = 83.8°C
Final temperature = 77.1°C
Temperature change, ΔT = 83.8°C - 77.1°C = 6.7
Heat, H = 167J
Specific heat, c = 1.740J/g °C
m = ?
All these parameters are related with the equation below;
H = mcΔT
m = H / cΔT
m = 167 / (1.740 * 6.7)
m = 167 / 11.658 = 14.32g
How many moles of CO are produced when 1.2 moles C reacts? Equation: 5C(s)+2SO2(g)→CS2(l)+4CO(g)
Answer:
0.96 mol CO
Explanation:
We simply just use the reaction to help us find this:
[tex]1.2 mol C(\frac{4 mol CO}{5 mol C} )[/tex]
Multiply it out and we get 0.96 as our answer.
What is the systematic name for the given compound? (R)-2-bromobutane (S)-2-bromobutane (R)-2-butyl bromide (S)-2-butyl bromide
Answer:
See explanation below
Explanation:
IUPAC came up with the idea of an unambiguous system of nomenclature for organic compounds. This unambiguous system relates the structure of a compound with its name. Thus, IUPAC has established a worldwide standard for the unambiguous naming of organic compounds. Scientists all over the world can now have a uniform system of nomenclature for compounds in order to facilitate easy communication of scientific information.
The systematic names of the following compounds listed in the question are shown below;
(R)-2- butyl bromide has the systematic name (R)-2-bromobutane
(S)-2-butyl bromide has the systematic name (S)-2-bromobutane
This unified system of nomenclature avoids the confusion created by the use of different trivial names in deferent localities and by various scientific academies. This is a major advantage of the systematic nomenclature.
Which of the following functional groups is not present in the HIV protease inhibitor drug below called Saquinavir?
A) alcohol
B) amide
C) aromatic ring
D) amine
E) ketone N. ○ ト Saquinavir Structure
Answer:
alcohol
Explanation:
Since in its chemical structure it presents an amide, amine and aromatic ring group.
What this drug does is inhibit the protease of the HIV retrovirus, the protease is an enzyme that catalyzes proteins.
Suppose that you add 28.8 g of an unknown molecular compound to 0.250 kg of benzene, which has a K f Kf of 5.12 oC/m. With the added solute, you find that there is a freezing point depression of 3.06 oC compared to pure benzene. What is the molar mass of the unknown compound
Answer:
THE MOLAR MASS OF THE UNKNOWN COMPOUND IS 242.02 g/mol.
Explanation:
First:
Calculate the change in freezing point:
Freezing point of pure benzene = 5.5°C
Change in temperature = 5.5 - 3.06 = 2.44 °C
Second:
Using the formula:
Δt = i Kf m
Let's assume i = 1
Kf = 5.12 °C/m
M = x / 0.250 kg of benzene
Then we can calculate x which is the molarity
Re-arranging the formula, we have:
m = Δt / i Kf
x / 0.250 = 2.44 / 1 * 5.12
x = 2.44 * 0.250 / 5.12
x = 0.61 / 5.12
x = 0.119 M
Since it is well known that molarity is the mass of a substance divided by its molar mass. We can then calculate the molar mass.
Molar mass = Mass / molarity
Molar mass = 28.8 g / 0.119 M
Molar mass =242.02 g/mol
Hence, the molar mass of the unknown molecular compound is 242.02 g/mol.
What is the new mass/volume percent (m/v) of a KOH solution that is prepared by diluting 110 mL of a 6.0% (m/v) KOH solution to 330 mL
Answer:
The new mass/volume percent is 2.0% (m/v)
Explanation:
Dilution is a procedure by which the concentration of a solution is decreased, generally with the addition of a diluent. In other words, dilution is a process in which a concentrated solution is always started, to which a greater volume of solvent is added, causing the concentration and volume of the resulting solution to change. But the amount of solute used to prepare the initial solution remains the same.
The calculation of a dilution is made by:
Cinitial. Vinitial = Cfinal. Vfinal
where C indicates concentration and V indicates volume.
In this case:
Cinitial: 6.0% (m/v)Vinitial: 110 mLCfinal: ?Vfinal: 330 mLReplacing:
6.0% (m/v) * 110 mL= Cfinal* 330 mL
Solving:
[tex]Cfinal=\frac{ 6.0 (m/v)*110 mL}{330 mL}[/tex]
Cfinal= 2.0% (m/v)
The new mass/volume percent is 2.0% (m/v)