Answer:
concentration is the abundance of a constituent divided by the total volume of a mixture.
which material is a conductor of electric current?
Answer:Conduction materials include metals, electrolytes, superconductors, semiconductors, plasmas and some nonmetallic conductors such as graphite and Conductive polymers. Copper has a high conductivity.
Explanation:
The atomic number of an element is 31 and the mass number of one of its atoms is 65. This atom contains: a 31 neutrons b 34 protons c 65 protons d 34 neutrons e 34 electrons
Answer:
d, 34 neutrons
Explanation:
Mass number is the sum of the number of protons and the number of neutrons.
Atomic number equals to the number of protons.
Since the element has an atomic number of 31, it has 31 protons. The number of neutrons equal to mass number - no. of protons,
which in this case is 65 - 31
= 34 neutrons.
In a neutral atom, the no. of electrons equal to the no. of protons, because each proton carries a +1 charge and each electron carries a -1 charge. To cancel out the charge, their numbers must be equal. So, this atom has 31 electrons.
From the options, only d is correct. (34 neutrons)
Calculate the entropy change for the reaction: HCl(g) + NH3(g) -> NH4Cl(s) Entropy data: HCl: 187 J/K mol NH3: 193 J/K mol NH4Cl: 94.6 J/K mol
Answer:
-285.4 J/K
Explanation:
Let's consider the following balanced equation.
HCl(g) + NH₃(g) ⇒ NH₄Cl(s)
We can calculate the standard entropy change for the reaction (ΔS°r) using the following expression.
ΔS°r = 1 mol × S°(NH₄Cl(s)) - 1 mol × S°(HCl(g)) - 1 mol × S°(NH₃(g))
ΔS°r = 1 mol × 94.6 J/K.mol - 1 mol × 187 J/K.mol - 1 mol × 193 J/K.mol
ΔS°r = -285.4 J/K
Answer:
-198.3 J/K mol
Explanation:
I got it correct on founders edtell
What is the magnetic quantum number value for an element with n = 1?
Answer:
0,
Explanation:
if n was 2, then 1,0,-1
Which statement describes global winds?
They flow from the same direction.
They travel over short distances.
They generate land breezes.
They blow away from the poles to the equator.
Idk the answer
Answer:
They blow away from poles to the equator.
Explanation:
Hello,
In this case, we must take into account that global wind systems are formed by the constant increase in the temperature of the Earth’s surface. Thus, they drive the oceans’ surface currents. In such a way, we can say wind is the basic movement of air from an area of higher pressure to an area of lower pressure, for that reason they blow away from the poles to the equator.
Best regards.
The statement that describes the global winds is they travel over short distances.
What is winds?
Wind is a pattern or type of the movement of the natural air or any other composition of gases over to the relative position of the planet's surface.
Global winds are those winds which can travel in a straight path and originated due to global convention currents. Global winds always move from west to east direction and travels short distances only.
Hence, option (2) is correct.
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The accepted value of the number of Liters of gas in a mole is 22.4. List two possible reasons on why our experiment yielded a different value for the number of Liters in a mole of a gas.
Hint: Our experiment was conducted in July, in St. Paul, Minnesota.
Answer:
- Pressure in St. Paul, Minnesota
- Temperature in St. Paul, Minnesota
Explanation:
22.4 L or dm³ is the volume for a gas under Standard pressure and temperature conditions.
It is logically to say, that tempereature value at the day of the experiment was not 273.15 K, which is 32°F
We can say, that the pressure was not 1 atm. St Paul Minnesota has a minimum, but a little height, so the pressure differs by few figures from the standard pressure values.
We also have to mention, that 22.4 L is the value for the Ideal gases at standards conditions. Ideal gases does not exisist on practice, we always talk about real gases. Don't forget the Ideal Gases Law equation:
P . V = n . R . T
Pressure . Volume = number of moles . 0.082 L.atm /mol. K . 273.15K
Number of moles must be 1 at STP, to determine a volume of 22.4L
For each of the following names, write down the correct formula.
i. Silicon tetrafluoride
ii. Disulfur decafluoride
iii. Sulfur trioxide
iv. Diphosphorus pentoxide
v. Dichlorine oxide
Explanation:
I hope it helps you
good luck
Answer for the question
It is known that the kinetics of recrystallization for some alloy obey the Avrami equation andthat the value of n in the exponential is 2.5. If, at some temperature, the fraction recrystallized is0.40 after 200 min, determine the rate of recrystallization at this temperature.
Answer:
rate of recrystallization = 4.99 × 10⁻³ min⁻¹
Explanation:
For Avrami equation:
[tex]y = 1-e ^{(-kt^n)} \\ \\ e^{(-kt^n)} = 1-y\\ \\ -kt^n = In(1-y) \\ \\ k = \dfrac{-In(1-y)}{t^n}[/tex]
To calculate the value of k which is a dependent variable for the above equation ; we have:
[tex]k = \dfrac{-In(1-0.40)}{200^{2.5}}[/tex]
[tex]k = 9.030 \times 10 ^{-7}[/tex]
The time needed for 50% transformation can be determined as follows:
[tex]y = 1-e ^{(-kt^n)} \\ \\ e^{(-kt^n)} = 1-y\\ \\ -kt^n = In(1-y) \\ \\ t =[ \dfrac{-In(1-y)}{k}]^{^{1/n}}[/tex]
[tex]t_{0.5} =[ \dfrac{-In(1-0.4)}{9.030 \times 10^{-7}}]^{^{1/2.5}}[/tex]
= 200.00183 min
The rate of reaction for Avrami equation is:
[tex]rate = \dfrac{1}{t_{0.5}}[/tex]
[tex]rate = \dfrac{1}{200.00183}[/tex]
rate = 0.00499 / min
rate of recrystallization = 4.99 × 10⁻³ min⁻¹
For the following equilibrium, if the concentration of phosphate ion is X, what will be the molar solubility of copper phosphate? Cu3(PO4)2(s)↽−−⇀3Cu2+(aq)+2PO3−4(aq)
Answer: The molar solubility of copper phosphate is [tex]\frac{X}{2}[/tex]
Explanation:
Solubility product is defined as the equilibrium constant in which a solid ionic compound is dissolved to produce its ions in solution. It is represented as [tex]K_{sp}[/tex]
The equation is given as:
[tex]Cu_3(PO_4)_2(s)\rightarrow 3Cu^{2+}(aq)+2PO_4^{3-}[/tex]
By stoichiometry of the reaction:
1 mole of [tex]Cu_3(PO_4)_2[/tex] gives 3 moles of [tex]Cu^{2+}[/tex] and 2 moles of [tex]PO_4^{3-}[/tex]
When the solubility of [tex]Cu_3(PO_4)_2[/tex] is S moles/liter, then the solubility of [tex]Cu^{2+}[/tex] will be 3S moles\liter and solubility of [tex]PO_4^{3-}[/tex] will be 2S moles/liter.
Molar concentration of [tex]PO_4^{3-}[/tex] = X
Given : 2S = X
Thus S =[tex]\frac{X}{2}[/tex]
Thus the molar solubility of copper phosphate is [tex]\frac{X}{2}[/tex]
Choose the incorrect statement A. Replacing 3 of the H of LiALH4 with OR groups make it a more reactive reducing agents than NaBH4. B. Ester functional group has a higher priority than aldehyde in nomenclature. C. Ketones are more reactive than esters. D. Aldehydes are less reactive than acyl halides. E. Reactions of aldehydes with (1) NaBH4 and (2) H3O+ form primary alcohols.
Answer:
Replacing 3 of the H of LiALH4 with OR groups make it a more reactive reducing agents than NaBH4
Explanation:
LiAlH4 and NaBH4 are two well known reducing agents in organic chemistry. These two reducing agents function by transfer of hydrogen to the substrate.
If the hydrogen atoms in LiAlH4 are replaced by the -OR moiety, the new compound will be far less reducing than NaBH4 because the hydrogen atoms necessary to effect the reduction has been removed. Thus, the new compound containing -OR moiety can never be more reducing than NaBH4. This implies that the statement written in the answer is false as written.
Which molecule or ion has a trigonal planar shape?
Answer:B
Explanation: A P E X
If the average rate of the reaction A --->2B C is 1M/s, what is the average rate of formation (in M/s) of B over that same period of time
Answer:
[tex]r_B=2M/s[/tex]
Explanation:
Hello,
In this case, since the average rate of reaction is related with the consumption of A which has an stoichiometric coefficient of 1, the rate of formation of B will be:
[tex]r_B=2*1M/s\\\\r_B=2M/s[/tex]
By cause of the stoichiometric coefficient of B which doubles the average rate.
Best regards.
consider the following reaction
N2 + 3H2=2NH3
if 30 dm3 of each reactant react together then the volume of mixture at the end is
a 10 dm3
b 20 dm3
c 30 dm3
d 40 dm3
Answer:
d, 40 dm3.
Explanation:
According to Avogadro's law, the mole ratio of chemicals in a reaction is equal to the ratio of volumes of chemicals reacted (for gas).
From the equation, the mole ratio of N2 : H2 : NH3 = 1 : 3 : 2, meaning 1 mole of N2 reacts completely with 3 moles of H2 to give 2 moles of NH3, the ratio of volume required is also equal to 1 : 3 : 2.
Considering both N2 and H2 have 30dm3 of volume, but 1 mole of N2 reacts completely with 3 moles of H2, so we can see H2 is limiting while N2 is in excess. Using the ratio, we can deduce that 10dm3 equals to 1 in ratio (because 3 moles ratio = 30dm3).
With that being said, all H2 has reacted, meaning there's no volume of H2 left. 2 moles of NH3 is produced, meaning the volume of NH3 produced = 10 x 2 = 20 dm3. (using the ratio again)
1 mole of N2 has reacted, meaning from the 30dm3, only 10 dm3 has reacted. This also indicate that 20 dm3 of N2 has not been reacted.
So at the end, the mixture contains 20dm3 of NH3, and 20 dm3 of unreacted N2. Hence, the answer is d, 40 dm3.
Qualitatively estimate the relative melting points for each of the solids, and rank them in decreasing order.
Rank from highest to lowest melting point. To rank items as equivalent, overlap them.
sodium chloride
graphite
solid ammonia
Answer:
Graphite> sodium chloride> solid ammonia
Explanation:
Melting points of solids has a lot to do with the nature of intermolecular forces in the solid. A substance melts when the intermolecular forces holding the crystal lattice has been overcome such that that the crystal structure of the solid just collapses.
Graphite consists of covalently bonded layers of carbon atom which form a giant lattice. The melting point of graphite is very high because of the fact that the strong covalent bonds that hold the carbon atoms together in the layers require a lot of heat energy to break. Grapoghite melts at about 3600°C
Sodium chloride is an ionic compound that melts at about 801°C. The lattice is composed of alternate sodium and chloride ions.
Solid ammonia is held together by much weaker intermolecular interaction hence it has a melting point of about −77.73 °C.
Which correctly lists the three land uses that the Bureau of Land Management was originally created to manage? mining, recreation, wildlife refuges recreation, developing oil and gas, battlefields grazing, mining, developing oil and gas developing oil and gas, battlefields, wildlife refuges
Answer: C
Explanation:
Right on edge 2020
The Bureau of Land Management was originally created to manage land for grazing, mining, developing oil and gas.
What is land management?Land management refers to the activities which are done in order to protect and preserve the land as well the resources found on land.
The Bureau of Land Management was created to manage land in the US.
The Bureau of Land Management was originally created to manage land for grazing, mining, developing oil and gas.
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What is the name of the molecule below?
A) 2-pentene
B) pentane
C) 2-pentyne
D) 2-pentane
The name of the molecule which is given below is 2-pentene.
What are alkene?Alkenes are the organic compounds which are composed of carbon and hydrogen atoms, in which double bond is present.
In the given diagram:
Each corner and joints shows the carbon atoms and number of carbon atoms in it is 5.One double bond is present in the 2nd position.So the compound is 2 pentene.
Hence, 2 pentene is the name of the compound.
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If a gas is initially at a pressure of nine ATM and a volume at 21 L at a temperature of 253K and the pressure is raise to 15 ATM and the temperature is raised to 302K what will be the resulting volume of the gas
Answer:
15.0L
Explanation:
p/v = constan
(9*21)/253 =(15v)/ 302
v = (9*21*302)/(15*253)
v=15.0
To infer means to do what?
A. reach a conclusion about data
B. make a hypothesis about data
C. decide to collect some more data
D. state something found indirectly from data
Answer:
A
Explanation:
infer means use data to reach conclusion.
Ag+(aq)+2NH3(aq)⇌Ag(NH3)2+(aq) : A g + ( a q ) + 2 N H 3 ( a q ) ⇌ A g ( N H 3 ) 2 + ( a q ) : blank is the Lewis acid and blank is the Lewis base. is the Lewis acid and A g + ( a q ) + 2 N H 3 ( a q ) ⇌ A g ( N H 3 ) 2 + ( a q ) : blank is the Lewis acid and blank is the Lewis base. is the Lewis base.
Answer:
Silver ion - Lewis acid, Ammonia - Lewis base
Explanation:
The reaction is given as;
Ag+(aq) + 2NH3(aq) ⇌ [Ag(NH3)]2+(aq)
A lewis acid is an electron pair acceptor. While a lewis base is any substance that that can donate a pair of nonbonding electrons.
This reaction however is a complexation reaction, where ammonia is reacting with the silver ion.
Silver ion accepts electrons in this reaction, hence it is the lewis acid. The ammonia on the other hand donates the electrons used in bonding so it is the lewis base.
Which nonmetal is extremely nonreactive, refusing to bond with other elements except under very unusual conditions created in the laboratory?
Answer:
Helium
Explanation:
Though all noble gases are stable, helium only has two electrons and one shell so it basically doesn't have room for others.
A strontium hydroxide solution is prepared by dissolving 10.60 gg of Sr(OH)2Sr(OH)2 in water to make 47.00 mLmL of solution.What is the molarity of this solution? Express your answer to four significant figures and include the appropriate units.
Answer:
Approximately [tex]1.854\; \rm mol\cdot L^{-1}[/tex].
Explanation:
Note that both figures in the question come with four significant figures. Therefore, the answer should also be rounded to four significant figures. Intermediate results should have more significant figures than that.
Formula mass of strontium hydroxideLook up the relative atomic mass of [tex]\rm Sr[/tex], [tex]\rm O[/tex], and [tex]\rm H[/tex] on a modern periodic table. Keep at least four significant figures in each of these atomic mass data.
[tex]\rm Sr[/tex]: [tex]87.62[/tex].[tex]\rm O[/tex]: [tex]15.999[/tex].[tex]\rm H[/tex]: [tex]1.008[/tex].Calculate the formula mass of [tex]\rm Sr(OH)_2[/tex]:
[tex]M\left(\rm Sr(OH)_2\right) = 87.62 + 2\times (15.999 + 1.008) = 121.634\; \rm g \cdot mol^{-1}[/tex].
Number of moles of strontium hydroxide in the solution[tex]M\left(\rm Sr(OH)_2\right) =121.634\; \rm g \cdot mol^{-1}[/tex] means that each mole of [tex]\rm Sr(OH)_2[/tex] formula units have a mass of [tex]121.634\; \rm g[/tex].
The question states that there are [tex]10.60\; \rm g[/tex] of [tex]\rm Sr(OH)_2[/tex] in this solution.
How many moles of [tex]\rm Sr(OH)_2[/tex] formula units would that be?
[tex]\begin{aligned}n\left(\rm Sr(OH)_2\right) &= \frac{m\left(\rm Sr(OH)_2\right)}{M\left(\rm Sr(OH)_2\right)}\\ &= \frac{10.60\; \rm g}{121.634\; \rm g \cdot mol^{-1}} \approx 8.71467\times 10^{-2}\; \rm mol\end{aligned}[/tex].
Molarity of this strontium hydroxide solutionThere are [tex]8.71467\times 10^{-2}\; \rm mol[/tex] of [tex]\rm Sr(OH)_2[/tex] formula units in this [tex]47\; \rm mL[/tex] solution. Convert the unit of volume to liter:
[tex]V = 47\; \rm mL = 0.047\; \rm L[/tex].
The molarity of a solution measures its molar concentration. For this solution:
[tex]\begin{aligned}c\left(\rm Sr(OH)_2\right) &= \frac{n\left(\rm Sr(OH)_2\right)}{V}\\ &= \frac{8.71467\times 10^{-2}\; \rm mol}{0.047\; \rm L} \approx 1.854\; \rm mol \cdot L^{-1}\end{aligned}[/tex].
(Rounded to four significant figures.)
A student accidentally let some of the vapor escape the beaker. As a result of this error, will the mass of naphthalene you record be too high, too low, or unaffected? Why?
Answer:
too low
Explanation:
If our aim is to recover the naphthalene and measure its mass after separation, then we must not allow any vapour to escape.
Naphthalene is a sublime substance, it can be separated by sublimation. It changes directly from solid to gas. This vapour must be kept securely so that none of it escapes. If part of the naphthalene vapour happens to escape accidentally, then the measured mass of naphthalene will be too low compared to the mass of naphthalene originally present in the mixture.
Which is a nonpolar molecule?
Answer:
Explanation:
A nonpolar molecule has no separation of charge, so no positive or negative poles are formed. In other words, the electrical charges of nonpolar molecules are evenly distributed across the molecule. Nonpolar molecules tend to dissolve well in nonpolar solvents, which are frequently organic solvents. The answer is hydrogen cyanide.
Use the References to access important values if needed for this question.
For the following reaction, 3.83 grams of hydrogen gas are allowed to react with 9.60 grams of
ethylene (C2H4).
hydrogen(g) + ethylene (C2H4)(g) ethane (C2H)(g)
What is the maximum mass of ethane (C2H6) that can be formed?
grams
What is the FORMULA for the limiting reagent?
What mass of the excess reagent remains after the reaction is complete?
grams
Submit Answer
Retry Entire Group
9 more group attempts remaining
Answer:
A. 10.29 g of C2H6.
B. C2H4.
C. 3.14 g of H2.
Explanation:
Step 1:
We'll begin by writing the balanced equation for the reaction. This is given below:
C2H4 + H2 —> C2H6
Step 2:
Determination of the masses of C2H4 and H2 that reacted and the mass of C2H6 produced from the balanced equation.
This is illustrated below:
Molar mass of C2H4 = (12x2) + (4x1) =28 g/mol
Mass of C2H4 from the balanced equation = 1 x 28 = 28 g.
Molar mass of H2 = 2x1 = 2 g/mol
Mass of H2 from the balanced equation = 1 x 2 = 2 g.
Molar mass of C2H6 = (12x2) + (6x1) = 30 g/mol.
Mass of C2H6 from the balanced equation = 1 x 30 = 30 g
From the balanced equation above,
28 g of C2H4 reacted with 2 g of H2 to produce 30 g of C2H6.
Step 3:
Determination of the limiting reactant. This can be obtained as follow:
From the balanced equation above,
28 g of C2H4 reacted with 2 g of H2.
Therefore, 9.6 g of C2H4 will react with = (9.6 x 2)/28 = 0.69 g of H2.
From the calculations made above, we can see that only 0.69 g out of 3.83 g of H2 given is needed to react completely with 9.6 g of C2H4.
Therefore, C2H4 is the limiting reactant and H2 is the excess reactant.
A. Determination of the maximum mass of ethane, C2H6 produced from the react.
In this case, the limiting reactant will be used because it will produce the maximum yield of the reaction since all of it is consumed in the reaction.
The limiting reactant is C2H4 and the maximum mass of C2H6 can be obtained as follow:
From the balanced equation above,
28 g of C2H4 reacted to produce 30 g of C2H6.
Therefore, 9.6 gof C2H4 will react to produce = (9.6 x 30)/28 = 10.29 g of C2H6.
Therefore, 10.29 g of ethane, C2H6 were produced from the reaction.
B. The limiting reactant is ethylene with formula C2H4. Please refer to step 3 above for details.
C . Determination of the mass of the excess reactant that remained after the reaction.
The excess reactant is H2, please refer to step 3 above for details and the mass that remained after the reaction can be obtained as follow:
Mass of H2 given = 3.83 g
Mass of H2 that reacted = 0.69 g
Mass of H2 remaining =.?
Mass of H2 remaining = mass of H2 given – mass of H2 that reacted.
Mass of H2 remaining = 3.83 – 0.69
Mass of H2 remaining = 3.14 g
Therefore, 3.14 g of H2 remained after the reaction.
Where are the lanthanides and actinides found on the periodic table?
A. Columns 7 and 8
B. Columns 3 - 12, in the center of the table
C. Rows 6 and 7, separated from the rest of the table
D. Columns 1 and 2
Answer:
C. Rows 6 and 7, separated from the rest of the table
Explanation:
The lanthanides and actinides are groups of elements in the periodic table, that are thirty (30) in number. They are separated from the rest of the periodic table, usually appearing as separate rows at the bottom. They are often called the inner transition metals, because they all fill the f-block.
Therefore, the correct option is C
" They are found in Rows 6 and 7, separated from the rest of the table"
Name the physical properties used in seperating kerosene and petrol
simple distillation can be used when the temperature difference between the boiling points of two miscible liquid is at least 25°c. the temperature difference between the boiling points of kerosene and petrol is 25c. hence, this mixture can separated using simple distillation.
answer:simple distillation
Solution A has a pH of 10, and solution B has a pH of 1. Which statement best describes these solutions?
Answer:
Solution A is a Weak Alkali, Solution B is a strong Acid.
Explanation:
At pH 10, the colour is blue, therefore it's a weak alkali.
At pH 1, the colour is red, therefore it's a strong Acid.
Compute the equilibrium constant at 25 ∘C for the reaction between Sn2+(aq) and Cd(s), which form Sn(s) and Cd2+(aq). Express your answer using two significant figures
Answer:
6.1×10^8
Explanation:
The reaction is;
Sn^2+(aq) + Cd(s) -----> Sn(s) + Cd^2+(aq)
E°cell = E°cathode - E°anode
E°cathode= -0.14 V
E°anode= -0.40 V
E°cell = -0.14-(-0.40)
E°cell= -0.14+0.40
E°cell= 0.26 V
But
E°cell= 0.0592/n log K
E°cell= 0.0592/2 log K
0.26= 0.0296log K
log K = 0.26/0.0296
log K= 8.7838
K= Antilog (8.7838)
K= 6.1×10^8
Which is the correct way to write 602,200,000,000 ,000,000,000,000 in scientific notation
Answer:
6.022 × 10^23
hope this helps :)
How many moles of KOH are required to produce 4.79 g K3PO4 according to the following reaction? 3KOH + H3PO4 -----> K3PO4 + 3H2O
Answer:
0.677 moles
Explanation:
Take the atomic mass of K = 39.1, O =16.0, P = 31.0
no. of moles = mass / molar mass
no. of moles of K3PO4 used = 4.79 / (39.1x3 + 31 + 16x4)
= 0.02256 mol
From the equation, the mole ratio of KOH : K3PO4 = 3 :1,
meaning every 3 moles of KOH used, produces 1 mole of K3PO4.
So, using this ratio, let the no. of moles of KOH required to be y.
[tex]\frac{3}{1} =\frac{y}{0.02256} \\[/tex]
y = 0.02256 x3
y = 0.0677 mol
If you don't find exactly 0.677 moles as one of the options, go for the closest one. A very slight error may occur because of taking different significant figures of atomic masses when calculating.