Answer:
Số gam muối ăn cần là 76:42,7%=177,986 g
Explanation:
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.
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
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:
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
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
in a reaction 2Fe+Cl2→2FeCl2
Answer:
no equation
Explanation:
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
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
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
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 moleculesACTUAL YIELD VS THEORETICAL YIELD?
Actual yield over theoretical yield, then multiply by 100
2) 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.
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.
Type the correct answer in the box.
Calculate the density of the substance.
A sample of a substance has a mass of 27.3 grams and a volume of 7.0 centimeters3. The density of this substance is ____
grams/centimeter3.
Answer:
3.9g/cm3
Explanation:
Density ( d)=?
Mass(m)=27.3g
Volume (v)=7.0cm3
D=m÷v
D=27.3g÷7.0cm3
D=3.9g/cm3
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.
What happens to the concentration of hydron What happens to the pH of a buffer when a small amount of acid is added? It will decrease by 10 points. It will increase by 10 points. It will stay about the same.ium ions as the pH of a solution increases? Disabled A. hydronium ion concentration increases Student Selected Incorrect B. hydronium ion concentration stays the same Disabled C. hydronium ion concentration decreases
Answer:
B
Explanation:
the concentration will be the same disabled
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
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:
..
What mass of hydrochloric acid that reacted with zinc will produced 0.15dm3 of hydrogen at st.p? Equation for this reaction:
Zn + 2HCl ------> ZnCl2 + H2
Answer:
[tex]{ \tt{22.4 \: dm {}^{3} \: contains \: 1 \: mole \: of \: hydrogen }} \\ { \tt{0.15 \: {dm}^{3} \: will \: contain \: ( \frac{0.15}{22.4} \times 1) \: moles }} \\ = 0.0067 \: moles \\ { \bf{mole \: ratio = 1 :1 }} \\ { \tt{1 \: mole \: weighs \: 65.38 \: g}} \\ { \tt{0.0067 \: moles \: weighs \: (0.0067 \times 65.38) \: g}} \\ = 0.44 \: g[/tex]
5. What, if anything, is wrong with the nuclear equation shown below?
O
179
179 W
+
e
Re
-1
75
74
O A. The daughter product has the wrong atomic number.
O B. The daughter product has the wrong mass number
O c. The particle labeled 'e should have an mass number of 1.
O D. There is nothing wrong with the equation.
Answer:
It is A, The daughter product has the wrong atomic number
Explanation:
Have trust, please i beg of you.
:) thank me later, love ya
The daughter's product has the wrong atomic number. Hence, option A is correct.
What is the nuclear equation?Nuclear equations represent the reactants and products in radioactive decay, nuclear fission, or nuclear fusion.
Beta decay - A common mode of radioactive decay in which a nucleus emits beta particles. The daughter nucleus will have a higher atomic number than the original nucleus.
Hence, the daughter's product has the wrong atomic number.
Learn more about nuclear equation here:
https://brainly.com/question/20660529
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Which type of chemistry studies the chemical reactions that occur in the human body?
O biochemistry
O materials chemistry
O physical chemistry
O environmental chemistry
Answer:
Which type of chemistry studies the chemical reactions that occur in the human body? .
biochemistry
The correct answer is biochemistry.
What is Biochemistry?Biochemistry is the study of the chemical process that occur in living things.Why other Options are incorrect?Materials Chemistry is the section of Materials Science and Engineering that investigates the chemical nature of materials.Physical chemistry is the branch of chemistry that deals with physical structure of chemical compound. Environmental chemistry is the study of chemical process that deals with environment.
Learn more about Biochemistry here
https://brainly.com/question/13128204
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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
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.
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]
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 injectedusing standard reduction potentials
Cr+3e = Cr -0.4 volt
Cl2+2e = 2Cl +1.36 volt
what the value of E for the cell with reaction
2Cr +3Cl2 = 3Cr +6Cl
Answer:
Hindi ko Po alam sorry po
For the neutralization reaction between pyridine and propanoic acid, draw curved arrows to indicate the direction of electron flow. Draw curved arrows to show the movement of electrons in this step of the mechanism.
Answer:
For the neutralization reaction between pyridine and propanoic acid, draw curved arrows to indicate the direction of electron flow.
Draw curved arrows to show the movement of electrons in this step of the mechanism.
Explanation:
According to Bronsted acid-base theory, an acid is a substance which is a proton donor.
Base is the proton acceptor.
In the given example, acid is propanoic acid and it loses the proton.
Pyridine is the base and it accepts the proton from propanoic acid.
The entire reaction is shown below:
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.
Please help me with question 7. Thank you so much.
Answer:
The system is not at equilibrium and the reaction will proceed to the left.
Explanation:
Step 1: Write the balanced equation
H₂(g) + CO₂(g) ⇄ CO(g) + H₂O(g)
Step 2: Calculate the reaction quotient (Q)
The reaction is calculated in the same way as the equilibrium constant (Kc) but it uses the concentrations at any time.
Q = [CO] × [H₂O] / [H₂] × [CO₂]
Q = 0.610 × 0.695 / 0.425 × 0.500 = 2.00
Since Q ≠ Kc, the reaction is not at equilibrium.
Since Q > Kc, the reaction will proceed to the left.