Boron is an exception to the octet rule and can take up to 10 electrons in its valence shell.
True
False
Answer:
False
Explanation:
Boron is an exception to the octet rule because it possesses less than eight electrons. Boron has five electrons with three of them being valence electrons and therefore has an incomplete octet. It readily forms compounds in which it has six valence electrons, rather than the usual eight.
Hope that helps.
Considering the exception to the octet rule, the statement is false because Boron is an exception to the octet rule and can take up to 6 electrons in its valence shell.
An exception to the octet rule is when there are too few valence electrons resulting in an incomplete octet. That is, the default exceptions imply that there can be covalently bonded atoms that surround themselves with fewer than eight electrons.
This exception occurs with boron. Boron has an incomplete octet because it only has six electrons around it. That is, boron has three valence electrons and can only form electron pair bonds in two locations, gaining stability only with 6 valence electrons.
In summary, the statement is false because Boron is an exception to the octet rule and can take up to 6 electrons in its valence shell.
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A. The charge of the nuclide
B. The atomic number of the nuclide
C. The number of protons in the nuclide
D. The number of isotopes of that element
Answer:
A. The charge of the nuclide
B. The atomic number of the nuclide
C. The number of protons in the nuclide
Explanation:
The general nuclide symbol is in the picture.
Where X is the element you want to represent, A the mass number (That is mass of protons + mass of neutrons), Z is atomic number (Number of protons), and C is the charge of the nuclide.
Thus, you can determine from the nuclide symbol:
A. The charge of the nuclide . YES. Is C.
B. The atomic number of the nuclide . YES. Is Z.
C. The number of protons in the nuclide . YES. From the difference of A - Z.
D. The number of isotopes of that element. NO. It is not possible to determine number of isotopes of an element from a nuclide symbol.
What is the density of a 42.0 gram cube with a length of 5.0 cm, a width of 3.0cm, and height of 7.0cm
Answer: 0.4g per 1 cm3
Explanation:
5.0 × 3.0 × 7.0 = 105 cm3 this is the volume of cube
density is mass per unit of volume
d = m / V then 42g / 105 cm3 = 0.4 g/ 1 cm3
Predict whether the following reactions are spontaneous.
1. Pd(aq)2+H2g--------->Pd(s)+2H(aq+) Pd(aq2+) +2e- ----------> Pd(s)
E° 0.987 v
2. Sn(aq4+)+H2(g)--------->Sn(aq2+)+2H+ Sn(aq4+)+2e--------->Sn(aq)2+
E°0.154V
3. Ni(aq2+)+H2(g)--------->Ni(s)+2H(aq+) Ni(aq2+) +2e---------->Ni(s)
E° -0.250 V
4. Cd(aq2+)+H2(g--------> Cds)+2H(aq)+ Cd(aq)2 + +2e -------->
Cd(s) E°-0.403 v
From your answers, decide which of the above metals could be reduced by hydrogen
Answer:
1. spontaneous
2. spontaneous
3. Not Spontaneous
4. Not Spontaneous
Palladium and Sn^4+ can be reduced by hydrogen.
Explanation:
If we look at the electrochemical systems represented above, we will notice that in the first two cells, the metal should be reduced looking at the positive electrode potential of the process. This means that hydrogen can reduce the both metals. Electrons flow from the H2(g)/H^+(aq) half cell to the metal/metal ion half cell.
Similarly, when the standard electrode potential is negative, electrons flow from the metal/metal ion electrode to the hydrogen electrode.
Based on the reaction equations, a process is spontaneous if it gives a positive E°cell hence the answers above.
The liquid 2-chloro-2,3-dimethylbutane has a density of 0.878 g/mL at 20.0°C. If a 138 gram sample of this compound is needed, what volume of the liquid at 20.0°C must be provided? volume= mL
Answer:
157.2 mL
Explanation:
The following data were obtained from the question:
Density (D) of liquid = 0.878 g/mL
Mass (m) of liquid = 138 g
Volume (V) of liquid =.?
Density of a substance is simply defined as the mass of the substance per unit volume of the substance. Mathematically, it is expressed as:
Density (D) = mass /volume
D = m/V
With the above formula, we can obtain the volume of the liquid as follow:
Density (D) of liquid = 0.878 g/mL
Mass (m) of liquid = 138 g
Volume (V) of liquid =.?
D = m/V
0.878 = 138/V
Cross multiply
0.878 × V = 138
Divide both side by 0.878
V = 138/0.878
V = 157.2 mL
Therefore, 157.2 mL of the liquid must be provided.
A buffer solution is 0.310 M in H2SO3 and 0.304 M in NaHSO3. If Ka1 forH2SO4 is 1.7e-2 , what is the pH of this buffer solution
Answer:
pH of the buffer solution is 1.76
Explanation:
To find the pH of a buffer we can use Henderson-Hasselbalch equation:
pH = pKa + log [A⁻] / [HA]
Where pKa is -log Ka= 1.77 And [A⁻] is molar concentration of conjugate base, NaHSO₃ and [HA] molar concentration of weak acid, H₂SO₃
Replacing values of the problem:
pH = 1.77 + log [0.304M] / [0.310M]
pH = 1.76
pH of the buffer solution is 1.76Consider the two beakers labeled A and B. Beaker A contains 1 mole of iron atoms, and Beaker B contains 1 mole of lead atoms. Which statement concerning these samples is known with certainty?
The provided question is incomplete, however, the complete question is attached with answer:
Answer:
The correct answer is : option A. Beakers A and B contain an equal number of atoms.
Explanation:
No matter what is the element or substance, in one mole of any elemnet r metal or anything have 6.022×1023 everythings. So, beaker A have one mole of iron Fe and beaker B have one mole of Lead Pb, then the total atoms in each beaker will be equal that is :
1 mole of Fe = 1× 6.022×1023 atoms/mol
1 mole of Pb = 1× 6.022×1023 atoms/mol
Thus, the correct answer is: option A. Beakers A and B contain an equal number of atoms.
A sample of an unknown metal has a mass of 6.557 g. The metal was carefully added to a graduated cylinder containing 10.50 mL of water. The water level in the graduated cylinder rose to 11.16 mL. What is the density of the unknown metal?
Answer:
Explanation:
Be careful. The tricky part of the problem is that there are 4 places of sig digs.
m = 6.557 grams
V = 11.16 - 10.50 = 0.66
density = mass/ volume
density = 6.557/0.66 = 9.935 g/mL
Which of the following hypotheses is testable by using the scientific method?
a) all man are mortal
b) the best color is blue
c) no life exists on other planets
d) all swans are white
e) swimming if fun
Answer:
d
Explanation:
The only hypothesis that is testable using the scientific method would be that all swans are white.
The scientific method involves a series of steps through which scientists are able to arrive at a conclusion about the natural world. The steps include observation, drawing up falsifiable hypotheses from observations, testing the hypotheses using experiments, and then arriving at conclusions based on the data gathered from the experiment.
There is no way to test the mortality of all men as this will require harming humans in order to prove their mortality. The best color is also subjective as individuals have their preference when it comes to color. There is no way to prove the hypothesis that no life exists on other planets as this will require visiting other planets, a gesture that is practically impossible. That swimming is fun can also be subjective. Not everyone finds swimming interesting.
The hypothesis that all swans are white can be tested by sampling the population of swans in different areas and recording their colors objectively.
Hence, the correct option is d.
The hypothesis 'all swans are white' is testable by using the scientific method (Option d).
The scientific method is a series of sequential steps by which it is possible to find an explanation to scientific questions.The hypotheses are plausible explanations used by scientists to answer questions on the natural world.A hypothesis must be testable which means it is positive to make observations that agree or disagree with such explanation.In conclusion, the hypothesis 'all swans are white' is testable by using the scientific method (Option d).
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What volume is equivalent to 12.0m^3
what type of equation is MgSO4 (aq) + Na2CO3 (aq) → MgCO3 (s) + Na2SO4 (aq)
what is the color of dilute hydrochloric acid when we use the universal indicator ? only given that it is corrosive
Answer:
dark red
Explanation:
because dilute hcl is acid
dark red is the correct answer.
a sample of what looks like silver has a mass of 1.7 kg and a volume of 0.164 liters is it really silver
Answer:
It is not 100% silver, but it contains a high percentage (more than the 98% for sure) of silver.
Explanation:
Hello,
In this case, since the density of silver is 10.49 g/cm³, we can substantiate if the given sample is silver by computing is density as shown below:
[tex]\rho =\frac{m}{V}=\frac{1.7kg}{0.164L}*\frac{1000g}{1kg} *\frac{1L}{1000cm^3}\\ \\\rho=10.37g/cm^3[/tex]
In such a way, since we find a slight difference in the computed density, we can say it is not 100% silver, but it contains a high percentage (more than the 98% for sure) of silver.
Regards.
I need titration curve of sebacic acid
Answer:
is a plot showing the change in ph of the solution in the conical flask as the reagent is added from the burette
Explanation:
like, the ph of the solution at equivalence point is dependent on the strenght of the acid and strenght of the base used in the titration
A rule or principle that has not changed over a period of hundreds of years, and it is usually
a concise statement, it is a
A) Theory
B) Scientific Law
C) Scientific statement
D) Conclusion
Round off the following number to four significant figures.
273.15
Answer:
273.2
Explanation:
How many grammes of alkali are present in 150 cm ^(3) of 3 mol/dm^(3) of sodium hydroxide
Answer:I’m here for points
Explanation:yeah cuz
Explain why the ability of PLP to catalyze an amino acid transformation is greatly reduced if the OH substituent of pyridoxal phosphate is replaced by OCH3. Explain why the ability of PLP to catalyze an amino acid transformation is greatly reduced if the substituent of pyridoxal phosphate is replaced by . One of the steps in all amino acid transformations is removal of a hydrogen atom from the OH substituent of pyridoxal phosphate. One of the steps in all amino acid transformations is removal of the OH substituent of pyridoxal phosphate. The hydrogen of the OH substituent forms a hydrogen bond with the nitrogen of the imine linkage. g
Answer:
Explanation:
It should be noted that, the principle behind the ability of PLP to catalyze an amino acid transformation is greatly reduced if the OH substituent of pyridoxal phosphate is replaced by OCH3 is that; the OH is able to form a H-bond with the N which puts partial (+) on the N. This makes it easier for the AA to add to the imine C
OCH3 cannot make this H-bond w N
Which of the following is a sign a chemical reaction has occurred?
Options
A) A blue liquid is mixed into a yellow liquid, and the mixture turns green.
B) A piece of metal is placed in water and produces sparks and gas.
C) A liquid is heated in a hot plate, and bubbles form.
D) A solid powder is mixed into a liquid and disappears
Answer:
A piece of metal is placed in water and produces sparks and gas.
The sign of a chemical reaction has occurred is a piece of metal is placed in water and produces sparks and gas. The correct option is B.
What is a chemical reaction?Chemical changes, often known as chemical reactions, are the transformation of one or more compounds into one or more brand-new, separate substances. In other words, a chemical change is a process based on atomic rearrangement.
Metal is malleable and luster substance. They are gold, silver, magnesium, etc. They are present in the periodic table. Furthermore, they are highly reactive and soft.
A chemical reaction is happening in the reaction of water when it produces a spark or gas when reacting with another substance.
Thus, the correct option is B. A piece of metal is placed in water and produces sparks and gas.
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The rate constant for the equation 2 C2F4 → C4F8 is 0.0410 M−1 s −1 . We start with 0.105 mol C2F4 in a 4.00-liter container, with no C4F8 initially present. What will be the concentration of C2F4 after 3.00 hours ? Answer in units of M.
Answer:
0.002079 M
Explanation:
2 C2F4 → C4F8
Using the differential rate equation, we have;
-d[A] / dt = k x [A]²
Where [A] represent concentration of reactant; C2H4.
Upon collecting like terms we have;
(1 / [A]²) d[A] = -k x dt
Integrating both sides;
∫(1 / [A]²) d[A] = ∫-k dt
This leaves us with;
-1/[A] + 1 / [Ao] = -k ∆t
Where [A] = Final Concentration, [Ao] = Initial concentration
Arranging the equation gives us;
1 / [A] = 1 / [Ao] + k ∆t
Time = 3 hours = 10800 s (upon converting to seconds)
Inserting the values, we have;
1 / [A] = 1 / (0.105 moles / 4 L) + (0.0410 M−1 s −1 ) x (10800s)
1 / [A] = = 38.10 + 442.8 = 480.9
[A] = 0.002079 M
The concentration of C2F4 units of M is 0.0021 M.
The molarity of the solution of C2F4 is obtained from;
Molarity = Number of moles/volume
Number of moles = 0.105 mol
Volume = 4.00 L
Molarity = 0.105 mol/ 4.00 L = 0.026 M
Recall that the reaction is second order hence;
1/[A] = kt + 1/[Ao]
[A] = concentration of C2F4 at time = t
[Ao] = Initial concentration of C2F4
k = rate constant
t = time taken
1/[A] = (0.0410 × 10800) + 1/ 0.026
[A] = 0.0021 M
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odor extensive or intensive
Answer:
Odour is intensive
Explanation:
intensive properties are Independent of the amount of matter
you have liquid A, which has a density of 2g/mL. Then you have liquid B with density 10g/mL. If you mix the two materials which one will float on the top
Answer:
Liquid A
Explanation:
If two liquids are mixed together, they will eventually separate based on their density. A liquid will float if it is less dense than the liquid it is placed in.
We are given two liquids, Liquid A and Liquid B.
Liquid A has a density of 2 g/mL
Liquid B has a density of 10 g/mL
2 is less than 10, therefore Liquid A is less dense than Liquid B.
We already established that the less dense liquid will float on top. Liquid A is less dense, so Liquid A will float on top.
Carry out the following calculation, paying special attention to the significant figures (where 4/3 is exact), rounding, and units. 
3.39x10^7 g/(4/3)(3.1416)(1.65x10^2 cm)^3=____g/cm^3
Answer:
Value = 1.80 g/cm³ (Approx)
Explanation:
Given:
[tex]\frac{3.39 \times 10^7g}{(\frac{4}{3} )(3.1416)(1.65 \times 10^2 cm)^3}[/tex]
Computation:
[tex]\frac{3.39 \times 10^7g}{(\frac{4}{3} )(3.1416)(1.65 \times 10^2 cm)^3} \\\\\frac{3.39 \times 10^7g}{(\frac{4}{3} )(3.1416)(4.492125 \times 10^6 cm^3)} \\\\ \frac{3.39 \times 10^7g}{(\frac{4}{3} )(3.1416)(4.492125 \times 10^6 cm^3)}\\\\ \frac{3.39 \times 10^7g}{18.8166132\times 10^6 cm^3} \\\\ 1.80159945g/cm^3[/tex]
Value = 1.80 g/cm³ (Approx)
The density has been calculated by computing the equation as [tex]\rm 1.802\;g/cm^3[/tex].
The calculation has been performed for density, as it has been performed for mass per unit volume.
The calculations can be performed as:
[tex]\rm \implies \dfrac{3.39\;\times\;10^7\;g}{\frac{4}{3}\;\times\;(3.1416)\;(1.65\;\times\;10^2)^3\;cm^3 } \\\implies \dfrac{3.39\;\times\;10^7\;g}{\frac{4}{3}\;\times\;(3.1416)\;(4.49\;\times\;10^6)\;cm^3 }\\\implies \dfrac{3.39\;\times\;10^7\;g}{\frac{4}{3}\;\times\;14.1124\;\times\;10^6\;cm^3 }\\[/tex]
The equation has been further simplified for density as:
[tex]\rm \implies \dfrac{3.39\;\times\;10^7\;g}{18.811\;\times\;10^6\;cm^3 } \\\implies 1.802\;g/cm^3[/tex]
The density has been calculated by computing the equation as [tex]\rm 1.802\;g/cm^3[/tex].
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If 0.200 moles of AgNO₃ react with 0.155 moles of H₂SO₄ according to this UNBALANCED equation below, what is the mass in grams of Ag₂SO₄ that could be formed? AgNO₃(aq) + H₂SO₄ (aq) → Ag₂SO₄ (s) + HNO₃ (aq)
Answer:
31.2 g of Ag₂SO₄
Explanation:
We'll begin by writing the balanced equation for the reaction. This is given below:
2AgNO₃(aq) + H₂SO₄ (aq) → Ag₂SO₄ (s) + 2HNO₃ (aq)
From the balanced equation above,
2 moles of AgNO₃ reacted with 1 mole of H₂SO₄ to produce 1 mole of Ag₂SO₄ and 2 moles of HNO₃.
Next, we shall determine the limiting reactant.
This can obtained as follow:
From the balanced equation above,
2 moles of AgNO₃ reacted with 1 mole of H₂SO₄.
Therefore, 0.2 moles of AgNO₃ will react with = (0.2 x 1)/2 = 0.1 mole of H₂SO₄.
From the calculations made above, only 0.1 mole out of 0.155 mole of H₂SO₄ given is needed to react completely with 0.2 mole of AgNO₃. Therefore, AgNO₃ is the limiting reactant.
Next,, we shall determine the number of mole of Ag₂SO₄ produced from the reaction.
In this case we shall use the limiting reactant because it will give the maximum yield of Ag₂SO₄ as all of it is consumed in the reaction.
The limiting reactant is AgNO₃ and the number of mole of Ag₂SO₄ produced can be obtained as follow:
From the balanced equation above,
2 moles of AgNO₃ reacted to produce 1 mole of Ag₂SO₄.
Therefore, 0.2 moles of AgNO₃ will react to produce = (0.2 x 1)/2 = 0.1 mole of Ag₂SO₄.
Therefore, 0.1 mole of Ag₂SO₄ is produced from the reaction.
Finally, we shall convert 0.1 mole of Ag₂SO₄ to grams.
This can be obtained as follow:
Molar mass of Ag₂SO₄ = (2x108) + 32 + (16x4) = 312 g/mol
Mole of Ag₂SO₄ = 0.1
Mass of Ag₂SO₄ =?
Mole = mass /Molar mass
0.1 = Mass of Ag₂SO₄ /312
Cross multiply
Mass of Ag₂SO₄ = 0.1 x 312
Mass of Ag₂SO₄ = 31.2 g
Therefore, 31.2 g of Ag₂SO₄ were obtained from the reaction.
Taking into account the definition of reaction stoichiometry and limiting reagent, the mass of Ag₂SO₄ that could be formed is 31.18 grams.
First of all, the balanced reaction is:
2 AgNO₃ + H₂SO₄ → Ag₂SO₄ + 2 HNO₃
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
AgNO₃: 2 moles H₂SO₄: 1 mole Ag₂SO₄: 1 mole HNO₃: 2 molesThe limiting reagent is one that is consumed first in its entirety, determining the amount of product in the reaction. When the limiting reagent is finished, the chemical reaction will stop.
To determine the limiting reagent, you can use a simple rule of three as follows: if by stoichiometry 1 mole of H₂SO₄ reacts with 2 moles of AgNO₃, 0.155 moles of H₂SO₄ react with how many moles of AgNO₃?
[tex]amount of moles of AgNO_{3} =\frac{0.155 moles of H_{2}SO_{4} x 2 moles of AgNO_{3} }{1 mole of H_{2}SO_{4} }[/tex]
moles of AgNO₃= 0.31 moles
But 0.31 moles of AgNO₃ are not available, 0.200 moles are available. Since you have less moles than you need to react with 0.155 moles of H₂SO₄, AgNO₃ will be the limiting reagent.
Then, it is possible to determine the amount of moles of Ag₂SO₄ produced by another rule of three, using the limiting reagent: if by stoichiometry 2 moles of AgNO₃ produce 1 mole of Ag₂SO₄, 0.200 moles of AgNO₃ how many moles of Ag₂SO₄ will be formed?
[tex]amount of moles of Ag_{2} SO_{4} =\frac{1 mole of Ag_{2} SO_{4} x 0.200 moles of AgNO_{3} }{2 moles of AgNO_{3} }[/tex]
amount of moles of Ag₂SO₄ =0.100 moles
Finally, with 311.8 g/mole being the molar mass of Ag₂SO₄, then the mass produced of the compound can be calculated as:
[tex]0.100 molesx311.8 \frac{g}{mole} = 31.18 grams[/tex]
In summary, the mass of Ag₂SO₄ that could be formed is 31.18 grams.
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Which unit is not a measurement of volume?
cm
L
ml
Cm^3
A glass of milk has a [H+]=1×10−6. What is the pH of this milk? Is this milk an acidic or a basic solution?
Answer:
DUDE YOUR ANSWER IS:
Explanation:
GIVEN BY YOU:
[H+]=(1*10^-6)
Taking negitive log on both sides we get,
-㏒[H+]=-㏒(1*10^-6)
now by power rule of exponent, and also we know that
-㏒[H+]=PH so we get
PH= -(-6)(log(10))
as we know log(10)=1 hence by putting we get
PH=6
acidic or a basic solution:
as PH<7 hence its acidic
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As a gas changes to a solid does it lose energy or gain energy?
Answer:
It loses thermal energy and the movement of particles decreases.
Explanation:
The process of a gas turning to a solid is called condensation.
Balance equation for Magnesium + Sulphuric acid = Magnesium sulphate + Hydrogen gas
Explanation:
Hey, there!!
Your question is,
Magnesium + sulphuric acid = magnesium + hydrogen gas.
I.e.
[tex]mg + h2so4 = mgso4 + h2 \: [/tex]( hydrogen gas)
Here,
reactant and product have equal atoms.
so, it is alreday balanced.
They all are equal and alredy balanced.
Hope it helps...
Answer:
Mg + H2SO4 → MgSO4 + H2
Explanation:
The chemical equation shows magnesium (Mg) and sulfuric acid (H2SO4) on one side and magnesium sulfate (MgSO4) and hydrogen gas (H2) on the other.
Mg + H2SO4 → MgSO4 + H2
Assume that 1 mL of water contains 20 drops. How long, in hours, will it take you to count the number of drops in 4.21 gal of water at a counting rate of 10 drops/sec? 1 gal = 3.785 L. (3 significant figures, do not use scientific notation)
Answer:
8.85 hours (3 sf)
Explanation:
1 gal = 3.785 L
4.21 gal = x
x = 4.21 * 3.785 = 15.935 L
The relationship between mL and L is given as;
1000 mL = 1 L
x = 15.935L
x = 15.935 * 1000 = 15935 mL
The relationship between number of drops and mL is given as;
1 mL = 20 drops
15935 mL = x
x = 318 700 drops
The rate is 10 drops per sec
Rate = Number of drops / time
10 = 318700 / time
time = 31870 seconds
The question says to convert present the answer in hours so we convert time to hours by dividing the answer by 3600
Time = 31870 / 3600 = 8.85 hours (3 sf)
The distance measured between five successive crests of a wave motion executed by a photon of an electromagnetic radiation is 2.4cm. what is the frequency of the photon
Answer:
6.25 ×10^10 Hz
Explanation:
If the distance between five successive crests is 2.4 cm, then the distance between each crest is 2.4/5 = 0.48 cm or 0.0048 m or 4.8 ×10^-3 m
Since the velocity of a wave is given by;
v= λf
Where;
λ= wavelength of the wave
f= frequency of the wave
But λ= distance between successive crests = 4.8 ×10^-3 m
v= 3×10^8 ms-1 (speed of electromagnetic waves in vacuum)
f= v/λ
f= 3×10^8 ms-1/4.8 ×10^-3 m
f= 0.625 ×10^11 Hz
f= 6.25 ×10^10 Hz