Answer:
Magnesium.
Explanation:
Because it is in group II
Lead of mass 0.75kg is heated from 21°c to its melting point and continues to be heated unit it has all melted. Calculate how much energy is supplied to the lead. [Melting point of lead 372.5°c specific latent heat of fusion of lead = 23000 Jkg 'k ']
Answer:
65.5J
Explanation:
ML=Q
ML=MC(change in temperature)
0.75 X 23000 =0.75 X 351 X C
C= 65.5J
The energy supplied to the lead to melt from 21°c to its melting point is 51521 Joules.
What is the specific heat capacity?Specific heat is the amount of heat energy supplied to change the temperature of one unit mass of a substance by 1 °C. The SI unit of the specific heat capacity of a substance is J/Kg.
The mathematical expression for the specific heat capacity can be written as:
Q = mCΔT Where C is the specific heat of the substance.
The specific heat capacity depends upon the starting temperature and is an intensive characteristic of the material.
Given, the melting point of the lead T₂ = 327.5° C
The initial temperature of the lead, T₁ = 21° C
The latent heat of the lead given, L = 230000 J/Kg K
The specific heat of the lead, C = 130 J/Kg K
The heat required to melt the lead from 12°C to 327.5 °C is :
Q = m× [C × (T₂ - T₁) + L ]
Q = 0.75 × [0.130 (327.5 - 21) + 23000]
Q = 51521 J
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using the balanced equation below how many grams of lead(||) sulfate would be produced from the complete reaction of 23.6 g lead (|V) oxide
Answer:
59.8 g of PbSO₄.
Explanation:
The balanced equation for the reaction is given below:
Pb + PbO₂ + 2H₂SO₄ —> 2PbSO₄ + 2H₂O
Next, we shall determine the mass of PbO₂ that reacted and the mass of PbSO₄ produced from the balanced equation. This can be obtained as follow:
Molar mass of PbO₂ = 207 + (16×2)
= 207 + 32
= 239 g/mol
Mass of PbO₂ from the balanced equation = 1 × 239 = 239 g
Molar mass of PbSO₄ = 207 + 32 + (16×4)
= 207 + 32 + 64
= 303 g/mol
Mass of PbSO₄ from the balanced equation = 2 × 303 = 606 g
SUMMARY:
From the balanced equation above,
239 g of PbO₂ reacted to produce 606 g of PbSO₄.
Finally, we shall determine the mass of PbSO₄ that will be produced by the reaction of 23.6 g of PbO₂. This can be obtained as follow:
From the balanced equation above,
239 g of PbO₂ reacted to produce 606 g of PbSO₄.
Therefore, 23.6 g of PbO₂ will react to produce = (23.6 × 606) / 239 = 59.8 g of PbSO₄.
Thus, 59.8 g of PbSO₄ were obtained from the reaction.
A sample of gas in a balloon has an initial temperature of 18 ∘C and a volume of 33 L. If the temperature changes to 47 ∘C, and there is no change of pressure or amount of gas, what is the new volume, V2, of the gas?
Answer:
The final volume of the sample of gas is 36.287 liters.
Explanation:
Let suppose that sample of gas is a closed system, that is, a system with no mass interactions with surroundings, and gas is represented by the equation of state for ideal gases, which is described below:
[tex]P\cdot V = n\cdot R_{u}\cdot T[/tex] (1)
Where:
[tex]P[/tex] - Pressure, in atmospheres.
[tex]V[/tex] - Volume, in liters.
[tex]n[/tex] - Molar quantity, in moles.
[tex]T[/tex] - Temperature, in Kelvin.
[tex]R_{u}[/tex] - Ideal gas constant, in atmosphere-liters per mole-Kelvin.
As we know that sample of gas experiments an isobaric process, we can determine the final volume by the following relationship:
[tex]\frac{T_{1}}{V_{1}} = \frac{T_{2}}{V_{2}}[/tex] (2)
Where:
[tex]V_{1}[/tex] - Initial volume, in liters.
[tex]V_{2}[/tex] - Final volume, in liters.
[tex]T_{1}[/tex] - Initial temperature, in Kelvin.
[tex]T_{2}[/tex] - Final temperature, in Kelvin.
If we know that [tex]V_{1} = 33\,L[/tex], [tex]T_{1} = 291.15\,K[/tex] and [tex]T_{2} = 320.15\,K[/tex], then the final volume of the gas is:
[tex]V_{2} = V_{1}\cdot \left(\frac{T_{2}}{T_{1}} \right)[/tex]
[tex]V_{2} = 33\,L \times \frac{320.15\,K}{291.15\,K}[/tex]
[tex]V_{2} = 36.287\,L[/tex]
The final volume of the sample of gas is 36.287 liters.
If a buffer is composed of 23.34 mL of 0.147 M acetic acid and 33.66 mL of 0.185 M sodium acetate, how many mL of 0.100 M NaOH can be added before the buffer capacity is reached
Answer:
25.5mL of 0.100M NaOH are needed to reach buffer capacity.
Explanation:
The buffer capacity is reached when the ratio between moles of conjugate base (Sodium acetate) and moles of weak acid (Acetic acid) is 10:
Moles sodium acetate / Moles Acetic acid = 10
The reaction of acetic acid, HA, with NaOH, to produce sodium acetate, NaA is:
HA + NaOH → H2O + NaA
That means the moles of NaOH added = Moles of HA that are being subtracted and moles of NaA that are been produced.
The initial moles of each species is:
Acetic acid:
23.34mL = 0.02334L * (0.147mol / L) = 0.00343 moles Acetic Acid
Sodium Acetate:
33.66mL = 0.03366L * (0.185mol / L) = 0.00623 moles Sodium Acetate
We can write the moles of each species when NaOH is added as:
Moles sodium acetate / Moles Acetic acid = 10
0.00623 moles + X / 0.00343 moles - X = 10
Where X are moles of NaOH added
Solving for X:
0.00623 moles + X = 0.0343 moles - 10X
11X = 0.0281
X = 0.00255 moles of NaOH are needed
In Liters:
0.0255mol NaOH * (1L / 0.100mol) = 0.0255L of 0.100M NaOH are needed =
25.5mL of 0.100M NaOH are needed to reach buffer capacity
Which of the following is classified as paramagnetic?
1.NO(+)
2.Be2
3.B2(+)
4.+N2(+)
Determine the highest level of protein structure described by each item.
a. Primary structure
b. Secondary structure
c. Tertiary structure
d. Quaternary structure
1. order of amino acids
2. overall macromolecule structure containing more than one polypeptide chain
From each of the protein structures listed, the option with the highest level of protein structure as regards with order of amino acids and overall macromolecule structure is quaternary structure. That is option D.
The protein one of the essential nutrients that is found in and consumed by mammals.
There are different types of proteins and their functions depends on their shape, structure or conformation.
The structure of proteins include:
Primary structure: This is the simplest shape of proteins. This is because, the amino acids of a polypeptide is arranged in a linear form.Secondary structure: This is the local folded structures that form within a polypeptide due to interactions between atoms of the backbone.Tertiary structure: These are three dimensional structures of proteins that occurs as a result of the interactions between the R groups of the amino acids that make up the protein.Quaternary structure: This protein structure contains multiple polypeptide chains also called subunits.Therefore, the option with the highest level of protein structure as regards with order of amino acids and overall macromolecule structure is quaternary structure.
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To prepare a standard (calibration) curve for a spectroscopy experiment, start by preparing ___________ with ______________ Then, measure the ______________ of each solution at _____________ and create a plot of ____________ for the measured values. Finally, find the best-fit line of the data set.
Answer: See explanation
Explanation:
The calibration curve is the method used for the determination of the concentration of a substance such that the unknown sample will be compared to some standard samples of the known concentration.
To prepare a standard (calibration) curve for a spectroscopy experiment, start by preparing (multiple solutions) with (different known concentrations). Then, measure the (absorbance) of each solution at (thesame wavelength) and create a plot of (absorbance vs. concentration) for the measured values. Finally, find the best-fit line of the data set.
The peptide alanylglutamylalanylglycylalanylleucine has:
No free carboxyl groups
Five peptide bonds
A disulphide bridge
Two free amino groups
Peptide bonds are formed between carboxyl groups of one amino acid and amino group of another dehydration synthesis.
The correct answer is Five Peptide bonds
The peptide of "alanylglutamylalanylglycylalanylleucine" will have four or more peptide bonds.
It will also have free carboxyl groups.
The chain of amino acids is polypeptide.
Usually C terminal amino acid is the residual at the end of peptide bonds formation.
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Choose the correct statement
a) The maximum value of principal quantum number (n) is 7
b) The angular quantum number (l) can receive value from 1 to (n-1)
c) The magnetic quantum number (ml) shows the energy of electron
d) The magnetic quantum number (ml) show how many orbitals in each subshell
Answer:
maybe number b is correct. ...thank you
Suppose you are studying the Ksp of CaCl2, which has a molar mass of 110.98 g/mol, at multiple temperatures. You dissolve 4.99 g of CaCl2 in 10.0 mL of water at 100 oC and cool the solution. At 90 oC, a solid begins to appear. What is the Ksp of CaCl2 at 90 oC
Answer:
Hence the Solubility product,
Ksp = [Ca2+] [Cl-]2
or, Ksp = (4.5) (9)2
or, Ksp = 364.5
Explanation:
Mass of CaCl2 = 4.99 g
Molar mass of CaCl2 = 110.98 g/mol
Moles of CaCl2
= given mass/ molar mass
= 4.99/ 110.98
= 0.045
Volume = 10.0 mL = 0.01 L
CaCl2 dissociates into its ion as:
CaCl2 (s) \rightleftharpoons Ca2+ (aq) + 2 Cl- (aq)
At 90°C, the solution is saturated with Ca2+ and Cl- ions.
Moles of Ca2+ = Moles of CaCl2 dissolved = 0.045
Moles of Cl- = 2 x ( Moles of CaCl2 dissolved) = 2 x 0.045 = 0.09
[Ca2+] = Moles/ Volume = 0.045/ 0.01 = 4.5 M
[Cl-] = 0.09/ 0.01 = 9 M
Solubility product,
Ksp = [Ca2+] [Cl-]2
or, Ksp = (4.5) (9)2
or, Ksp = 364.5
Standard hydrogen electrode acts as both anode and cathode.Explain.
Answer:
A Standard Hydrogen Electrode is an electrode that scientists use for reference on all half-cell potential reactions. The value of the standard electrode potential is zero, which forms the basis one needs to calculate cell potentials using different electrodes or different concentrations. It is important to have this common reference electrode, just as it is important for the International Bureau of Weights and Measures to keep a sealed piece of metal that is used to reference the S.I. Kilogram.
Answer:
The role of an electrode as cathode or anode depends on the nature and electrode potential of the other electrode with which it forms the complete electrochemical cell.
When a cell is to be made with zinc electrode and hydrogen electrode, the hydrogen electrode will behave as a cathode and the zinc electrode will behave as anode because zinc is present above hydrogen in the activity series. That is zinc is more electropositive than hydrogen.
If the cell is made with a copper electrode and hydrogen electrode, the hydrogen electrode will behave as anode and the copper electrode as a cathode. This is due to the fact that Cooper is present below hydrogen in the activity series. Copper is less electropositive than hydrogen.
Explanation:
How does the radiation from radioisotopes cause damage to human tissue?
Answers
A.
by ionization knocking electrons away from atoms
B.
by breaking the bonds between atoms in molecules
C.
by causing nuclear chain reactions inside cells
D.
by causing transmutations of atoms within cells
Answer:
Explanation:
B.
by breaking the bonds between atoms in molecules
You perform a distillation to separate a mixture of propylbenzene and cyclohexane, and you obtain 2.9949 grams of cyclohexane (density -0.779 g/mL, MW - 84.16 g/mol) and 1.6575 grams of propylbenzene (density = 0.862 g/mL, MW = 120.2 g/mol). What is the volume percent composition of cyclohexane in the mixture?
Answer:
66.67%
Explanation:
From the given information:
mass of cyclohexane = 2.9949 grams
density of cyclohexane = 0.779 g/mL
Recall that:
Density = mass/volume
∴
Volume = mass/density
So, the volume of cyclohexane = 2.9949 g/ 0.779 g/mL
= 3.8445 mL
Also,
mass of propylbenzene = 1.6575 grams
density of propylbenzene = 0.862 g/mL
Volume of propylbenzene = 1.6575 g/ 0.862 g/mL
= 1.9229 mL
The volume % composition of cyclohexane from the mixture is:
[tex]= (\dfrac{v_{cyclohexane}}{v_{cyclohexane}+v_{propylbenzene}})\times 100[/tex]
[tex]= (\dfrac{3.8445}{3.8445+1.9229})\times 100[/tex]
[tex]= (\dfrac{3.8445}{5.7674})\times 100[/tex]
= 66.67%
Spell out the full name of the compound.
Answer:
it is propane
C3H8 it is propane
The Full name of the given compound is Propane.
What is Propane ?Propane is a three-carbon alkane with the molecular formula C₃H₈.
It is a gas at standard temperature and pressure, but compressible to a transportable liquid.
In the figure given ;
Black balls represents Carbon atomsWhite balls represents Hydrogen atomsIn the given figure, there is single bond present between Carbon and Hydrogen. Hence, The Full name of the given compound is Propane.
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Complete and balance the nuclear equations for the following fission reactions.
a. 23592U+10n→16062Sm+7230Zn+?10n. Express your answer as a nuclear equation.
b. 23994Pu+10n→14458Ce+?+210n
Answer:
23592U+10n→14454Xe+9038Sr+210n
Explanation:
a nuclear reaction for the neutron-induced fission of U−235 to form Xe−144 and Sr−90.
Na Sa Bant HCL -> 50g Hao pt Soy
North America and south africa
The half life for the decay of carbon-14 is 5.73 times 10^3 years.
Suppose the activity due to the radioactive decay of the carbon-14 in a tiny sample of an artifact made of wood from an archeological dig is measured to be 77.The activity in a similar-sized sample of fresh wood is measured to be 85.Calculate the age of the artifact. Round your answer to 2 significant digits.
Answer:
790 years
Explanation:
Given that;
0.693/t1/2 = 2.303/t log [A]o/[A]
So;
t1/2 =half life of carbon-14
t= age of the sample
[A]o= activity of the living sampoke
[A] = activity at time t
0.693/5.73 ×10^3 = 2.303/t log 85/77
1.21 × 10^-4 = 2.303/t log 1.1
1.21 × 10^-4 = 0.0953/t
t= 0.0953/1.21 × 10^-4
t= 790 years (to 2sf)
Calculate the mass percent of each component in the following solution.
159 g NiCl2 in 500 g water
% Nicla
% water
Answer:
% NiCl2 = 24.13%
% water = 78.57%
Explanation:
Mass percentage = mass of solute/mass of solution × 100
According to this question, a solution contains 159 g of NiCl2 in 500 g of water. Hence, mass of the solution is calculated as follows:
Mass of solution = 159g + 500g
Mass of solution = 659g
Therefore;
A) % Mass of NiCl2 in solution = mass of NiCl2/mass of solution × 100
% Mass of NiCl2 in solution = 159/659 × 100
% Mass of NiCl2 in solution = 0.2413 × 100
= 24.13%
B) % Mass of water in solution = mass of water/mass of solution × 100
% Mass of water in solution = 500/659 × 100
% Mass of water in solution = 0.7587 × 100
% Mass of water in solution = 75.87%
The sample concentration was measured at 50mg/ml. The loading concentration needs to be 10mg/ml. The final volume needs to be 25ul. What is the volume of sample needed and the amount of buffer needed to reach 25ul
Answer:
a) [tex]V_1=5ul[/tex]
b) [tex]v=20ul[/tex]
Explanation:
From the question we are told that:
initial Concentration [tex]C_1=50mg/ml[/tex]
Final Concentration [tex]C_2=10mg/ml[/tex]
Final volume needs [tex]V_2 =25ul[/tex]
Generally the equation for Volume is mathematically given by
[tex]C_1V_1=C_2V_2[/tex]
[tex]V_1=\frac{C_1V_1}{C_2}[/tex]
[tex]V_1=\frac{10*25}{50}[/tex]
[tex]V_1=5ul[/tex]
Therefore
The volume of buffer needed is
[tex]v=V_2-V_1\\\\v=25-5[/tex]
[tex]v=20ul[/tex]
What conversion factor would we need to convert moles of helium to atoms of helium?
Explanation:
The conversion factor required to convert moles of helium to atoms of helium is equal to 6.023*10²³ (NA). Helium is a monoatomic gas. Each molecule of helium gas contains one atom of helium. Therefore, one mole of helium gas will contain one mole atoms of helium.
If the balance were not tared prior to weighing out the KHP.... how would you expect this to affect the molarity of NaOH calculated? What type of error is this?
Answer:
Following are the response to the given question:
Explanation:
In the given scenario, When the balance has never been tainted before the KHP is weighted, which can affect the molar concentration of NaOH because its molarity is directly proportional to the weight including its substance. In this question it is the mistake is systemic because it may be corrected by modifying balancing parameters.
Please help answering 11)
Answer:
the answer is C
Explanation:
You are working in a lab when radiation alarms go off. You are able to hide inside a steel cabinet, whose sides are about 1.5 inches thick, until the alarm goes off. Preliminary reports show that the radiation was weakly ionizing and negatively charged. Were you safe in the cabinet?
A. Yes, it was beta radiation and the steel was enough to block it.
B. Yes, it was alpha radiation and not harmful.
C. No, it was beta radiation and very dangerous.
D. No, it was gamma radiation and can only be blocked by a thick wall of lead.
Answer
A
Explanation:
Beta radiation is only very dangerous when it is ingested or if there is nothing in the way. The steel should protect you.
Yes, it was beta radiation and the steel was enough to block it. Hence, option A is correct.
What is beta radiation?Beta radiation is a current of electrons released at a rate exceeding the speed of light, with kinetic energy between 0.2 MeV and 3.2 MeV. Due to their lower mass which is approximately 5.5×[tex]10^{-4}[/tex] amu (9.130×[tex]10^(-24)[/tex], interactions between β-particles and the atoms of pass-through materials are much less frequent than the interactions between 5-007-particles: less than 200 ion pairs are typically formed in each centimetre of the air passage.
When we are working in a lab when radiation alarms go off and we are able to hide inside a steel cabinet, whose sides are about 1.5 inches thick, until the alarm goes off.
Preliminary reports show that the radiation was weakly ionizing and negatively charged. Yes, it was beta radiation and the steel was enough to block it.
Hence, option A is correct.
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Adding more than one equivalent of HCl to pent-1-yne will lead to which product:______.
a. 1,2-dichloro-1-butene.
b. 1,1-dichloropentane.
c. 2,2-dichloropentane.
d. 2,2-dichlorobutane.
Answer:
c. 2,2-dichloropentane.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to firstly draw the structure of the reactant, pent-1-yne:
[tex]CH\equiv C-CH_2-CH_2-CH_2[/tex]
Now, we infer the halogen is added to the carbon atom with the most carbon atoms next to it, in this case, carbon #2, in order to write the following product:
[tex]CH\equiv C-CH_2-CH_2-CH_2+2HCl\rightarrow CH_3- CCl_2-CH_2-CH_2-CH_2[/tex]
Whose name is 2,2-dichloropentane.
Regards!
Which statement best describes what happens during a chemical reaction?
A. Reactants change into products.
B. Reactants change into new reactants.
C. Products change into reactants.
D. Products change into new products.
Answer:
A. Reactants change into products
Which of the following behaviors would best describe someone who is listening and paying attention? a) Leaning toward the speaker O b) Interrupting the speaker to share their opinion c) Avoiding eye contact d) Asking questions to make sure they understand what's being said
Answer:
a Leaning towards the speaker
công thức phân tử của glucozo
C₆H₁₂O₆ is the molecular formula of gulcozo.
does anyone know how to solve this and what the answer would be?
Dynamic equilibrium is showed at the point at which solid liquid and gas intersect.
At the point at which solid liquid and gas intersect represents a system that shows dynamic equilibrium. There is equal amount of reactants and products at the point of dynamic equilibrium because the transition of substances occur between the reactants and products at equal rates, means that there is no net change. Reactants and products are formed at the rate that no change occur in their concentration.
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Phosphagens are a group of molecules that includes creatine phosphate (in vertebrates), and arginine phosphate, lombricine, and phosphoopheline (in invertebrates). These molecules have similar functions in different organisms.
a. True
b. False
Answer: True
Explanation:
Phosphagens are high energy storage compounds that are usually found in the tissue of animals.
Based on the question, the molecules have similar functions in different organisms such as the fact that they can accept phosphoryl groups from ATP in a situation where the ATP is in excess. Also, they donate phosphoryl groups to ADP in order for the regeneration of ATP.
An ordinary gasoline can measuring 30.0 cm by 20.0 cm by 15.0 cm is evacuated with a vacuum pump.
1a. Assuming that virtually all of the air can be removed from inside the can, and that atmospheric pressure is 14.7 psi, what is the total force (in pounds) on the surface of the can?
1b. Do you think that the can could withstand the force?
Answer:
Explanation:
From the given information:
The surface area of the can = (30 × 20 × 2) +(20× 15 × 2) +(30 × 15 × 2)
= 1200 + 600 + 900
= 2700 cm²
Since 1 inch² = 0.155 inch²
The surface area in inches² = 2700 × 0.155 inch²
= 418.5 inches²
The total force can be determined by using the expression:
Force = Pressure ×Area
Force = 14.7 psi × 418.5 inches²
Force = 6151.95 lbs
Yes, the gasoline can will be able to withstand the force.
