Answer:
The correct answer is 84.81 °C.
Explanation:
Based on the given information, the volume or mass of coffee is 250 ml, and the mass of metal spoon is 80 grams. The specific heat capacity of metal spoon is 0.80 J/g °C, and the specific heat capacity of coffee is 4.18 J/g °C. In the given case, heat is lost from the coffee and is gained by the spoon.
For finding the final temperature of the coffee, the formula to be used is Q = msΔT, here m is the mass, s is the specific heat, and ΔT is the change in temperature.
Heat lost from the coffee = Heat gained by the spoon
250 × 4.18 (90 - T2) = 80 × 0.8 (T2 - 0)
1045 (90 - T2) = 64 (T2 -0)
94050 - 1045 T2 = 64 T2
94050 = 1045 T2 + 64 T2
94050 = 1109 T2
T2 = 84.84 °C
Determine whether each of the following salts will form a solution that is acidic, basic, or pH-neutral.
a. KCl
b. NaClO
Answer:
a. Neutral
b. Basic
Explanation:
To determine which of the salts are acidic, neutral or basci we should dissociate them and determine if the ions, can make hydrolysis to water.
KCl → K⁺ + Cl⁻
We need to know, where do the ions come from. In this case, K⁺ comes from the KOH which is a strong base and Cl⁻ comes from the HCl, a strong acid. In conclussion, both are the conjugate weak acid and base, respectively. They do not make hydrolysis, so this salt is neutral. No protons or hydroxides are given.
NaClO → Na⁺ + ClO⁻
The Na⁺ comes from the NaOH, it is the conjugate weak acid from a strong base, while the ClO⁻ comes from the HClO, a weak acid. This means that the ClO⁻ can react to water, to make hydrolysis. The equilibrium will be:
ClO⁻ + H₂O ⇄ HClO + OH⁻
We are giving hydroxides to medium, so the salt is basic.
Which of the following characteristics is common to both acids and bases? They produce ions when dissolved in water They absorb oxygen ions when dissolved in water They increase hydrogen ions when dissolved in a solution They increase the hydroxide ions when dissolved in a solution
Answer:
They produce ions when dissolved in water.
Explanation:
Acids and bases have the characteristic in common to each other. Both of them have the property of reacting and dissolving in the water. Both acids and bases lead to the production of the ions when they are placed in a water solution. Acids produce Hydrogen ions when they are dissolved in water. Bases produce hydroxide ion when they are dissolved in water.
Answer:
A
Explanation:
calculate the number of neutrons in the chlorine 17Cl35 and 17Cl37 ?
Answer: chlorine 17Cl35 has 18 neutrons, and 17Cl37 has 20 neutrons
Explanation: 17 is the atomic number of chlorine which tells us what is the number of protons in chlorine nucleus. 35 and 37 is the mass number of two isotopes of chlorine, it tells us what is the total number of protons and neutrons in atomic nucleus of two chlorine isotopes .
Now to know how many neutrons are in both isotopes we have to substract the number of protons from the mass number of each isotope
For 17Cl35 it will be 35- 17 what makes 18 and for 17 Cl 37 it will be 20 neutrons
Which of these species would you expect to have the highest standard entropy (S°)?
a. CH4(g)
b. C2H2(g)
c. C2H4(g)
d. C2H6(g)
e. C3H8(g)
Answer:
e. C₃H₈(g)
Explanation:
Standard entropy is the absolute entropy of a substance at 1 atm and 25°C.
For different substances in the same phase, molecular complexity determines which ones have higher entropies.
Consider the gases CH₄, C₂H₂, C₂H₄, C₂H₆, C₃H₈. Propane (C₃H₈) has a more complex structure and hence more ways to execute molecular motions, which also increase its microstates. Therefore, propane has the greatest standard entropy.
The standard entropy of propane has been highest among the given molecules. Thus, option E is correct.
The standard entropy has been the energy possessed by the 1 mole of a pure substance at standard pressure and temperature.
The entropy has been proportional to the molecular weight and structure complexity. The molecule with higher molecular weight and structure complexity tends to have higher entropy.
In the given set of molecules, the molecular mass and structure complexity of propane has been the highest. Thus, the standard entropy of propane has been highest among the given molecules. Option E is correct.
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Which of the following liquids would have the highest viscosity at room temperature?
1) CH3OCH3
2)CH2Cl2
3) C2H5OH
4) CH3Br
5)HOCH2CH2OH
Answer:
5)HOCH2CH2OH
Explanation:
This is also known as ethylene glycol. An increase in hydrogen bonds of a compound means an increase in the viscosity. Hydrogen bonds occur as a result of bonding with electronegative elements such as Oxygen, Nitrogen etc.
The compounds with the highest amount of Hydrogen bond represents the one with the highest viscosity which is B) HOCH2CH2OH
The liquid which would have the highest viscosity at room temperature is: Choice 5): HOCH2CH2OH.
Discussion:
The compound HOCH2CH2OH, named ethylene glycol relative to the other compounds has more hydrogen bonding.
By convention, an increase in the number of hydrogen bonds of a compound means an increase in the viscosity.
Hydrogen bonds are characterized by the of hydrogen with electronegative elements such as Oxygen, Nitrogen etc.
The compounds with the highest amount of Hydrogen bond is therefore; HOCH2CH2OH.
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Which of the following has the greatest electronegativity difference between the bonded atoms?
A) A strong acid made of hydrogen and a halogen, such as HCl
B) A diatomic gas, such as nitrogen (N2)
C) Cartoon bonded to a group 6A (16) nonmetal chalcogen, such as in Co
D) A group 1 alkali metal bonded to chloride, such as RbCl
Answer:
D) A group 1 alkali metal bonded to chloride, such as RbCl
Explanation:
Which of the following has the greatest electronegativity difference between the bonded atoms?
A) A strong acid made of hydrogen and a halogen, such as HCl
The electronegativity difference between H and Cl is:
ΔEN = |EN(H)-EN(Cl)| = |2.1-3.0| = 0.9
B) A diatomic gas, such as nitrogen (N₂)
The electronegativity difference between N and N is:
ΔEN = |EN(N)-EN(N)| = |3.0-3.0| = 0.0
C) Carbon bonded to a Group 6A (16) nonmetal chalcogen, such as in CO
The electronegativity difference between C and O is:
ΔEN = |EN(C)-EN(O)| = |2.5-3.5| = 1.0
D) A group 1 alkali metal bonded to chloride, such as RbCl
The electronegativity difference between Rb and Cl is:
ΔEN = |EN(Rb)-EN(Cl)| = |0.8-3.0| = 2.2
A concentration cell is one in which both the anode and cathode are the same but with different concentrations. Calculate the cell potential with [Zn2+] = 0.10 M[Zn2+] = 0.10 M for the cathode and the [Zn2+] = 0.010 M[Zn2+] = 0.010 M for the anode?
Answer: 0.029 V
Explanation:
For the given chemical reaction :
[tex]Zn^{2+}(0.10M)(aq)+Zn(s)\rightarrow Zn^2+{0.010M)(aq)+Zn(s)[/tex]
Using Nernst equation :
[tex]E_{cell}=E^0_{cell}-\frac{2.303RT}{nF}\log\frac{\text {anodic ion concentration}}{\text {cathodic ion concentration}}[/tex]
where,
F = Faraday constant = 96500 C
R = gas constant = 8.314 J/mol.K
T = room temperature = 298 K
n = number of electrons in oxidation-reduction reaction = 2
[tex]E^0_{cell}[/tex] = standard electrode potential of the cell = 0 (as both metals are same )
[tex]E_{cell}[/tex] = emf of the cell = ?
[tex]E_{cell}=0-\frac{2.303\times 8.314\times 298}{2\times 96500}\log\frac{0.010}{0.10}[/tex]
[tex]E_{cell}=0.029V[/tex]
Thus the cell potential will be 0.029 V
Write the Ksp expression for the sparingly soluble compound chromium(III) hydroxide, Cr(OH)3.
Ksp =________
Answer and Explanation: Ksp is the Solubility Product Constant and is the equilibrium constant that happens when a solid is dissolved in an aqueous solution.
The dissolution of chromium (III) hydroxide:
[tex]Cr(OH)_{3}_{(s)}[/tex] ⇄ [tex]Cr^{3+}_{(aq)} + 3OH^{-}_{(aq0)}[/tex]
Every equilibrium constant is of the form:
[tex]K = \frac{[products]^{coefficient}}{[reagents]^{coefficient}}[/tex]
Then,
[tex]K_{sp} = [Cr^{3+}_{(aq)}][OH^{-}_{aq}]^{3}[/tex]
The reagent is not included because solids don't take part in euqilibrium constants.
So, Ksp of chromium (III) hydroxide is [tex]K_{sp} = [Cr^{3+}_{(aq)}][OH^{-}_{aq}]^{3}[/tex]
For the reaction of hydrochloric acid and sodium thiosulfate, the rate law is written as:______
A. Rate = k [HCl]m [Na2S2O3]n
B. Rate = k [HCl + Na2S2O3]
C. Rate = t [HCl]a [Na2S2O3]x
D. Rate = t [HCl + Na2S2O3]
Answer:
A. [tex]Rate =k[HCl]^{m} [Na_2S_2O_3]^{n}[/tex]
Explanation:
Let's consider the reaction between hydrochloric acid and sodium thiosulfate.
2 HCl + Na₂S₂O₃ → H₂O + S + SO₂ + 2 NaCl
The rate law is:
[tex]Rate =k[HCl]^{m} [Na_2S_2O_3]^{n}[/tex]
where,
Rate is the reaction ratek is the rate constantm and n are the reaction orders, which can only be determined experimentally and may or not coincide with the stoichiometric coefficients.If we add a catalyst to the following equation, CO + H2O + heat CO2 + H2, which way will the equilibrium shift?
Answer:
No effect.
Explanation:
Hello,
In this case, considering the widely studied Le Chatelier's principle, we can realize that the factors affecting equilibrium are concentration, temperature and pressure and volume if the reaction is in gaseous phase and with non-zero change in the number of moles. In such a way, by adding a catalyst to given reaction will have no effect on the equilibrium direction.
Best regards.
How many atoms are represented by one formula unit of aluminum chromate, Al2(CrO4)3
Answer:
17 atoms
Explanation:
If what we want is to calculate the number of atoms. We must take into account the subscripts of the formula. We can rewrite the formula taking into account the "ones" implicit in the formula, therefore we will have:
[tex]Al_2(Cr_1O_4)_3 [/tex]
Now we have a "3" outside the parenthesis. Therefore, we must multiply this 3 by the number of atoms within the parentheses:
-) Oxygen atoms: 4 x 3 = 12 atoms
-) Chromium atoms: 1 x 3 = 3 atoms.
If we take into account we have 2 aluminum atoms, in total, we will have:
-) 12 oxygen atoms
-) 3 chromium atoms
-) 2 aluminum atoms
12 + 3 + 2 = 17 atoms
In total, we will have 17 atoms.
See figure 1
I hope it helps!
Lab safety is not only important in the classroom, but it is also important to follow
the rules at home, or on the bus. Accidents can happen anywhere and if proper safety
precautions aren't followed, someone can get hurt.
Last year in New York, students were burned when they were showing off their
science project at the bus stop.
In Rhode Island, a student kept chemicals in his locker for a later experiment, the
chemicals combined and exploded hurting students in the hallway.
In Brazil, students were practicing their experiment in a friend's garage, without
adult supervision, when there was an explosion. The explosion killed all 4 students.
Science can be a lot of fun but it is also dangerous if you aren't following safety
precautions.
Questions: Answer on the following slide.
1. What is needed from adults when conducting experiments at home?
2. What should always be followed when conducting experiments?
3. Why are chemicals so dangerous?
4. What is science?
YO
Answer:
Follow safety measures and safety rules to avoid any accident.
Explanation:
1. Follow all safety measures is needed from adults when they conducting any experiment at home in order to prevent any damage occurs due to that experiment.
2. Safety rules should always be followed when conducting an experiment at any place such as at home, class room and laboratory etc in order to avoid any accident.
3. Some chemicals are very dangerous because they are flammable and catch fire when allow it to the heat source. Some chemicals also cause suffocation by absorbing all the oxygen from the environment and as a result death occurs.
4. Science is a systematic study of physical objects through observation and experiments. Science is a knowledge gain from experiments.
Which of the following pairs of aqueous solutions would not produce a reaction when mixed? Select one: a. NaNO3 and CuCl2 b. Ba(OH)2 and HNO3 c. CaCl2 and Na3PO4 d. AgNO3 and HCl
Answer:
a. NaNO3 and CuCl2
Explanation:
The other 3 react as follows:
Ba(OH)2 and HNO3 ---> BaNO3 + H2O
CaCl2 + Na3PO4 ---> CaPO4 + NaCl
AgNO3 + HCl ---> AgCl + HNO3
What is the density if the mass of your object is 54.6g and the volume is 15.30 mL?
Answer:
5ml
Explanation:not sure why
A 175.3 mg sample of C10H12O2 was dissolved in 1.50 g of chloroform (Kb = 3.63 °C/m). What is the boiling point of this solution.
Answer:
[tex]Tb=63.8\°C[/tex]
Explanation:
Hello,
In this case, for the boiling point elevation, we have:
[tex]\Delta T=i*m*Kb[/tex]
Whereas the van't Hoff factor for the given substance is 1 since is not ionizing. Moreover, the molality is computed by:
[tex]m=\frac{mol_{solute}}{m_{solvent}}=\frac{175.3mg*\frac{1g}{1000mg}*\frac{1nol}{164g} }{1.50g*\frac{1kg}{1000g} } =0.713m[/tex]
In such a way, since the boiling point of pure chloroform is 61.2 °C, the boiling point of the solution is:
[tex]Tb=61.2\°C+1*0.713m*3.63\frac{\°C}{m} \\\\Tb=63.8\°C[/tex]
Regards.
Abigail obtained 36.6 grams of calcium carbonate after performing a reaction. From her calculations, she knew she should have obtained 44.1 grams. What was her percent yield
Answer:
it would be 1
Explanation:
A substance formed in a chemical reaction is called a
O A. reactant
B. equation
C. None of these
D. product
Answer: Product
Explanation:
A substance formed in a chemical reaction is called a products ,therefore option (d) is correct .
What do you mean by the chemical reaction ?A chemical reaction is a process that occurs when two or more molecules interact to form a new product(s).
Compounds that interact to produce new compounds are called reactants whereas the newly formed compounds are called products.
Products are substances that are created as a result of a chemical reaction. These products of reactions may be ions or molecules.
The result of a chemical reaction might exist in the solid, liquid, or gaseous phases.
A + B → C + D
Here,
A and B are the reactants, and
C and D are the products of their reaction.
A substance formed in a chemical reaction is called a products ,hence option (d) is correct .
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once energy is applyied to cause a object to vibrate a sound occours
Answer:
its true
Explanation:
Answer:
true
Explanation:
you stop on ground, ground vibrates and makes sound
The methane (CH4) molecule is tetrahedral, with each of the hydrogen atoms connected by a single bond to the central C atom. What type of orbital hybridization exists around the C atom
Answer:
The type of orbital hybridization around the C atom is sp3 hybridization.
Explanation:
The electron configuration of carbon is 1s² 2s² 2p². According to this configuration, carbon only has two semi-occupied orbitals that can form a covalent bond.
But a process called hybridization occurs, where the "s" and "p" orbitals at the (2s² 2p²) level combine and generate new orbitals. So this hybridization process where one "s" orbital is combined with three "p" orbitals forms four new sp³ hybrid orbitals (remember that there is 1 s orbital and 3 p orbitals for each layer or energy level). These four hybrid orbitals are half full, having only one electron and being capable of forming four covalent bonds.
So, the type of orbital hybridization around the C atom is sp³ hybridization.
True or false 12,785.000 has five significant digits.
Answer:
True
Explanation:
Significant digits include non-zero digits (unless the zero is between two non-zero numbers)
In 12,785.000, there are 5 non-zero digits:
1 2 7 8 5
ANSWER: the answer is true.
Which factor is least likely to cause a memory problem
The components that a cell can contain are (check all that apply)
Answer:
The components that a cell can contain are
nucleuscell membraneCytoplasmvacuolecell wallHow many moles are present 560.0 g of iron (lll) sulfate
Answer:
1.400 mol
Explanation:
To convert grams to moles, you will need the molar mass. The molar mass of iron(iii) sulfate is 399.88 g/mol. Divide grams by the molar mass to find moles.
(560.0 g)/(399.88 g/mol) = 1.400 mol
There are 1.400 mol present in 560.0 g of iron(iii) sulfate.
A student is using a coffee-cup calorimeter to determine the enthalpy change of the endothermic reaction of two aqueous solutions. After both solutions are added to the cup, the student neglects to put the lid on the cup. This would cause the magnitude of the calculated ΔH° value to be: the answer is: too small, since the solution will absorb heat from the room. But why? Wouldn't depend on if the reaction releases or absorbs heat. Wouldn't it be too large because heat escapes the cup? I'm so confused
Answer:
See the answer below
Explanation:
First, it should be understood that an endothermic reaction is one that absorbs energy in the form of heat from the surrounding. The products of endothermic reactions usually have higher energy than their reactants. Hence, the ΔH° which is referred to as the enthalpy change is usually positive.
Forgetting to cover the coffee-cup calorimeter means some of the heat energy absorbed by the reactants would be exchanged back to the surroundings - a loss. It also means that the enthalpy change would be smaller compared to if the cup had been covered because some of the heat has been lost to the surrounding.
The SI prefix kilo- indicates _____.
A. hundred
B. thousand
C. hundredth
D. thousandth
Answer:
b
Explanation:
The umbilicus in on the __ surface of the hand
Answer:
Umbilicus can't be on the hand....it is located in the abdomen....
The structure shown is represented of which sub
Answer:
Option B. pentan-1-ol
Explanation:
We'll begin by writing the name of the compound.
The name of the compound above is pentylpropanoate.
From the name of the compound and the structure, we can suggest the following equation:
CH3CH2COOH + HOCH2CH2CH2CH2CH3 —> CH3CH2COOCH2CH2CH2CH2CH3 + H2O
Thus,
Propanoic acid + pentan-1-ol —> pentylpropanoate + water.
Therefore, the alcohol used in the reaction is pentan-1-ol
If 801 J of heat is available, what is the mass in grams of iron (specific heat = 0.45 J/g･°C) that can be heated from 22.5°C to 120.0°C?
Answer:
The correct answer will be "18.25 g".
Explanation:
The given values are:
Specific heat,
C = 0.45 J/g･°C
Heat involved,
q = 801 J
Temperature,
ΔT = 120.0°C-22.5°C
= 97.5°C
As we know,
⇒ [tex]C = \frac{q}{m \Delta T}[/tex]
On substituting the given values, we get
⇒ [tex]0.45=\frac{801}{m(97.5)}[/tex]
⇒ [tex]m = 18.25 \ g[/tex]
The mass in grams of iron heated during the change in temperature is 18.26 grams.
Given the following data:
Initial temperature = 22.5°CFinal temperature = 120.0°CQuantity of heat = 801 JoulesSpecific heat capacity of iron = 0.45 J/g°C.To find the mass in grams of iron heated during the change in temperature:
Mathematically, quantity of heat is given by the formula;
[tex]Q = mc\theta[/tex]
Where:
Q represents the heat capacity or quantity of heat. m represents the mass of an object. c represents the specific heat capacity. ∅ represents the change in temperature.Making mass (m) the subject of formula, we have:
[tex]Mass = \frac{Q}{c \theta}[/tex]
Substituting into the formula, we have:
[tex]Mass = \frac{801}{0.45(120\;-\;22.5)} \\\\Mass = \frac{801}{0.45(97.5)} \\\\Mass = \frac{801}{43.875}[/tex]
Mass, m = 18.26 grams.
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consider a 1000-ml graduated cylinder with marks every 100 ml. a student records the volume of liquid in the cylinder as 750 ml. is this the correct measurement? explain
Answer:
Explanation:
The 1000-ml graduated cylinder with marks every 100 ml has least count of 100 ml . It means it can not measure a volume less than 100 ml . It can also measure volume in the integral multiple of 100 ml like 200 ml , 300 ml , 400 ml etc perfectly . All these have significant figure of one .
It can not measure volume like 150 , 250 , 255 , 760 etc because these measurements are not the integral multiple of 100 . 750 is not a integral multiple of 100 so it can not measure volume of 750 ml.
Barium chloride and sodium sulfate react according to the following equation. BaCl 2 + Na 2SO 4 → BaSO 4 + 2NaCl Answer the following question(s) about this reaction. How many grams of barium chloride are needed to make 100. grams of barium sulfate?
According to the stoichiometry and the given balanced chemical equation 89.22 g of barium chloride are needed to make 100 grams of barium sulfate.
What is stoichiometry?Stoichiometry is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining weights and volumes.
Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.
In the given chemical equation, 208.23 g of barium chloride produces 233.38 g of barium sulfate ,so for 100 g of barium sulfate 208.23×100/233.38 =89.22 g of barium chloride is required.
Thus, 89.22 g of barium chloride are needed to make 100 grams of barium sulfate.
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