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:
Determine the molality and molarity of a sodium chloride solution prepared by adding 52.80 g of solid NaCl to 150.0 g of water. The density of the saline solution is 1.1972 g mL . Molality
Answer:
6.02 m5.334 MExplanation:
First we convert 52.80 g of NaCl to moles, using its molar mass:
52.80 g ÷ 58.44 g/mol = 0.9035 molTo determine the molality, we convert 150.0 g of water to kg:
150.0 g / 1000 = 0.150 kgmolality = 0.9035 mol / 0.150 kg = 6.02 mAs for the molarity, we determine the total mass of solution:
52.80 g + 150.0 g = 202.8 gAnd calculate the volume, using the density:
202.8 g ÷ 1.1972 g/mL = 169.39 mL169.39 mL / 1000 = 0.16939 LFinally we calculate the molarity:
0.9035 mol / 0.16939 L = 5.334 Man 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
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
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 injectedACTUAL YIELD VS THEORETICAL YIELD?
Actual yield over theoretical yield, then multiply by 100
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
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
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 moleculesCalculate 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
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.
The volume of a fixed mass of gas at 2 atm pressure is 20L.What will be its volume if the pressure is increased 4 times without changing the temperature.
Answer:
The correct answer is - 5L.
Explanation:
From the ideal gas equation -
pv=nRT
p = pressure
v =volume
Here nRT is constant so
P would be inversely proportioned to v
So, p1/p2 = v2/v1
Putting values:
2/4(2) = v2/20 (p2 = 4 times of P1)
2/8 = v2/20
V2 = 5
Thus, the correct volume at new pressure would be - 5 L.
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
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.
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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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.
If 7.90 mol of C5H12 reacts with excess O2, how many moles of CO2 will be produced by the following combustion reaction?
C5H12+8O2=6H2O+5CO2
Answer:
moles CO₂ produced from combustion of 7.9 mole of C₅H₁₂ = 39.5 moles CO₂
Explanation:
C₅H₁₂ + 8O₂ => 6H₂O + 5CO₂
Given: 7.9moles excess _____ ? moles
From Equation, 1 mole C₅H₁₂ =============> 5 moles CO₂
Given 7.9 mole C₅H₁₂ =============> X
Solving for 'X' using ratio and proportion ...
1mole C₅H₁₂ / 7.9mole C₅H₁₂ = 5mole CO₂ / X
=> X = 5 mole CO₂ x 7.9mole C₅H₁₂ / 1mole C₅H₁₂ = 39.5 moles CO₂
≅ 40 moles CO₂ (2 sig. figs.)
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
Question 1
Consider the following reaction:
Cl2(g) + 3 F2(g) —> 2 CIF3 (8)
How many moles of product will form if 0.115 moles of fluorine gas react?
Answer:
0.077 mole of ClF₃.
Explanation:
The balanced equation for the reaction is given below:
Cl₂ + 3F₂ —> 2ClF₃
From the balanced equation above,
3 moles of F₂ reacted to produce 2 moles of ClF₃.
Finally, we shall determine the number of mole of ClF₃ produced by the reaction of 0.115 mole of F₂. This can be obtained as follow:
From the balanced equation above,
3 moles of F₂ reacted to produce 2 moles of ClF₃.
Therefore, 0.115 mole of F₂ will react to to produce = (0.115 × 2)/3 = 0.077 mole of ClF₃.
Thus, 0.077 mole of ClF₃ was obtained from the reaction.
in a reaction 2Fe+Cl2→2FeCl2
Answer:
no equation
Explanation:
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].
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.
Which of the following reasons explains why if salt water is heated, the water turns into steam while the salt remains?
Water and salt have an equal boiling point.
Water has a lower boiling point than salt.
Salt has a lower boiling point than water.
Salt and water have an equal melting point.
If the salt water is heated, the water turns into steam and the salt remains because the water has a lower boiling point than the salt.
The following points can be considered:
The boiling point is defined as the temperature at which the substance turns into the gaseous state from the liquid state.The boiling point of water is [tex]100^{o} C[/tex].The salt is a substance comprising two entities separated by the opposite charges with ionic interactions.The boiling point of a salt is higher than the boiling point of the water.The process involved when salt water is heated:
The salt water mixture when heated, the water turns into steam at [tex]100^{o} C[/tex]But the salt remains until it reaches its boiling temperature. If the salt is soluble in water and is then heated, then there occurs an elevation in the boiling point of the substance, due to the presence of the salt.Therefore, the answer is water has a lower boiling point than salt.
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why 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
Groups on the periodic table also correspond with the number of ?
The question is incomplete, the complete question is;
Groups of the periodic table correspond to elements with a. the same color b. the same atomic number c. similar chemical properties d. similar numbers of neutrons
Answer:
similar chemical properties
Explanation:
In the periodic classification of elements, elements are divided into groups and periods. Elements in the same group of the periodic table have the same number of outermost electrons and share very similar chemical properties.
Elements in the same period have the same number of shells and the same maximum energy level of the outermost electron. Chemical properties carry markedly across a period.
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:
Classification of igneous, sedimentary and metamorphic rocks is based on
A)Mineral assemblages and composition assemblages and composition
B)Appearance of the rock and texture
C)composition and mineral make-up
D)Texture and rock chemistry
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.
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
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