Answer:
Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.
It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent, hence it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.
What is Dehydration ?A process such as a chemical reaction that removes water.The atoms which constitute the molecule of water that is removed.
Hence,It preferred to use calcium oxide rather than calcium chloride in preparation of iron (III) chloride because Calcium Oxide is a drying agent,
Thus, it dehydrates the reaction to give pure solid Iron ( III ) chloride, which cannot be done by calcium chloride.
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According to the equation 2K(s) + CI2(g) 2kCI(s), potassium reacts with chlorine to form potassium chlorine. If 100 atoms of potassium react with chlorine gas, how many chlorine molecules will be needed to completely react?
Answer:
50 CI₂ molecules
Explanation:
2K(s) + CI₂(g) → 2KCI(s)By looking at the stoichiometric coefficients, we can tell that if 2 atoms of potassium (K) react with chlorine gas (CI₂), 1 chlorine molecule would react.
With that in mind we can calculate how many CI₂ molecules would react with 100 K atoms:
100 atoms K *[tex]\frac{1Cl_2Molecule}{2KAtom}[/tex] = 50 CI₂ molecules2) If the density of chloroform is 1.48 g/mL, what is the volume of 541 g of chloroform?
Answer:
V = 365.54 mL
Explanation:
Given that,
The density of chloroform, d = 1.48 g/mL
The mass of chloroform, m = 541 g
We need to find the volume of chloroform.
We know that,
Density = mass/volume
So,
[tex]V=\dfrac{m}{d}\\\\V=\dfrac{541\ g}{1.48\ g/mL}\\\\=365.54\ mL[/tex]
So, the volume of chloroform is 365.54 mL.
The pH of a 0.1 M solution of an unknown weak acid is 3.7. What is the pKa of this acid?
Explanation:
Knowing the pH, you know the concentration of protons:
−log[H+]=pH=3.7
[H+]=10−3.7 M
Now, since the weak (monoprotic) acid dissociates into its conjugate base and a proton, the mols of protons are equimolar with the mols of conjugate base---the protons came FROM the weak acid, so the conjugate base that forms must be equimolar with the protons given out to the solvent.
HA⇌A−+H+
Hence, [A−]=[H+] in the same solution volume. Using the equilibrium constant expression, we get:
Ka=[H+]2eq[HA]eq
Don't forget that the HA form of HA had given away protons, so the mols of protons given away to generate A− is subtracted from the mols of (protons in) HA.
=[H+]2eq[HA]i−[H+]eq
=(10−3.7M)20.02M−10−3.7M
Ka=2.0105×10−6 M
If a light bulb has a voltage of 1.5 V and has 2.5A of current running through it, what is the resistance of the light bulb?
Answer:
0.6 ohm
Explanation:
voltage = 1.5 V
current = 2.5 A
resistence = ?
V = IR
1.5 = 2.5 * R
1.5 / 2.5 = r
0.6 = R
therefore resistence is 0.6 ohm
Which of the following statements is true?
A. Igneous rocks usually form in visible layers.
B. Metamorphic rocks are formed from eroded sediment
C. Sedimentary rocks form from cooling magma
D. The rock cycle recycles rock on Earth's surface.
Answer:
b
Explanation:
bc why not
The main consequence of exposure to the chemicals at Love Canal was:
allergies.
hair loss.
birth defects.
upper respiratory disease.
The main consequence of exposure to the chemicals at Love Canal was:
allergies.
hair loss.
birth defects.☑️upper respiratory disease.
The strongest base that can exist in a solution in appreciable concentration is the conjugate base of the solvent.
a. True
b. False
Answer:
a. True
Explanation:
From the basic concepts of acids and bases, we know that when a base accepts a hydrogen ion (H⁺), it forms a conjugate acid which can accept again the H⁺ ion:
B⁻ + H₂O ⇆ BH + OH⁻
The stronger the base, the weaker the conjugate base. Thus, as more strength has a base, lesser strength will have the conjugate base (it will not be able to accept again the H⁺ ion). For example, when water (H₂O) loses its H⁺ , it forms the conjugate base OH⁻. So, OH⁻ is the stronger base that can exist in an aqueous solution.
H₂O ⇆ H⁺ + OH⁻
In fact, strong bases are hydroxides, such as NaOH or KOH.
Project: Global Temperature Change
Research and write an essay about the rise of global temperatures over the past century.
PLEASE HELP THIS IS 10% OF MY GRADE
Answer:
Im sorry i cant write a whole essay right now but these sourcea could help.
https://climate.nasa.gov/effects/
https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature
Answer:
have you done it yet?
Explanation:
..
Determine whether each description relates to wavelength or frequency.
a. Increases as energy decreases
b. Often measured in units such as nanometers (nm)
c. Often measured in units such as Hertz (Hz)
d. Increases as energy increases
e. A measure of cycles per unit time
f. A measure of distance
g. Frequency Wavelength
Answer:
Wavelength
a. Increases as energy decreases
b. Often measured in units such as nanometers (nm)
f. A measure of distance
Frequency
c. Often measured in units such as Hertz (Hz)
d. Increases as energy increases
e. A measure of cycles per unit time
Explanation:
Wavelength increases when the energy decreases whereas frequency increases as energy increases. Wavelength is measured in nanometers (nm) whereas frequency is measured in hertz. Frequency refers to the number of cycles in a unit of time while on the other hand, the distance between successive crests of a wave, especially in a sound wave or electromagnetic wave is known as wavelength.
Jax designs an experiment to determine how the amount of sodium chloride affects the boiling point of water. He adds 1 g, 5 g, and 10 g of sodium chloride to three different beakers, each containing 100 mL of water. There is a fourth beaker that contains 100 mL water without any sodium chloride. He heats each of the samples on a Bunsen burner and measures the boiling point with the same thermometer. Which of the following is/are the control(s) in the experiment? (Choose all that apply)
Answer:
Amount of water
The thermometer
Explanation
In an experiment, there is always a dependent variable and an independent variable. The independent variable is manipulated and its effect on the dependent variable is observed.
The control is that factor in the experiment that must remain constant so that effect of the independent variable on the dependent variable can be observed.
In this case, the independent variable is the amount of sodium chloride while the dependent variable is the temperature at which the solution boils.
The controls must be the amount of water which must be held constant and the same thermometer used to measure the temperature so that the effect of the amount of sodium chloride on the temperature of the solution can be studied.
The following are the controls in the experiment:
The beaker with 100 mL of water without any sodium chloride.
The temperature of the Bunsen burner.
The type of thermometer used.
The control(s) in the experiment are the beaker with 100 mL of water without any sodium chloride. This beaker is used to compare the boiling points of the other beakers, which have different amounts of sodium chloride added.
The control beaker ensures that any differences in boiling point are due to the amount of sodium chloride added, and not to other factors, such as the temperature of the Bunsen burner or the type of thermometer used.
The other factors that could affect the boiling point of water, such as the humidity of the air or the altitude, are kept constant in the experiment.
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A series of measurements in the lab led to an experimental result of 32.9 mL, with a calculated standard deviation of 0.3 mL. What is the standard way to report this result?
Answer: The standard way to report this result is [tex]32.9\pm 0.3 mL[/tex]
Explanation:
The standard method of representing a result is:
[tex]\text{Calculated value }\pm \text{ Standard deviation}[/tex]
The reporting of a result is done in correct significant figures.
We are given:
Calculated value = 32.9 mL
Standard deviation = 0.3 mL
Rule of significant figures applied when numbers are added or subtracted:
The number having less number of significant figures after the decimal point will determine the number of significant figures in the final answer.
Number of significant figures after the decimal point = 1
Hence, the standard way to report this result is [tex]32.9\pm 0.3 mL[/tex]
What are some of the reasons why the United States did not adopt the metric system of measure?
at the time most of its trade was with France who did not use the metric system
the House of Representatives defeated the bill calling for conversion to metrics in 1974
the US was waiting for all other industrialized countries to adopt it before proceeding
at the time most of its trade was with England and Canada who did not use the metric system
Answer: in 1975, the United States passed the Metric Conversion Act. The legislation was meant to slowly transition its units of measurement from feet and pounds to meters and kilograms, bringing the US up to speed with the rest of the world. There was only one issue: the law was completely voluntary. Of course, that meant it pretty much never took off
Explanation:
they passed the metric act
How many milliliters of a 0.40%(w/v) solution of nalorphine must be injected to obtain a dose of 1.5 mg?
Answer:
0.375mL of solution of nalorphine must be injected
Explanation:
A solution of 0.40% (w/v) contains 0.40g of solute (In this case, nalorphine), in 100mL of solution. To obtain 1.5mg of nalorphine = 1.5x10⁻³g of nalorphine are needed:
1.5x10⁻³g * (100mL / 0.40g) =
0.375mL of solution of nalorphine must be injectedwhy is platinum metal preferred to other metals for the flame test
Answer:
Platinum is especially good for this because it is unreactive, and does not produce a color in the flame which will mask the presence of other metals.
Hope this answer is right!
Answer:
Hey mate, here is your answer
1. Platinum doesn't impart any color to the flame.
2. It is not oxidised under the high temperature of the flame from a bunsen burner.
3. It is almost chemically inert. Even at high temperatures, it remains unattacked by free radicals / acid radicals.
Therefore, platinum wire is crucial for a flame test. Also, a platinum wire should be thoroughly cleaned before using it for a new flame test.
A platinum wire is cleaned by dipping it into concentrated HNO3 and then placing it in the non luminous part of the bunsen flame. Otherwise, the perviously tested radicals will impart color to the flame, which may cause confusion.
Explanation:
Hope it helps you
At 900 oC, Kp = 1.04 for the reactionCaCO31(s) arrow CaO (s) + CO2 (g)At a low temperature, dry ice (solid CO2), calcium oxide, and calcium carbonate are introduced into a 50.0-L reaction chamber. The temperature is raised to 900 oC, resulting in the dry ice converting to gaseous CO2. For the following mixtures, will the initial amount of calcium oxide increase, decrease, or remain the same as the system moves toward equilibrium at 9000 oC?a. 655 gCaCO3, 95.0 gCaO, PCO2 = 2.55 atm.b. 780 gCaCO3, 1.00 gCaO, PCO2 = 1.o4 atm.c. 0.14 gCaCO3, 5000 gCaO,PCO2 = 1.04 atm.d. 715 gCaCO3, 813 gCaO, PCO2 = 0.211 atm.
Answer:
a)the reaction will proceed to the left, the mass of CaO will decrease.
b)the reaction is in equilibrium, mass of CaO will not change.
c)the reaction is in equilibrium, mass of CaO will not change.
d) the reaction will proceed to the right, the mass of CaO will increase.
Explanation:
Step 1: Data given
At 900°C, Kp = 1.04 ( Kp is only for compounds that are in gaseous state)
Volume of the chamber = 50.0L
Temperature is raised to 900 °C
Step 2: The reaction
CaCO31(s) ⇔ CaO (s) + CO2 (g)
Kp for CO2 = 1.04
Step 3: First mix : 655g CaCO3, 95.0g CaO, PCO2 = 2.55 atm
We only consider CO2 here
pCO2 > Kp this means the reaction will proceed to the left, the mass of CaO will decrease.
Step 4: 780g CaCO3, 1.00g CaO, PCO2 = 1.04 atm.
We only consider CO2 here
pCO2 = Kp this means the reaction is in equilibrium, mass of CaO will not change.
Step 5: 0.14g CaCO3, 5000g CaO, PCO2 = 1.04 atm
We only consider CO2 here
pCO2 = Kp this means the reaction is in equilibrium, mass of CaO will not change.
Step 6: 715g CaCO3, 813g CaO, PCO2 = 0.211 atm
We only consider CO2 here
pCO2 < Kp this means the reaction will proceed to the right, the mass of CaO will increase.
What is the observation of heating of iodine crystals
Answer:
On heating, the van der Waals dispersion forces existing then will easily break as it has a low boiling point and sublimates into gas. On heating iodine in the test tube, iodine evolves as violet fuming gas.
Explanation:
ACTUAL YIELD VS THEORETICAL YIELD?
Actual yield over theoretical yield, then multiply by 100
D. Write the name of the branched alkane next to the drawing of the molecule. (2 points)
Answer: hello your question lacks some data attached below is the missing data
answer :
a) 3-methyl heptane
b) 2-methyl pentane
c) 2-methyl heptane
d) 2-methyl hexane
e) 3-methyl hexane
Explanation:
we will select the longest carbon chain as the branched alkane and name it
a) 3-methyl heptane ( first diagram )
b) 2-methyl pentane ( second diagram )
c) 2-methyl heptane ( third diagram )
d) 2-methyl hexane ( fourth diagram )
e) 3-methyl hexane ( fifth diagram )
Note : sixth diagram = first diagram
Please help quick thanks
Answer:
Q = 6019J
Explanation:
Using the formula as follows:
Q = m × c × ∆T
Where;
c = specific heat capacity
Q = amount of heat (J)
m = mass of substance
∆T = change in temperature (°C)
According to the information given in this question,
m = 80g
c = 4.18 J/g°C
Initial temperature = 25°C
Final temperature = 43°C
∆T = 43°C - 25°C = 18°C
Q = 80 × 4.18 × 18
Q = 6019.2J
what two parts are needed to make a neutral atom of neon
Answer:
it needs two electrons in the first and eight to fill the second.
Explanation:
Because neon has two atomic shells, it needs two electrons in the first and eight to fill the second. Neon has a total of ten electrons which means two filled shells.
Calculate and compare the number of ATP molecules generated between a 24 carbon fatty acid and 4 glucose molecules.
Answer:
Idont no men sorry idont understand
Explanation:
Sorry
in a reaction 2Fe+Cl2→2FeCl2
Answer:
no equation
Explanation:
Liquid hexane
(CH,(CH), CH) will react with gaseous oxygen (0) to produce gaseous carbon dioxide (CO2) and gaseous water (1,0). Suppose 1.72 g
of hexane is mixed with 8.0 g of oxygen. Calculate the maximum mass of water that could be produced by the chemical reaction. Be sure your answer has the
correct number of significant digits.
Answer: The mass of [tex]H_2O[/tex] produced is 2.52 g
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
For hexane:Given mass of hexane = 1.72 g
Molar mass of hexane = 86.18 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of hexane}=\frac{1.72g}{86.18g/mol}=0.020mol[/tex]
For oxygen gas:Given mass of oxygen gas = 8.0 g
Molar mass of oxygen gas= 32 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of water}=\frac{8.0g}{32g/mol}=0.25mol[/tex]
The chemical equation for the combustion of hexane follows:
[tex]2C_6H_{14}+19O_2\rightarrow 12CO_2+14H_2O[/tex]
By stoichiometry of the reaction:
If 2 moles of hexane reacts with 19 moles of oxygen gas
So, 0.020 moles of hexane will react with = [tex]\frac{19}{2}\times 0.020=0.19mol[/tex] of oxygen gas
As the given amount of oxygen gas is more than the required amount. Thus, it is present in excess and is considered as an excess reagent.
Thus, hexane is considered a limiting reagent because it limits the formation of the product.
By the stoichiometry of the reaction:
If 2 moles of hexane produces 14 moles of [tex]H_2O[/tex]
So, 0.020 moles of hexane will produce = [tex]\frac{14}{2}\times 0.020=0.14mol[/tex] of [tex]H_2O[/tex]
We know, molar mass of [tex]H_2O[/tex] = 18 g/mol
Putting values in above equation, we get:
[tex]\text{Mass of }H_2O=(0.14mol\times 18g/mol)=2.52g[/tex]
Hence, the mass of [tex]H_2O[/tex] produced is 2.52 g
Balancea las siguientes ecuaciones por el método de redox. Determina el
agente oxidante, el agente reductor, la sustancias oxidada y la sustancia
reducida para cada caso.
a) C + H2SO4
CO2 + SO2 + H2O
I
b) sh + HNO3
Sb2O5 +NO + H2O
c) Bi(OH)3 +K SnO2
Bi + K Sn03
+ H2O
d) H2S + (Cr2O7)2- + H1+
H2O + S + Cr3+
Answer:
Traduzca al ingles para que pueda responder a su pregunta. Te dare la reapuesta en los comentarios
Which of the following amino acid residues would provide a side chain capable of increasing the hydrophobicity of a binding site?
A) aspartic acid
B) lysine
C) isoleucine
D) arginine
E) serine
Answer:
C) isoleucine
Explanation:
Isoleucine is among nine necessary amino acids in humans (found in dietary proteins). It has a variety of physiological activities, including aiding tissue repair, nitrogenous waste detoxification, immunological stimulation, and hormonal production promotion. When attached at a binding site, they are capable of providing a side chain thereby increasing the hydrophobicity at the binding site.
The theoretical yield of zinc oxide in a reaction is 486 g. What is the percent
yield if 399 g is produced?
O A. 122%
O B. 4.93%
C. 82.1%
D. 29.6%
Answer:
the correct answer is c
Explanation:
becuase i had the same question
an element E forms a hydride EH3, which contains 90% of E by mass. what is the relative atomic mass ?
Answer:
27 g/mol of E
Explanation:
Note that percentage by mass= mass of each element present. So, since there is 90% of E, there is 90g of E present. By implication, there are 10g of H corresponding to 10%H. Note that there is 100g of EH3
1 moles of E corresponds to 90 g of E
Mole ratio of E: H= 1:3
Thus
Number of moles of H = 10g/ 1g/ mol = 10 moles of H
Since E contains 1/3 the number of moles of H
Number of moles of E = 1/3 × 10 = 3.33 moles of E
Molar mass of E= mass of E/ number of moles of E
Since mass of E = 90 g
Molar mass of E = 90g/3.33 moles
Molar mass of E = 27 g/mol
In a 0.730 M solution, a weak acid is 12.5% dissociated. Calculate Ka of the acid.
Answer:
Approximately [tex]1.30 \times 10^{-2}[/tex], assuming that this acid is monoprotic.
Explanation:
Assume that this acid is monoprotic. Let [tex]\rm HA[/tex] denote this acid.
[tex]\rm HA \rightleftharpoons H^{+} + A^{-}[/tex].
Initial concentration of [tex]\rm HA[/tex] without any dissociation:
[tex][{\rm HA}] = 0.730\; \rm mol \cdot L^{-1}[/tex].
After [tex]12.5\%[/tex] of that was dissociated, the concentration of both [tex]\rm H^{+}[/tex] and [tex]\rm A^{-}[/tex] (conjugate base of this acid) would become:
[tex]12.5\% \times 0.730\; \rm mol \cdot L^{-1} = 0.09125\; \rm mol \cdot L^{-1}[/tex].
Concentration of [tex]\rm HA[/tex] in the solution after dissociation:
[tex](1 - 12.5\%) \times 0.730\; \rm mol \cdot L^{-1} = 0.63875\; \rm mol\cdot L^{-1}[/tex].
Let [tex][{\rm HA}][/tex], [tex][{\rm H}^{+}][/tex], and [tex][{\rm A}^{-}][/tex] denote the concentration (in [tex]\rm mol \cdot L^{-1}[/tex] or [tex]\rm M[/tex]) of the corresponding species at equilibrium. Calculate the acid dissociation constant [tex]K_{\rm a}[/tex] for [tex]\rm HA[/tex], under the assumption that this acid is monoprotic:
[tex]\begin{aligned}K_{\rm a} &= \frac{[{\rm H}^{+}] \cdot [{\rm A}^{-}]}{[{\rm HA}]} \\ &= \frac{(0.09125\; \rm mol \cdot L^{-1}) \times (0.09125\; \rm mol \cdot L^{-1})}{0.63875\; \rm mol \cdot L^{-1}}\\[0.5em]&\approx 1.30 \times 10^{-2} \end{aligned}[/tex].
Question 3 (2 points)
Using the following equation how many grams of water you would get from 846 g of
glucose:
C6H12O6 + 602 + 6CO2 + 6H20 + energy
Your Answer:
Answer
units g)
Answer: The mass of water produced is 507.6 g
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
Given mass of glucose = 846 g
Molar mass of glucose = 180 g/mol
Plugging values in equation 1:
[tex]\text{Moles of glucose}=\frac{846g}{180g/mol}=4.7 mol[/tex]
The given chemical equation follows:
[tex]C_6H_{12}O_6+6O_2\rightarrow 6CO_2+6H_2O+energy[/tex]
By the stoichiometry of the reaction:
If 1 mole of glucose produces 6 moles of water
So, 4.7 moles of glucose will produce = [tex]\frac{6}{1}\times 4.7=28.2mol[/tex] of water
Molar mass of water = 18 g/mol
Plugging values in equation 1:
[tex]\text{Mass of water}=(28.2mol\times 18g/mol)=507.6g[/tex]
Hence, the mass of water produced is 507.6 g
A 8.29g sample of calcium sulfide was decomposed into its constituent elements, producing 4.61g of calcium and 3.68g of sulfur. Which of the statements are consistent with the law of constant composition (definite proportions)?
a. Every sample of calcium sulfide will have 44.4% mass of calcium.
b. Every sample of calcium sulfide will have 2.86 g of calcium.
c. The mass ratio of Ca to S in every sample of calcium sulfide is 1.25.
d. The ratio of calcium to sulfur will vary based on how the sample was prepared.
e. The mass percentage of calcium plus the mass percentage of sulfur in every sample of calcium sulfide equals 100%.
Answer:
d,e
Explanation: