Answer:
Mass of the unknown acid is 4.0g
Explanation:
The determine the molar mass of the unknown acid, the steps below can be followed
Firstly, determine the concentration of the acid, the formula below can be used;
ConcA × Va/ConcB × Vb = Na/Nb
Where ConcA is the concentration of the unknown acid
ConcB is the concentration of the NaOH base
Va is the volume of acid and Vb is the volume of base
Since, the titration was said to have reached an equivalent point, it means the number of moles of the acid (Na) was equal to the number of moles of the base (Nb) and thus both will be assumed to be 1
Thus
ConcA × 250/0.13 × 6.6 = 1/1
ConcA = 0.13 × 6.6/250
ConcA = 0.003432M
Then, determine the actual number of moles (n) of the unknown acid used,
ConcA = no of moles of acid/volume of acid (in dm³ or L)
To convert mL to L, we divide by 1000
Hence, 250ml = 0.25L
0.003432 = n/0.25
n = 0.003432 × 0.25
n = 0.01373 moles
To determine the molar mass;
n = mass/molar mass
The mass was given in the question to be 0.055g
Thus
0.01373 = 0.055/molar mass
molar mass = 0.055/0.01373
molar mass = 4.0g
7. All physical forms of water (solid, liquid, and gas) make up the
a. atmosphere.
b. biosphere.
C. hydrosphere.
8. The living portion of the earth is contained within the
a. lithosphere.
b. biosphere.
C. hydrosphere.
9. The correct sequence of layers of the atmosphere from innermost to outermost is
a. troposphere--stratosphere--mesosphere--thermosphere.
b. mesosphere--stratosphere--thermosphere--troposphere.
c. thermosphere--stratosphere--mesosphere--troposphere.
10. Most of Earth's weather occurs in the
a. mesosphere.
b. troposphere.
C. stratosphere.
Answer:
C. Hydrosphere for 7
B. Biosphere for 8
Explanation: I am not sure about the rest of them.
Nerve Impulses ____.
A. start at the dendrite.
B. are electrical signals.
C. can travel backwards and forwards.
D. are only found in the autonomic nervous system.
Answer:
B. are electrical signals.
Heterotrophic bacteria obtain food by
if u trust urself do it
Study these images.
4 photos of clouds. 1: Sky covered with large, flat layers of blue, grey clouds. 2: A tall, fluffy cloud shaped like an anvil. 3: Round, puffy clouds in a blue sky. 4: Thin, wispy clouds high in the sky.
Which image shows a cumulonimbus cloud?
1
2
3
Answer:
3
Explanation:
I wish you the best, its three or 2
Answer:
2
Explanation:
Edge 2021
A sample is found to contain 57.2 % N a H C O 3 NaHCOX3 by mass. What is the mass of NaHCO 3 in 4.25 g of the sample
Answer:
The mass of N a H C O 3 present is 2.431 g
Explanation:
The sample contains 57.2 % N a H C O 3 by mass.
To find the mass of N a H C O 3 in the sample, we need to find what the equivalent of 57.2 %.
Mass of N a H C O 3 = Percentage Composition * Mass of sample
Mass of N a H C O 3 = 57.2 / 100 * 4.25
Mass of N a H C O 3 = 2.431 g
The mass of N a H C O 3 present is 2.431 g
The mass of the compound (NaHCO₃) contained in 4.25 g is 2.431 g.
The given parameters;
percentage composition of the compound, = 57.2%mass of the compound (NaHCO₃) = 4.25The mass of the compound (NaHCO₃) contained in 4.25 g is calculated by the finding its equivalent in the given percent composition as follows;
[tex]mass \ = \frac{57.2}{100} \times 4.25\\\\mass = 2.431 \ g[/tex]
Thus, the mass of the compound (NaHCO₃) contained in 4.25 g is 2.431 g.
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Consider the diagram below.
What does C represent?
A) enthalpy of reaction
B) activation energy
C) activated complex
D) energy of the reactants
Answer:
A) enthalpy of reaction
Explanation:
The region C signifies the enthalpy of reaction.
This diagram is the energy profile of an endothermic reaction. In such reaction, heat is absorbed from the surrounding. At the end of the reaction, the heat of product is lesser than that of the reactants.
Enthalpy changes are heat changes accompanying a physical and chemical change. An enthalpy is the difference between the sum of the heat contents of products and sum of the heat contents of reactants.it is indeed A) enthalpy of reaction
1.191 mol N2O3 is put into a 2.00 L flask at 25°C where it decomposes into NO2(g) and NO(g). What is the equilibrium constant (to 4 decimal places) if the reaction mixture contains 0.300 mol NO2 at equilibrium?
Answer:
K = 0.0505
Explanation:
Based on the equilibrium:
N2O3 ⇄ NO2 + NO
K, equilibrium constant, is defined as:
K = [NO2] [NO] / [N2O3]
Where [] are the equilibrium concentration of each species in the mixture.
The initial molarity of N2O3 is:
1.191mol / 2.00L = 0.5955M
In equilibrium, 0.5955M of N2O3 reacts producing X Molar of NO2 and X Molar of NO:
[N2O3] = 0.5955M - X
[NO2] = X
[NO] = X
As equilibrium concentration of NO2 is 0.300mol/2.00L = 0.15M; X = 0.15M:
[N2O3] = 0.5955M - 0.15M = 0.4455M
[NO2] = 0.15M
[NO] = 0.15M
And K is:
K = [0.15M] [0.15M] / [0.4455M]
K = 0.0505
Q12. What thickness (in cm) is the silicon block (density = 2.13 g/cm3) that is 2.65 cm
wide and long necessary to react with 88.3 g of Cr2O3 by the reaction:
Si (s) + Cr203 (s) → SiO2 (s) + Cr (1)
Answer:
1.63cm
Explanation:
Given parameters:
Density of silicon = 2.13g/cm³
Mass of Cr₂O₃ = 88.3g
Width of the block = 2.65cm
Length of the block = 2.65cm
Unknown:
Thickness of the block = ?
Solution:
Reaction equation:
3Si + 2Cr₂O₃ → 3SiO₂ + 4Cr
Let us find the mass of Si,
So,
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
we find the number of moles of Cr₂O₃ ;
Molar mass of Cr₂O₃ = 2(52) + 3(16) = 152g/mol
Number of moles of Cr₂O₃ = [tex]\frac{88.3}{152}[/tex] = 0.58mole
Then;
we know that;
2 moles of Cr₂O₃ reacted with 3 moles of Cr₂O₃
0.58moles of Cr₂O₃ will react with [tex]\frac{0.58 x 3}{2}[/tex] = 0.87mole
So,
Mass of Si = number of moles x molar mass
molar mass of Si = 28g/mol
Mass of Si = 0.87 x 28 = 24.4g
Since density is the mass per unit volume of a compound;
Mass of Si = density of Si x volume of Si block
Volume of Si block = length x width x thickness = 2.65 x 2.65 x thickness
Volume of Si block = 7.02 x thickness
Mass of Si = 2.13 x 7.02 x thickness
24.4 = 15 x thickness
thickness = [tex]\frac{24.4}{15}[/tex] = 1.63cm
plz help answer both will mark brainest
Which of the following reactions will proceed as drawn below? (Yes or No)
Answer:
i wish i could help but t know either so i wish you luck for an answer once again truly sorry don'
Explanation:
i am sorry but i do not know :(
During a solar eclipse, which of the following is true?
HELP
Answer:
The moon blocks the Sun's light from hitting the surface of the earth
Explanation:
15
Density of Metals at Room Temperature
Density
Name of Metal
(g/mL)
Nickel
8.90
Copper
8.96
Palladium
12.02
smi Wetes
Silver
10.5
Platinum
21.4
Gold
19.32
Refer to the Density of Metals at Room Temperature table above. How is the density of a
metal related to its location on the Periodic Table?
A
As the metal's atomic number increases, the density increases.
B
As the metal's atomic mass increases, the density increases.
С
As the metal's number of valence electrons increases, the density increases.
D
As the metal's number of electron energy levels increases, the density increases.
Answer:
platinum = 21.4 I think it's letter D to be related to it.
In carbon dioxide (CO2), there are two oxygen atoms for each carbon atom. Each oxygen atom forms a double bond with carbon, so the molecule is formed by two double bonds.
Two double bonds means that the total number of electrons being shared in the molecule is
Answer:
The Answer is eight.
Explanation:
Sorry if it's too late and it doesn't help! But I hope you have a magnificent day! :3
Answer:
8
Explanation:
I had this question on my quiz and got it right.
assuming the temperature is held constant, how could you increase the pressure inside a container by a factor of 3
The pressure can be increased by a factor of 3 by decreasing the volume by a factor of 3.
Ideal Gas Equation:Given that the temperature of the system is held constant. So it implies that it is an isothermal process.
Now we know that the ideal gas equation is given by:
PV = nRT
where, P is the pressure
V is the volume
n is the number of moles
R is the gas constant, and
T is the temperature
Assuming n is constant, R is universal as constant, so if T is also constant, then:
PV = constant
So if P becomes 3P. that is the pressure increased by a factor of 3, then V must become V/3, so that: (3P)(V/3) = PV = constant.
Learn more about ideal gas:
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How many hydrogen atoms are there in 1.15 g of methane (CH4)?
What stress causes this type of fault to form? O compression O gravity O tension O shearing
Answer: It’s D
Explanation:
Cuz I said so
Answer: d. Shearing
Explanation:
The amount of UVA radiation hitting a surface at sea level in a lightly clouded day is about 70W/m2. About half of that can be absorbed by the skin. A typical carbon- carbon bond requires 348 kJ/mol to break. A person lies on the beach for about 1 hour without sunscreen (i.e. fully exposed to UVA radiation). Estimate the number of C-C bonds broken in this person’s back (about 0.18 m2) over that period. Assume that the average wavelength of UVA is 335 nm.
Answer:
Explanation:
Area of person's back = .18 m²
energy of radiation falling on the back per second
= 70 x .18 J
= 12.6J
Energy absorbed per second = .5 x 12.6 = 6.3 J
energy absorbed per hour = 6.3 x 60 x 60 = 22680 J
energy required to break one mole bond = 348 x 10³ J
energy required to break one bond = 348 x 10³ / 6.02 x 10²³
= 57.8 x 10⁻²⁰ J .
So number of bonds broken in one hour = 22680 / 57.8 x 10⁻²⁰
= .392 x 10²³ bonds .
= 39.2 x 10²⁰ bonds .
You are trying to confirm that your bottle of hydrochloric acid is supposedly 1.0 M, as labeled. You decided to perform a titration with 1.3 M sodium hydroxide and 100 mL of your hydrochloric acid. You expect to use 77 mL of sodium hydroxide to neutralize the acid, but in the experiment it actually took 89.13 mL of NaOH to reach the endpoint. What is the actual concentration of the hydrochloric acid?
Answer:
The actual concentration of the hydrochloric acid is 1.2M
Explanation:
The formula to be used here is that of concentration (popularly used during titration);
CₐVₐ/CbVb =nₐ/nb
where Cₐ is the concentration of acid (supposed to be 1.0 M but unsure)
Vₐ is the volume of acid (100 ml)
Cb is the concentration of base (1.3 M)
Vb is the volume of base (89.13 ml)
nₐ is the volume of acid
nb is the volume of base
The equation for the reaction described in the question is
HCl + NaOH ⇒ NaCl + H₂O
we can see from the above equation the ratio of the number of moles for both the acid and the base is 1:1
Thus;
Cₐ × 100/1.3 × 89.13 =1/1
Cₐ = 1.3 × 89.13/100
Cₐ = 1.2M
The actual concentration of the hydrochloric acid is 1.2M
Use the Rydberg Equation to calculate the energy in Joules of the transition between n = 7 and n = 3 for the hydrogen atom. Find the frequency in Hz of this transition if the wavelength is 1000nm.
Answer:
The energy of each transition is approximately [tex]1.98\times 10^{-19}\; \rm J[/tex].
The frequency of photons released in such transitions is approximately [tex]3.00\times 10^{14}\; \rm Hz[/tex].
Explanation:
The Rydberg Equation gives the wavelength (in vacuum) of photons released when the electron of a hydrogen atom transitions from one main energy level to a lower one.
Let [tex]\lambda_\text{vac}[/tex] denote the wavelength of the photon released when measured in vacuum.Let [tex]R_\text{H}[/tex] denote the Rydberg constant for hydrogen. [tex]R_\text{H} \approx 1.09678 \times 10^{7}\; \rm m^{-1}[/tex].Let [tex]n_1[/tex] and [tex]n_2[/tex] denote the principal quantum number of the initial and final main energy level of that electron. (Both [tex]n_1\![/tex] and [tex]n_2\![/tex] should be positive integers; [tex]n_1 > n_2[/tex].)The Rydberg Equation gives the following relation:
[tex]\displaystyle \frac{1}{\lambda_\text{vac}} = R_\text{H} \cdot \left(\frac{1}{{n_2}^2}} -\frac{1}{{n_1}^2}\right)[/tex].
Rearrange to obtain and expression for [tex]\lambda_\text{vac}[/tex]:
[tex]\displaystyle \lambda_\text{vac} = \frac{1}{\displaystyle R_\text{H}\cdot \left(\frac{1}{{n_2}^2} - \frac{1}{{n_1}^2}\right)}[/tex].
In this question, [tex]n_1 = 7[/tex] while [tex]n_2 = 3[/tex]. Therefore:
[tex]\begin{aligned} \lambda_\text{vac} &= \frac{1}{\displaystyle R_\text{H}\cdot \left(\frac{1}{{n_2}^2} - \frac{1}{{n_1}^2}\right)} \\ &\approx \frac{1}{\displaystyle 1.09678 \times 10^{7}\; \rm m^{-1} \cdot \left(\frac{1}{3^2} - \frac{1}{7^2}\right)} \approx 1.0 \times 10^{-6}\; \rm m \end{aligned}[/tex].
Note, that [tex]1.0\times 10^{-6}\; \rm m[/tex] is equivalent to [tex]1000\; \rm nm[/tex]. That is: [tex]1.0\times 10^{-6}\; \rm m = 1000\; \rm nm[/tex].
Look up the speed of light in vacuum: [tex]c \approx 3.00\times 10^{8}\; \rm m \cdot s^{-1}[/tex]. Calculate the frequency of this photon:
[tex]\begin{aligned} f &= \frac{c}{\lambda_\text{vac}} \\ &\approx \frac{3.00\times 10^{8}\; \rm m\cdot s^{-1}}{1.0\times 10^{-6}\; \rm m} \approx 3.00 \times 10^{14}\; \rm Hz\end{aligned}[/tex].
Let [tex]h[/tex] represent Planck constant. The energy of a photon of wavelength [tex]f[/tex] would be [tex]E = h \cdot f[/tex].
Look up the Planck constant: [tex]h \approx 6.62607 \times 10^{-34}\; \rm J \cdot s[/tex]. With a frequency of [tex]3.00\times 10^{14}\; \rm Hz[/tex] ([tex]1\; \rm Hz = 1\; \rm s^{-1}[/tex],) the energy of each photon released in this transition would be:
[tex]\begin{aligned}E &= h \cdot f \\ &\approx 6.62607 \times 10^{-34}\; \rm J\cdot s^{-1} \times 3.00 \times 10^{14}\; \rm s^{-1} \\ &\approx 1.98 \times 10^{-19}\; \rm J\end{aligned}[/tex].
The energy of the transition between n = 7 and n = 3 is 1.96 × 10^-19 J while the frequency is 3 × 10^14 Hz.
Using the Rydberg Equation for energy;
ΔE = -RH(1/n^2final - 1/n^2initial)
Given that;
nfinal = 3
ninitial = 7
RH = 2.18 × 10^-18 J
ΔE = - 2.18 × 10^-18(1/3^2 - 1/7^2)
ΔE = - 2.18 × 10^-18(0.11 - 0.02)
ΔE = - 1.96 × 10^-19 J
For the second part;
Since the wavelength is 1000nm, we have;
λ = 1000nm
c = 3 × 10^8 m/s
f = ?
c = λf
f = c/λ
f = 3 × 10^8 m/s/1000 × 10^-9 m
f = 3 × 10^8 m/s/ 1 × 10^-6 m
f = 3 × 10^14 Hz
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Which of the following particles combine to form molecules?
Compounds
Protons
Electrons
Atoms
Answer: i think its protons and electrons but it also might just be atoms because protons and electrons make atoms when there are also neutrons
Explanation:
empirical formula of N4H8O4
Answer:
NH₂O
Explanation:
Given compound:
N₄H₈O₄
Unknown:
The empirical formula of the compound = ?
Solution:
The empirical formula of a compound is its simplest formula. It expresses the composition of a the compound in the simplest whole ratio of atoms of the different elements present in the compound.
For the given compound:
N₄H₈O₄
Number of moles of N = 4
H = 8
O = 4
the highest common factor is 4 and we simply divide through by this number;
N = 1
H = 2
O = 1
So, the empirical formula of compound is NH₂O
Fossils in the gobi desert helped scientists learn?
Answer:
dinosaurs laid eggs,sabretooths were carnivores, bats lived millions of years ago ,fossils of cynobacteria exist?
Explanation:
Why is a fatty acid called a fatty acid
Answer:
Fatty acids are fairly long linear hydrocarbon chains with a carboxylic acid group at one end. Fatty acids are named based on the number of carbon atoms and carbon-carbon double bonds in the chain. ... This bond could bind a molecule of hydrogen, forming a 16-carbon molecule with no carbon-carbon double bonds.
Explanation:
Fatty acids are the fundamental blocks of fat in our bodies and our meals.
Fatty acids are carboxylic acids with long aliphatic chains that can be branched or unbranched in biochemistry. Natural fatty acids have an even number of carbon atoms and are usually unbranched. Fatty acids are important components of lipids.
They exist as esters in three different forms:
PhospholipidsTriglyceridesCholesteryl estersFatty acids that are vital to our bodies but cannot be produced in sufficient quantities within our cells are obtained from dietary sources. They are referred to as essential fatty acids. Linoleic acid and alpha-linoleic acid are two examples.
Fatty acids serve as energy sources as well as membrane constituents. They are involved in signaling, cell metabolism, and energy storage in adipose tissues.
To know more about Fatty acids,
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What is the molarity of a KCl solution made by diluting 75.0 mL of a 0.200 M solution to a final volume of 100.0 mL?
Answer:
0.150 M
Explanation:
The molarity of the solution can be calculated using the formula;
C1V1 = C2V2
Where; C1 = initial concentration of solution
C2 = final concentration of solution
V1 = volume of initial solution
V2 = volume of final solution
According to this question, C1 = 0.200M, C2 = ?, V1 = 75mL, V2 = 100.0mL
Hence,
C1V1 = C2V2
0.200 × 75 = C2 × 100
15 = 100C2
C2 = 15/100
C2 = 0.150M
Therefore, the molarity of the final KCl solution is 0.150M
I NEED HELP ASAP
Types of Cells
1) I have a cell membrane?
PROKARYOTE
EUKARYOTE *******
BOTH
2)I have a nucleus *
PROKARYOTE*****
EUKARYOTE
BOTH
3)I am a bacteria *
PROKARYOTE
EUKARYOTE
BOTH
1) Both cells have a cell membrane.
2) A nucleus is present in only Eukaryote cells.
3) I'm pretty sure Prokaryote cells are bacteria.
Hope this helps!! :)
A solution of 400mg of optically active 2-butanol in 10 mL of water, placed in a 20 cm cell shows an optical rotation of 40o. What is the specific rotation of this compound?
Answer:
Specififc rotation [∝] = 0.5° mL/g.dm
Explanation:
Given that:
mass = 400 mg
volume = 10 mL
For a solution,
The Concentration = mass/volume
Concentration = 400/10
Concentration = 40 g/mL
The path length l = 20 cm = 2 dm
Observed rotation [∝] = + 40°
Specififc rotation [∝] = ∝/l × c
where;
l = path length
c = concentration
Specififc rotation [∝] = (40 / 2 × 40)
Specififc rotation [∝] = 0.5° mL/g.dm
Using the specific rotation formular, the specific rotation obtained for the compound ls 5°
Given the Parameters :
Observed rotation, [tex] \alpha = 40° [/tex] Path length, l = 20 cm = 2 dmConcentration, C
Concentration = mass × volume
Mass = 400 mg = 400 /1000 = 0.4g
Volume = 10 mL
Concentration = 0.4g × 10 mL = 4g/mL
The specific rotation formular, [tex] [\alpha] [/tex] is given by :
[tex] [\alpha] = \frac{\alpha_{observed}}{C \times l} [/tex]
[tex] [\alpha] = \frac{40°}{4 \times 2} = \frac{40°}{8} = 5° [/tex]
Therefore, the specific rotation of the compound ls 5°
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What are the properties of gas
Answer:
1) easy compressed
2) fills its container
3) far more space
Explanation:
How many Iron (Fe) atoms should be on the products side for the equation below to obey the Law of Conversation of Mass? 25 points
2
4
1
3
Answer:
infinite
Explanation:
Explain what happened to the electrons in the elements when you exposed them to the flame. *please help
Explanation:
When you heat an atom, some of its electrons are "excited* to higher energy levels. When an electron drops from one level to a lower energy level, it emits a quantum of energy. ... The different mix of energy differences for each atom produces different colours. Each metal gives a characteristic flame emission spectrum.
A gaseous mixture contains 441.0 Torr H2(g), 387.3 Torr N2(g), and 74.5 Torr Ar(g). Calculate the mole fraction, ????, of each of these gases.
????H2=
????N2=
????Ar=
Answer:
XH₂ = 0.4885
XN₂ = 0.4290
XAr = 0.0825
Explanation:
Step 1: Given data
Partial pressure of H₂ (pH₂): 441.0 TorrPartial pressure of N₂ (pN₂): 387.3 TorrPartial pressure of Ar (pAr): 74.5 TorrStep 2: Calculate the total pressure (P)
The total pressure is equal to the sum of the partial pressures of all the gases.
P = pH₂ + pN₂ + pAr = 441.0 Torr + 387.3 Torr + 74.5 Torr = 902.8 Torr
Step 3: Calculate the mole fraction (X) of each gas
We will use the following expression.
Xi = pi / P
where,
Xi: mole fraction of the gas i
pi: partial pressure of the gas i
P: total pressure
XH₂ = pH₂ / P = 441.0 Torr / 902.8 Torr = 0.4885
XN₂ = pN₂ / P = 387.3 Torr / 902.8 Torr = 0.4290
XAr = pAr / P = 74.5 Torr / 902.8 Torr = 0.0825
