Answer:
110.43 degrees
Explanation:
Fluoroform is CHF3. The molecule is expected to be tetrahedral in shape.
Recall that any molecule with four electron domains and no lone pair on the central atom (AX4) is expected to be tetrahedral with a bond angle of 109.28 degrees.
This ideal bond angle of 109.28 degrees for tetrahedral molecules only obtains when all the atoms bonded to the central atom are the same. In the case of CHF3, the bond angles of the H-C-F bond(bond angle of 110.43 degrees) is different from that of the F-C-F bonds(bond angle of 108.50 degrees) because the bonding atoms (hydrogen and fluorine) have different electronegativities and all the bonds are not equivalent.
How many moles are there in 256 g of silicon
A 12 gram piece of Cu at 475 oC is placed in contact with a 15 gram piece of Cr at 265 oC.
Assume the two pieces of metal are the system and that there is no heat exchange between system and surrounding.
What is the final temperature of the two pieces of metal expressed in degree C?
Answer:
349.22°C
Explanation:
Let the final temperature of the two pieces of metal be x.
Now, the warmer metal which is C u reduces from 475°C to x. Thus Δt for C u is; Δt1 = 475 - x.
The cooler metal Cr increases in temperature from 265°C to x. Thus, it's change in temperature is Δt for Cr is; Δt2 = x - 265.
Now from conservation of energy, the amount of energy leaving the C u metal is equal to the amount of energy entering the Cr metal.
Thus;
q_lost = q_gain
Where;
q_lost = m1•c1•Δt1
q_gained = m2•c2•Δt2
Now, c1 & c2 are the specific heat capacity of C u and Cr respectively.
From online tables, c1 = 0.385 J/g°C and c2 = 0.46 J/g°C
We are given;
m1 = 12g and m2 = 15g
Thus;
12 × 0.385 × (475 - x) = 15 × 0.46 × (x - 265)
2194.5 - 4.62x = 6.9x - 1828.5
6.9x + 4.62x = 2194.5 + 1828.5
11.52x = 4023
x = 4023/11.52
x = 349.22°C
PLEASE HELP!! I WILL MARK THE 1st ONE BRAINLIEST!
Answer:
I hope you do well on the test good luck
Explanation:
How many joules are released when 30.0 g of H2O(g) condenses at 100°C?
Answer:
-6.78 × 10⁴ J
Explanation:
When water condenses (goes from the gaseous state to the liquid state) it releases energy in the form of heat. We can calculate this heat using the following expression.
Q = ΔH°cond × m
where,
Q is the heat released
ΔH°cond is the latent heat of condensation (ΔH°cond of water is -2260 J/g)
m is the mass
Q = ΔH°cond × m
Q = -2260 J/g × 30.0 g
Q = -6.78 × 10⁴ J
TRUE OR FALSE QUESTIONS
1) ___________________________ The physical properties of metals include
dullness, malleability, ductility, and conductivity.
2) ___________________________ Neutrons have a negative charge.
3) ___________________________Mendeleev was known as the father of the
periodic table.
1: FALSE The physical properties of metals include shininess, malleability, ductility, and conductivity.
2: FALSE Neutrons are the particles in an atom that have a neutral charge. They aren't positive like protons. They aren't negative like electrons.
3: TRUE Dmitri Ivanovich Mendeleev was a Russian chemist and inventor. He is best remembered for formulating the Periodic Law and creating a farsighted version of the periodic table of elements. He is also known as the "father of the periodic table"
Answer:
1.T, 2.F., 3.T
Explanation:
2 is false because electrons have a negative charge neutrons have no charge
Draw and name the structures of the carboxylic acids and esters you put together using molecular models.
Answer:
This question is incomplete
Explanation:
However, when the carboxylic acids and esters put together are obtained, the procedure below can be followed in drawing and naming them.
For carboxylic acid,
1) it should be noted that the functional group here is -COOH which is drawn as -C = OH
|
OH
2) The carbon of the functional group is included among the carbon to be counted when naming the structure. For example, the compound below is propanoic acid.
CH₃CH₂COOH - As you can see that there are 3 carbons linked chain there.
3) As can be seen in (2) above, the suffix "oic" is used to name carboxylic acids
4) The carbon chain here is saturated (meaning there is no double or triple bond within the carbon chain)
Example of a structure of carboxylic acid is
H₃C - CH₂ - CH₂ - C = OH
|
OH
The structure above is a butanoic acid
For ester
1)The functional group here is -COO- . which can be drawn as
- C = O
|
O -
(meaning one oxygen atom is double bonded to the carbon and the other oxygen atom is bonded to another carbon chain)
2) The alkyl group attached to the oxygen atom is first of all mentioned before the carbon chain attached from the left is mentioned. For example, CH₃CH₂CH₂COOCH₂CH₃ is ethyl butanoate
3) As seen from (2) above, the suffix "oate" is used to end the name of esters
4) As also seen from (2) above, the carbon of the functional group is also included while counting the carbon chain of the parent name (butanoate).
5) The carbon chains here are also saturated.
Example of this ester is
CH₃CH₂C = O
|
O - CH₂CH₃
The name of this compound is ethyl propanoate
Why does the flask have to be closed during the hydrochloric acid and sodium carbonate reaction?
Answer:
The flask has to be closed during the hydrochloric acid and sodium carbonate reaction as the resultant gas got trapped inside the closed flask.
Explanation:
The hydrochloric acid and sodium carbonate reaction was exothermic that caused the pressure to decrease. The flask has to be closed during the hydrochloric acid and sodium carbonate reaction as the resultant gas got trapped inside the closed flask.
In exothermic reactions, energy is produced in the form of heat or light.
How does the VSEPR theory explain molecular shape?
A. Valence electrons modify core electron orbitals.
B. Intermolecular forces distort electron bonds.
C. Electron pair attractions pull atoms together.
D. Electron pairs repelling each other push atoms apart.
Answer:
D. Electron pairs repelling each other push atoms apart
Explanation:
Hope this helps :) I just got it wrong on ap3x so I'm sure this is right
The VSEPR theory explain molecular shape by stating that the Electron pairs repelling each other push atoms apart. Hence, Option (D) is correct
What is VSEPR theory ?
Valence shell electron pair repulsion (VSEPR) theory, is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms.
It is also named the Gillespie-Nyholm theory after its two main developers, Ronald Gillespie and Ronald Nyholm.
Therefore, The VSEPR theory explain molecular shape by stating that the Electron pairs repelling each other push atoms apart. Hence, Option (D) is correct.
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please help 10 points asap
Answer:
opposite
Explanation:
Answer:
opposite
Explanation:
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An atom has 8 protons, 8 neutrons and 9 electrons. is thus a cation, anion, or neutral atom?
Answer:
It is an Anion because there are more electrons than protons making it negative
TRUE OR FALSE? Alloys are used more than pure metals because they are generally softer and less likely to react with air or water. WILL GIVE BRAINLIEST
Answer:
False
Explanation:
They’re used cause they’re generally harder than pure metals
Alloys are used much more than pure metals because they are generally stronger and less likely to react with air or water...
So I would say false
If the stack of bricks on the right has a mass of 240 kg, approximately what is the mass of the stack of bricks on the left?
A.
2400 kg
B.
720 kg
C.
320 kg
D.
480 kg
Answer:
720
Explanation: study island
Answer:
720
Explanation:
An excess of oxygen reacts with 451.4 g of lead, forming 374.7 g of lead(II) oxide. Calculate the percent yield of the reaction.
Answer: The percent yield of the reaction is 77.0 %
Explanation:
[tex]2Pb+O_2\rightarrow 2PbO[/tex]
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
[tex]\text{Number of moles of lead}=\frac{451.4g}{207.2g/mol}=2.18moles[/tex]
[tex]\text{Number of moles of lead oxide}=\frac{374.7g}{223.2g/mol}=1.68moles[/tex]
According to stoichiometry:
2 moles of [tex]Pb[/tex] produces = 2 moles of [tex]PbO_2[/tex]
2.18 moles of [tex]Pb[/tex] is produced by=[tex]\frac{2}{2}\times 2.18=2.18moles[/tex] of [tex]PbO_2[/tex]
Mass of [tex]PbO_2[/tex] =[tex]moles\times {\text {Molar mass}}=2.18\times 223.2g/mol=486.6[/tex]
percent yield =[tex]\frac{374.7g}{486.6g}\times 100=77.0\%[/tex]
PLEASE HELP ME!!!!!!!!!!!!!!!!!!!
WRITE A SHORT PASSAGE ON HOW FIBRES ARE SPUN
HELPPP WILL MARK AS BRAINLIEST
Answer: Spun yarn is made by twisting staple fibers together
To make a cohesive thread Or “single”. Twisting fibers, into yarn in the process called spinning can be dated back to the upper Paleolithic. Yarn spinning was one of the first processes to be industrialized.
Explanation:
Answer them please thanks
Answer:
(3) sorry if I'm wrong
7. (1-fertilization [sorry if wrong again]
8. (4-mitosis
Explanation:
I'm learning about this right now...Sorry if I'm wrong but I'm pretty sure they're right! Hope this helps tho! if I'm right maybe mark me brainliest?
HELP
What type of bond is formed between the carbon and either oxygen in CO2?
A) Single
B) Double
C) Triple
______ bonds form when 2 metal atoms share electrons.
The critical resolved shear stress for a metal is 35 MPa. Determine the maximum possible yield strength (in MPa) for a single crystal of this metal that is pulled in tension.
Answer:
The maximum possible yield strength for a single crystal is 70 MPa.
Explanation:
To find the maximum possible yield strength for a single crystal we need to use the following equation:
[tex]\sigma_{y} = \frac{\tau_{CRSS}}{m_{max}}[/tex]
Where:
[tex]m_{max}[/tex] is the maximum value for Schmid factor
[tex]\tau_{CRSS}[/tex] is the critical resolved shear stress = 35 MPa
[tex] \sigma_{y}[/tex] is the yield strength =?
The Schmid factor is given by:
[tex]m = cos(\phi)cos(\lambda)[/tex]
And its maximum value is obtained when λ = 45° and Φ = 45°, so:
[tex] m = cos(45)cos(45) = 0.5 [/tex]
Finally, the maximum possible yield strength is:
[tex]\sigma_{y} = \frac{\tau_{CRSS}}{m_{max}} = \frac{35 MPa}{0.5} = 70 MPa[/tex]
Therefore, the maximum possible yield strength for a single crystal is 70 MPa.
I hope it helps you!
A commonly held idea about influenza is that it is a disease that occurs primarily in cold weather. Doctors report incidences of illness, such as influenza, to the Centers for Disease Control (CDC). The graph below shows data for three flu seasons. Note that this graph shows data from October, week 40, of one year to July, week 28, of the following year.
Which evidence supports this idea?
The graph line for 2008-09 has the highest peaks for flu.
All three graph lines show different patterns throughout the year.
The graph line for 2008-09 has a peak in week 44.
All three graph lines peak over the same few weeks of winter.
Answer:
D.All three graph lines peak over the same few weeks of winter.
Explanation:
took the test
Which one of the following is NOT a proper unit for frequency? *
m·s–1
Hz
s–1
1/s
Answer:
m*s⁻¹.
Explanation:
Hello!
In this case, since the frequency measures how repetitive an event is per unit of time, for instance the laps a car drives every 5 minutes or something similar, we can infer it has units of event/time; in such a way, the unit m*s⁻¹ is not a proper unit of frequency because it is a proper unit of velocity which is the distance traveled per unit of time.
In such a way, Hz (hertz), s⁻¹ and 1/s are possible ways frequency can be represented.
Best regards!
Calculate the time required for a constant current of 0.868 A to deposit 0.387 g of Tl(III) as Tl(s) on a cathode.
Answer:
632.7 secs
Explanation:
Equation of the reaction:
Tl^3+ + 3e ------> Tl
If 1F = 96500 C
Q= It
Where;
I= current
t= time
3× 96500 C deposited 204 g of Tl
0.868 × t deposited 0.387 g of Tl
3 × 96500 × 0.387 = 204 × 0.868 × t
t= 3 × 96500 × 0.387/ 204 × 0.868
t= 632.7 secs
The time required for a constant current of 0.868 A to deposit 0.387 g of Tl(III) as Tl(s) is 2689 s
We'll begin by calculating the quantity of electricity needed to deposit 0.387 g of Ti
Ti³⁺ + 3e —> Ti
Recall:
1 mole of Ti = 48 g
1 electron (e) = 96500 C
Thus,
3 electrons = 3 × 96500 = 289500 C
From the balanced equation above,
48 g of Ti was deposited by 289500 C of electricity.
Therefore,
0.387 g of Ti will be deposited by = (0.387 × 289500) / 48 = 2334.09375 C of electricity
Finally, we shall determine the time required.Quantity of electricity (Q) = 2334.09375 C
Current (I) = 0.868 A
Time (t) =?t = Q / I
t = 2334.09375 / 0.868
t = 2689 sTherefore, the time required for the reaction is 2689 s
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Pls pls pls pls pls pls help
Which of the following statements is true regarding both theories and laws?
A: Change over time
B: Cannot be proven
C: Require consensus
D: Supported by observations
Answer:
D. Supported by observations
Explanation:
Because theories change over time, they both need to be proven, they do not go off of consensus, but they do need to be supported by observations.
HOPE IT HELPS❣️
The net force on a vehicle that is accelerating at a rate of 1.5m/s^2 is 1,800 newtons. What is the mass of the vehicle to the nearest kilogram?
Answer:
Explanation:
Net force F = 1800 N
acceleration a = 1.5 m /s²
mass = m
mass = force / acceleration
= 1800 / 1.5
m = 1200 kg
The mass of the vehicle to the nearest kilogram is 1200 Kg
The force acting on an object is defined by the following equation
Force (F) = mass (m) × Acceleration (a)
F = ma
With the above formula, we can obtain the mass of the vehicle as follow:
Force (F) = 1800 N
Acceleration (a) = 1.5 m/s²
Mass (m) =?[tex]m = \frac{F}{a} \\ \\ m = \frac{1800}{1.5} \\ \\ m = 1200 \: Kg[/tex]
Therefore, the mass of the vehicle is 1200 Kg
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Type in the name of the following compounds. Be sure to use the periodic table if needed.
Answer: Sulfuric Acid
Explanation: correct on edg
Answer:
Sulfuric Acid
Explanation:
correct on edg
The reaction of zinc metal and hydrochloric acid produces hydrogen gas and zinc chloride. Write the balanced chemical equation. Phases are optional.
Answer:
Zn + 2HCl -----> ZnCl₂ + H₂
Explanation:
The balanced chemical equation for Zn with hydrogen is Zn + 2HCl ---> ZnCl₂+ H₂.
What is balanced chemical equation?
A balanced chemical equation is one in which number of reactant is equal to number of products. When Zinc reacts with hydrogen it will form zinc chloride and hydrogen gas.
Here, 1 molecules of hydrochloric acid are participating in the process, and 1 molecules of hydrogen are being created.
Therefore, The balanced chemical equation for Zn with hydrogen is Zn + 2HCl ---> ZnCl₂+ H₂.
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Why is it necessary to add concentrated HCl, then water, rather than a solution of HCl to the eudiometer tube
If we add water to a concentrated acid, then the solution may boil very violently, splashing concentrated acid. If add acid to water, the solution that forms is very dilute and a small amount of heat is released.
Why do we add acid to water?When a strong acid is poured into water, it flows down the flask and mixes much better, so no boiling takes place. The addition of water to acid forms an extremely concentrated solution of acid initially. A large amount of heat is released and the solution may boil very violently, splashing concentrated acid out of the beaker and all this because the reaction is exothermic in nature.
The reason this takes place is due to a large amount of energy liberated in the hydration reaction of concentrated ions. Therefore, we add acid to water dropwise for the dilution with constant stirring and not water to acid directly.
If we add water to acid, then an exothermic reaction occurs and the solution may boil very violently. To form the dilute solution of any strong acid, you should add acid to water and the small amount of heat released is not sufficient to vaporize and spatter it.
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A Barometer reads 29.1 inches of mercury.Calculate this pressure in mmHg.
What is the answer?
This follows a simple conversion technique. Basically what the question is trying to say here is to convert 29.1 inHg to mmHg. 1 inHg is equal to 25.4 mmHg so 29.1 inHg would be equal to [tex]25.4 * 29.1[/tex] which when evaluated turns out to be: [tex]739.14[/tex]. :D
The pressure will be 739.14 mm Hg.
What is pressure?The SI unit measuring pressure would be the pascal, which measures the force of each unit area of the surface.
Calculation of pressure
It is known that 1inHg = 25.4 mm Hg.
Hence, the pressure = 25.4 × 29.1 = 739.14 mm Hg
Therefore, the pressure will be 739.14 mm Hg.
To know more about pressure
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Question in picture!!!!!!
Answer:
6 atoms
Explanation:
Why do you need to use soap when you wash oil from your hands
Answer:
Germs stick to the oil on your hands, and washing with just water doesn't work because oil and water don't mix, but soap dislodges the germs and oil from your hands
Explanation:
Answer:
You need soap to wash the oil off your hands because oil and water don't mix well and makes it difficult to remove
Explanation: