Answer:
a. 2.5 g
b. 0.025
c. i. 10 times ii 25 g of KI
Explanation:
a. A 2.5% (by mass) solution concentration signifies that there is ______ of solute in every 100 g
Since % by mass = mass of solute, m/mass of solvent,M × 100 %
2.5 % = m/M × 100%
since M = 100 g,
2.5 % = m/100 × 100 %
m/100 = 2.5/100
m = 2.5 g
b. Therefore, when 2.5% is expressed as a ratio of solute mass over solution mass, that mass ratio would be ________
The mass ratio = mass of solute/mass of solvent
= m/M
= 2.5 g/100 g
= 0.025
c A solution mass of 1 kg is _______ times greater than 100 g, thus one kilogram (1 kg) of a 2.5% KI solution would contain ____________of
i. A solution mass of 1 kg is _______ times greater than 100 g
Since 1 kg = 1000 g, 1 kg/100 g = 1000 g/100 g = 10
So,1 kg is 10 times greater than 100 g.
ii. Thus one kilogram (1 kg) of a 2.5% KI solution would contain ____________of KI
So, if M = 1 kg = 1000 g, we find m
Since % by mass = mass of solute, m/mass of solvent,M × 100 %
2.5 % = m/M × 100%
since M = 1000 g,
2.5 % = m/1000 × 100 %
m/1000 = 2.5/100
m = 2.5/100 × 1000 g
m = 2.5 × 10 g
m = 25 g
0=4
Balance this equation
H₂sicl2+ H₂O → H8Si4O4 + HCl
Balanced Equation is
4H2SiCl2+4H2O → H8Si4O4 + 8HCl
Chemical bond stretching frequencies depend on two major factors, namely atomic weight and bond stiffness. The frequency absorbed is directly proportional to the bond strength (stiffness) but inversely proportional to the atomic weight. Which of the following bonds will give the highest absorption frequency value?
A. C single bond C.
B. C double bond C.
C. All would be the same frequency.
D. C triple bond C.
Answer:
D. C triple bond C.
Explanation:
The absorption frequency value is highest for carbon-carbon triple bond. The stretching frequencies are much higher than the bending frequency. It mainly depends upon the strength of the bonds as well as masses of the bonded atoms.
The triple bonds have higher stretching strength than the double bonds and double bonds have higher strength than single carbon to carbon bonds.
The triple bonds has a higher bond order, i.e. 3. So it has maximum stretching bonds.
n-hexane boils at 68.7 oC at 1.013 bar and the heat of Vaporization is 28850
J/mol. Calculate Its Entropy ?
What is the function of a
catalyst?
A. Build enzymes
B. Speed up chemical reactions
C. Regulate the function of an enzyme
I believe it is to speed up chemical reactions
Atomic number: 19 is what Chemical symbol?
Answer:
oficialismo hemostasia Jalisco
Answer:
K
Explanation:
Potassium is atomic no 19 and it is k because is from kalium, the Meldiaeval Latin for potash, which may have derived from an arabic word quality, meaning alkali.
Atomic mass, 39.098amu
Oxidation status, +1
Year discovered, 1807
Melting point, 63.28 degrees Celsius(145.90degrees Fahrenheit )
Boiling point, 760 degrees Celsius (1400 degrees Fahrenheit )
What mass of sucrose is needed to make 300.0 mL of a 0.5 M solution? (molar mass=
342.34 g/mol)
A silver bar with a specific heat of 0.235J/gºC has a mass of 250.g and is heated from 22.0°C to 68.5°C. How much heat will the silver bar absorb?
Answer:
2731.875 J
Explanation:
Applying
Q = cm(t₂-t₁)................ Equation 1
Where Q = amount of heat, c = specific heat capacity of silver, m = mass of silver, t₂ = Final temperature of silver, t₁ = Initial temperature of silver
From the question,
Given: c = 0.235 J/g°C, m = 250 g, t₁ = 22.0°C, t₂ = 68.5°C
Substitute these values into equation 1
Q = 0.235×250(68.5-22.0)
Q = 58.75(46.5)
Q = 2731.875 J
If a drop of red dye is placed in the middle of a shallow dish of water, the dye will diffuse slowly and a red cloud of dye will grow larger with time.
a. True
b. False
Answer:
True
Explanation:
Diffusion is the movement of the particles of a substances from a region of higher concentration to a region of lower concentration.
Diffusion occurs in response to a concentration gradient.
In this case, the dye is at a higher concentration at the middle of the shallow dish of water. Diffusion causes the dye to spread out gradually thereby causing the red cloud to grow larger with time.
What is the new volume of a 61 L sample at STP that is moved to 183 K and 0.60 atm?
Answer: The new volume of a 61 L sample at STP that is moved to 183 K and 0.60 atm is 54.63 L.
Explanation:
Given: [tex]V_{1}[/tex] = 61 L, [tex]T_{1}[/tex] = 183 K, [tex]P_{1}[/tex] = 0.60 atm
At STP, the value of pressure is 1 atm and temperature is 273.15 K.
Now, formula used to calculate the new volume is as follows.
[tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}[/tex]
Substitute the values into above formula as follows.
[tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}\\\frac{0.60 atm \times 61 L}{183 K} = \frac{1 atm \times V_{2}}{273.15 K}\\V_{2} = 54.63 L[/tex]
Thus, we can conclude that the new volume of a 61 L sample at STP that is moved to 183 K and 0.60 atm is 54.63 L.
If the plant population decreased, the amount of carbon in the atmosphere would _______.
Increase
Stay the same
Decrease
Answer:
increase answer
Explanation:
i hope that is right
Estimate the volume of a solution of 5M NaOH that must be added to adjust the pH from 4 to 9 in 100 mL of a 100 mM solution of a phosphoric acid?
Answer:
3mL of 5M NaOH must be added to adjust the pH to 7.20
Explanation:
When NaOH is added to phosphoric acid, H₃PO₄, the reaction that occurs are:
NaOH + H₃PO₄ ⇄ NaH₂PO₄ + H₂O pKa1 = 2.15
NaOH + NaH₂PO₄ ⇄ Na₂HPO₄ + H₂O pKa2 = 7.20
NaOH + Na₂HPO₄ ⇄ Na₃PO₄ + H₂O pKa3 = 12.38
We can adjust the pH at 7.20 = pKa2 if NaH₂PO₄ = Na₂HPO₄. To make that, we must convert, as first, all H₃PO₄ to NaH₂PO₄ and the half of NaH₂PO₄ to Na₂HPO₄. To solve this question we need to find the moles of phophoric acid in the initial solution. 1.5 times these moles are the moles of NaOH that must be added to fix the pH to 7.20:
Moles H₃PO₄:
100mL = 0.100L * (0.100mol / L) = 0.0100 moles H₃PO₄
Moles NaOH:
0.0100 moles H₃PO₄ * 1.5 = 0.0150 moles NaOH
Volume NaOH:
0.0150 moles NaOH * (1L / 5moles) = 3x10⁻³L 5M NaOH are required =
3mL of 5M NaOH must be added to adjust the pH to 7.203 mL of 5 Molar NaOH is required to adjust the pH of phosphoric acid.
What is pH?It is the negative log of the concentration of Hydrogen ions in the solution.
To calculate the volume of NaOH first, calculate the moles of NaOH and H₃PO₄.
Moles of H₃PO₄.
[tex]\rm moles \ of \ H_3PO_4 = 100\rm \ mL = 0.100\rm \ L \times (0.100 \ mol / L)\\\\\rm moles \ of \ H_3PO_4 = 0.01[/tex]
The moles of NaOH:
[tex]\rm Moles \ of \ NaOH =0.01 \ moles \ H_3PO_4\times 1.5 \\\\\rm Moles \ of \ NaOH= 0.0150[/tex]
The volume of NaOH:
[tex]\rm Volume\ of \ NaOH = \rm 0.0150\ moles\ NaOH \times (1 \ L / 5 \ moles) \\\\\rm Volume\ of \ NaOH = 3\times 10^{-3} L[/tex]
Therefore, 3 mL of 5 Molar NaOH is required to adjust the pH of phosphoric acid.
Learn more about pH:
https://brainly.com/question/3262317
What causes the recognition of an element from its energy signature?
O
A. Each element emits radiations at random frequencies.
B. Each element emits energy that can be transformed into sound.
C. Each element emits electromagnetic waves that travel faster than light.
D. Each element emits electromagnetic waves at a unique set of wavelengths.
Answer:
I'm so sorry if this is wrong but I think its B
when 18.0 g H20 is mixed with 33.5 g Fe, which is the limiting reactant?
Answer:
si.mple fe
Explanation:
ghhsshzhzbbzhh
the mass in g of 3 moles Al .
Answer:
81 gm
Explanation:
The mass of 1 mole is 27 g
So, Mass of 3 moles of Aluminium would be 3 × 27 = 81 gm..Thus mass of 3 Moles of Aluminium is 81 gm.
Which of the following
describes the zone of the
ocean where no light reaches?
A. up to 200 meter depth and includes
photosynthetic plants, sea anemones,
sponges, crabs, and clams
B. the "twilight zone" between 200-1000
meters deep and includes whales and octopi
and little life
C. permanent darkness below 1000 meters
with bioluminescent bacteria, bottom
feeders, and angler fish
Answer:
Bathypelagic
54% of the ocean lies in the Bathypelagic (aphotic) zone into which no light penetrates. This is also called the midnight zone and the deep ocean. Due to the complete lack of sunlight, photosynthesis cannot occur and the only light source is bioluminescence.
Explanation:
The small surface zone that has light is the photic zone. The entire rest of the ocean does not have light and is the aphotic zone.
Permanent darkness below 1000 meters with bioluminescent bacteria, bottom feeders, and angler fish is where no light reaches.
What is Darkness?This is referred to the state of being dark as a result of absence of light in the area.
The light ray penetration decreases with increase in depth thereby making areas below 1000 meters dark with bioluminescent bacteria, bottom feeders, and angler fish which is why option C was chosen.
Read more about Darkness here https://brainly.com/question/24581271
how to solve x² in differential
Answer:
x² = mutiphy by them self
Explanation:
Combustion of a 1.031-g sample of a compound containing only carbon, hydrogen,
and oxygen produced 2.265 g of CO2(g) and 1.236 g of H2O(g). What is the
empirical formula of the compound?
3 국
Molar masses in g/mol: CO2 = 44.01; H20 = 18.02; C = 12.01; H = 1.01
C3H50
Answer:
C₃H₈O
Explanation:
From the question given above, the following data were obtained:
Mass of compound = 1.031 g
Mass of CO₂ = 2.265 g
Mass of H₂O = 1.236 g
Empirical formula =?
Next, we shall determine the mass of carbon, hydrogen and oxygen in the compound. This can be obtained as follow:
For carbon, C:
Mass of CO₂ = 2.265 g
Molar mass of CO₂ = 44.01 g/mol
Molar mass of C = 12.01 g/mol
Mass of C =?
Mass of C = molar mass of C / molar mass of CO₂ × mass of CO₂
Mass of C = 12.01/44.01 × 2.265
Mass of C = 0.618 g
For hydrogen, H:
Mass of H₂O = 1.236 g
Molar mass of H₂O = 18.02 g/mol
Molar mass of H₂ = 2 × 1.01 = 2.02 g/mol
Mass of H =?
Mass of H = Molar mass of H₂ / Molar mass of H₂O × Mass of H₂O
Mass of H = 2.02/18.02 × 1.236
Mass of H = 0.139 g
For oxygen, O:
Mass of compound = 1.031 g
Mass of C = 0.618 g
Mass of H = 0.139 g
Mass of O =?
Mass of O = Mass of compound – (mass of C + mass of H)
Mass of O = 1.031 – ( 0.618 + 0.139)
Mass of O = 1.031 – 0.757
Mass of O = 0.274 g
Finally, we shall determine the empirical formula. This can be obtained as follow:
C = 0.618 g
H = 0.139 g
O = 0.274 g
Divide by their molar mass
C = 0.618 / 12.01 = 0.051
H = 0.139 / 1.01 = 0.138
O = 0.274 / 16 = 0.017
Divide by the smallest
C = 0.051 / 0.017 = 3
H = 0.138 / 0.017 = 8
O = 0.017 / 0.017 = 1
Therefore, the empirical formula of the compound is C₃H₈O
Based on the data provided, the empirical formula of the compound is C₃H₈O
What is empirical formula?The empirical formula of compound is its simplest formula showing the mole ratio of the elements in the compound.
First, the mass of carbon, hydrogen and oxygen in the compound is determined first as follows:
For carbon, C:
Mass of CO₂ = 2.265 g
Molar mass of CO₂ = 44.01 g/mol
Molar mass of C = 12.01 g/mol
Mass of C = 12.01/44.01 × 2.265
Mass of C = 0.618 g
For hydrogen, H:
Mass of H₂O = 1.236 g
Molar mass of H₂O = 18.02 g/mol
Molar mass of H₂ = 2 × 1.01 = 2.02 g/mol
Mass of H = 2.02/18.02 × 1.236
Mass of H = 0.139 g
For oxygen, O:
Mass of compound = 1.031 g
Mass of C = 0.618 g
Mass of H = 0.139 g
Mass of O = Mass of compound – (mass of C + mass of H)
Mass of O = 1.031 – ( 0.618 + 0.139)
Mass of O = 0.274 g
To determine the empirical formula of a compound, the mole ratio of the elements are determined as follows:
Mole ratio = reacting mass/molar massMole ratio of the elements:
Carbon Hydrogen Oxygen
0.618 g/12.01 0.139 / 1.01 0.274 / 16
0.051 0.138 0.017
Divide by the smallest ratio to convert to whole numbers
0.051 / 0.017 0.138 / 0.017 0.017 / 0.017
3 : 8 : 1
Therefore, the empirical formula of the compound is C₃H₈O
Learn more about empirical formula at: https://brainly.com/question/24297883
At the start of a reaction, there are 0.0249 mol N2,
3.21 x 10-2 mol H2, and 6.42 x 10-4 mol NH3 in a
3.50 L reaction vessel at 375°C. If the equilibrium constant, K, for the reaction:
N2(g) + 3H2(g)= 2NH3(g)
is 1.2 at this temperature, decide whether the system is at equilibrium or not. If it is not, predict in which direction, the net reaction will proceed.
Answer:
Explanation:
The reaction is given as:
[tex]N_{2(g)} + 3H_{2(g)} \to 2NH_{3(g)}[/tex]
The reaction quotient is:
[tex]Q_C = \dfrac{[NH_3]^2}{[N_2][H_2]^3}[/tex]
From the given information:
TO find each entity in the reaction quotient, we have:
[tex][NH_3] = \dfrac{6.42 \times 10^{-4}}{3.5}\\ \\ NH_3 = 1.834 \times 10^{-4}[/tex]
[tex][N_2] = \dfrac{0.024 }{3.5}[/tex]
[tex][N_2] = 0.006857[/tex]
[tex][H_2] =\dfrac{3.21 \times 10^{-2}}{3.5}[/tex]
[tex][H_2] = 9.17 \times 10^{-3}[/tex]
∴
[tex]Q_c= \dfrac{(1.834 \times 10^{-4})^2}{(0.0711)\times (9.17\times 10^{-3})^3} \\ \\ Q_c = 0.6135[/tex]
However; given that:
[tex]K_c = 1.2[/tex]
By relating [tex]Q_c \ \ and \ \ K_c[/tex], we will realize that [tex]Q_c \ \ < \ \ K_c[/tex]
The reaction is said that it is not at equilibrium and for it to be at equilibrium, then the reaction needs to proceed in the forward direction.
What is the pH of a 6.2 x 10-5 M NaOH solution?
Answer:
4.21Explanation:
The pH of a solution can be found by using the formula
[tex]pH = - log [ {H}^{+} ][/tex]
From the question we have
[tex]ph = - log(6.2 \times {10}^{ - 5} ) \\ = 4.207608[/tex]
We have the final answer as
4.21Hope this helps you
Thermal energy naturally flows from _________ matter to _______ matter.
Answer:
Warmer
Cooler
Explanation:
what is an example of a change in genetic traits of an organism do to human affect
Answer:
A person's skin color, hair color, dimples, freckles, and blood type are all examples of genetic variations that can occur in a human population.
Explanation:
The blending together of some genes is called:
Answer:
its called molding
Explanation:
Calculate the energy of an electron in the n = 2 level of a hydrogen atom.
Answer: The energy of an electron in the n = 2 level of a hydrogen atom is 3.40 eV.
Explanation:
Given: n = 2
The relation between energy and [tex]n^{th}[/tex] orbit of an atom is as follows.
[tex]E = - \frac{13.6}{n^{2}} eV[/tex]
Substitute the values into above formula as follows.
[tex]E = - \frac{13.6}{n^{2}} eV\\= - \frac{13.6}{(2)^{2}}\\= - 3.40 eV[/tex]
The negative sign indicates that energy is being released.
Thus, we can conclude that the energy of an electron in the n = 2 level of a hydrogen atom is 3.40 eV.
In 1773 Benjamin Franklin, investigating the calming effect of oil on the water of a pond near London, observed that a teaspoonful of oil would cover about half an acre of the surface. From this information, estimate the height or thickness of an oil molecule in the floating film of oil. Then estimate the cross sectional area of an oil molecule in the floating film You may assume that Franklin used a lamp oil, like camphene, C10H16.
Required:
Calculate the thickness (in nm) of the surface film and the surface area (in nm2) occupied by an oleic acid molecule on water.
Answer:
a. 2.44 nm
b. 15.33 nm²
Explanation:
a. Calculate the thickness (in nm) of the surface film
Since the volume of a teaspoon equals V = 4.93 cm³ and the area of the oil film is half an acre = 1/2 × 4046.86 m² = 2023.43 m²
The volume of the oil film, V' equals the volume of the oil in the teaspoon, V
V' = Ah where A = cross-sectional area of oil film = 2023.43 m² = 2023.43 × 10⁴ cm² and h = height of oil film
So, V' = V
Ah = V
h = V/A
= 4.93 cm³/2023.43 × 10⁴ cm²
= 0.00244 × 10⁻⁴ cm
= 2.44 × 10⁻⁷ cm
= 2.44 × 10⁻⁷ cm × 1m/100 cm
= 2.44 × 10⁻⁹ m
= 2.44 nm
b. The surface area (in nm2) occupied by an oleic acid molecule on water.
Since the height of the oil film equals the diameter of the oil molecule, and the molecule is assumed to be a sphere of radius, r. Its surface area is thus A = 4πr²
r = h/2 = 2.44 nm/2 = 1.22 nm
A = 4πr²
A = 4π(1.22 nm)²
A = 4.88π nm²
A = 15.33 nm²
A 0.750 M sample of phosphorus pentachloride decomposes to give phosphorus trichloride and chlorine gases.If the equilibrium concentration of PCl5 is 0.650M,what is the equilibrium constant for the reaction?
PCl5(g) --------> PCl3(g)+ Cl₂(g)
A) Keq = 0.0133
B) Keq = 0.0154
C) Keq = 0.133
D) Keq = 0.154
E) Keq = 65.0
Answer:
Explanation:
Amount of phosphorus pentachloride reacted = 0.75 M - 0.65 M = 0.10 M
PCl₅(g) --------> PCl₃(g)+ Cl₂(g)
1 mole 1 mole 1 mole
Amount of phosphorus pentachloride reacted = 0.75 M - 0.65 M = 0.10 M
PCl₃(g) and Cl₂(g) formed are .10 M and .10 M
Keq = [ PCl₃] x [ Cl₂ ] / [ PCl₅ ]
= .10 M x .10 M / .65 M
= .0154
B ) is the correct choice .
3.05 moles of H2O is equivalent to (blank amount) molecules of water.
Show your work.
Answer:
[tex]1 \: mole \: = 6.02 \times {10}^{23} \: molecules \\ 3.05 \: moles \: = (3.05 \times 6.02 \times {10}^{23} ) \: molecules \\ = 1.8361 \times {10}^{24} \: molecules[/tex]
What is the Ksp expression for the dissociation of calcium oxalate?Immersive Reader
(4 Points)
Ksp=[Ca⁺²] x [C₂O₄⁻²]
Ksp=[Ca⁺²]² x [C₂O₄⁻²]
Ksp=[Ca⁺²]⁴ x [C₂O₄⁻²]
Ksp=[Ca⁺²] x [C₂O₄⁻²]²
Answer:
Ksp = [Ca⁺²] × [C₂O₄⁻²]
Explanation:
Step 1: Write the balanced reaction for the dissociation of calcium oxalate
CaC₂O₄(s) ⇄ Ca⁺²(aq) + C₂O₄⁻²(aq)
Step 2: Write the expression for the solubility product constant (Ksp) of calcium oxalate
The solubility product constant is the equilibrium constant for the dissociation reaction, that is, it is equal to the product of the concentrations of the products raised to their stoichiometric coefficients divided by the product of the concentrations of the reactants raised to their stoichiometric coefficients. It doesn't include solids nor pure liquids because their activities are 1.
Ksp = [Ca⁺²] × [C₂O₄⁻²]
chemical properties of citric acid
Answer:
Citric Acid is a weak acid with a chemical formula C6H8O7.
...
Properties of Citric Acid – C6H8O7.
C6H8O7 Citric Acid
Molecular Weight/ Molar Mass 192.124 g/mol
Density 1.66 g/cm³
Boiling Point 310 °C
Melting Point 153 °C
Hope it helps❤️
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Best answer gets Brainliest!!
Please answer the question ASAP
Scientists clarify an element based on what criteria
A)Atomic number
B)Mass number
C)Atomic mass
D)Atomic symbol
Which molecule will have double bonds?
(4 Points)
Fluorine
Nitrogen
Hydrogen
Oxygen