Answer:
Mass = 18.29 g
Explanation:
Given data:
Mass of beryllium needed = ?
Mass of nitrogen = 18.9 g
Solution:
Chemical equation:
3Be + N₂ → Be₃N₂
Number of moles of nitrogen:
Number of moles = mass/molar mass
Molar mass of nitrogen = 28 g/mol
Number of moles = 18.9 g/ 28 g/mol
Number of moles = 0.675 mol
Now we will compare the moles of nitrogen and Be.
N₂ : Be
1 : 3
0.675 : 3/1×0.675 = 2.03 mol
Mass of Be:
Mass = number of moles × molar mass
Mass = 2.03 mol × 9.01 g/mol
Mass = 18.29 g
Select the correct number of valence electrons, in order, for groups 13-18.
13, 14, 15, 16, 17, 18
5, 6, 4, 3, 8,7
3,4,5,6,7,8
18, 13, 15, 16, 17, 14
Answer:
3,4,5,6,7,8
Explanation:
Groups 13 - 18 are the main group on the periodic table
The group number corresponds the number of valence electrons they contains.
Valence electrons are the number of electrons in the outermost shell of an atom.
So group 13 - 18 corresponds to a valency of 3,4,5,6,7,8.
Groups with a valency of 8 are the noble gases.
26. A Grignard's reagent may be made by
reacting magnesium with which of the
following compound ?
(A)
Methyl amine
(B) Diethyl ether
(C
)
Ethyl iodide
(D)
Ethyl alcohol
Thermal energy is the energy an object has due to the _____ of the particles
Answer: Vibråtory movement.
Explanation: when particles bounce against each other the friction creates thermal energy. Think about what happens when you rub your hands together and they get warmer, that the friction between your hands making thermal energy.
How do I round 74,000 to have only one significant figure?
Answer:
7x10⁴.
Explanation:
Hello!
In this case, when rounding big number to a representation with less significant figures than it, we need to make sure we remove the spare figures and round up whether the next digit is five or more.
In such a way, for 74,000, we notice that 4 is not enough to round up the 7, that is why the number would contain a 7 only; moreover, to get rid of the thousand places, we need to introduce an exponent in 4 places, which means that the result would be:
7x10⁴.
Best regards!
fluorine is more reactive than chlorine.
Answer:
yes because of fluorine has higher electronegativity
How many electrons does a single hydrogen gain or lose in the following reaction?
H2 + O2 - H20
Answer:
One electron per single hydrogen atom.
Explanation:
Hello!
In this case, given the reaction:
[tex]H_2+O_2\rightarrow H_2O[/tex]
Whereas we can identify the following half-reaction for hydrogen:
[tex]H_2^0\rightarrow H_2^+[/tex]
Whereas we see that each single hydrogen atom gains one electron in order to go from 0 to +1, which is also related to an oxidation half-reaction.
Best regards!
Calculate the mass of beryllium (Be) needed to completely react with 18.9 g nitrogen gas (N2) to produce Bez N2, which is the only product of the reaction.
A. 6.19
B. 12.29
C. 18.29
D. 36.69
Answer:
C = 18.29 g
Explanation:
Given data:
Mass of beryllium needed = ?
Mass of nitrogen = 18.9 g
Solution:
Chemical equation:
3Be + N₂ → Be₃N₂
now we will calculate the number of moles of nitrogen:
Number of moles = mass/molar mass
Number of moles = 18.9 g/ 28 g/mol
Number of moles = 0.675 mol
Now we will compare the moles of nitrogen and Be from balance chemical equation.
N₂ : Be
1 : 3
0.675 : 3/1×0.675 = 2.03 mol
Number of moles of Be needed are 2.03 mol.
Mass of Beryllium:
Mass = number of moles × molar mass
Mass = 2.03 mol × 9.01 g/mol
Mass = 18.29 g
Based on the number of valence electrons indicated by its location in the periodic table ,which elements behavior would you predict to be closest to that of potassium (k)
Answer:
Na sodium or Rb rubidium
Explanation:
Because Na is present in first group all members of group 1 have 1 electron in valence shell and show similar properties.
I need help on these questions!
Answer:
See explanation
Explanation:
Given that;
E = hc/λ
h = 6.63 * 10^-34 Js
c = 3 * 10^8 ms-1
λ = ?
E = 3.978 * 10^-19 J
λ = hc/E
λ = 6.63 * 10^-34 * 3 * 10^8 /3.978 * 10^-19
λ = 19.89 * 10^-26/3.978 * 10^-19
λ = 5 * 10^-7 m The colour is green
2. E = hc/λ
E= 6.63 * 10^-34 * 3 * 10^8 /1000 * 10^-9
E = 1.989 * 10^-19 J
But
E = hf
f = E/h
f = 1.989 * 10^-19/6.63 * 10^-34
f = 3 * 10^14 Hz The radiation is infrared
3. E = hc/λ
λ= hc/E
λ= 6.63 * 10^-34 * 3 * 10^8 /2.0 * 10^-14
λ= 995 * 10^-14 m This is gamma radiation
4. E = hc/λ
E=6.63 * 10^-34 * 3 * 10^8 /620 * 10^-9
E = 3.2 * 10^-19 J
5. E = hf
E= 6.63 * 10^-34 * 2 * 10^17
E = 1326 * 10^-19 J
E = hc/λ
λ= hc/E
λ= 6.63 * 10^-34 * 3 * 10^8 /1326 * 10^-19 = 15 * 10^-9
This is ultraviolet radiation
Pressure is often defined as
Answer:
Pressure is often defined as a measure of force applied on an area, or over a unit area.
Explanation:
All the iron in a 2.000 g tablet was dissolved in an acidic solution and converted to Fe2+. This was then titrated with KMnO4. The titration required 27.50 cm3 of 0.100 mol dm-3 KMnO4. Calculate the total mass of iron in the tablet and its percentage by mass.
Answer:
0.768g of Fe are in the tablet = 38.4% by mass of Fe in the tablet
Explanation:
The balanced redox equation of Fe²⁺ with KMnO₄ in acidic medium is:
5Fe²⁺ + MnO₄⁻ + 8H⁺ → 5Fe³⁺ + Mn²⁺ + 4H₂O
Where 5 moles of Fe²⁺ react per mole of KMnO₄
The moles required of KMnO₄ are:
27.50cm³ * (1dm³ / 1000cm³) = 0.0275dm³ * (0.100mol / dm³) = 0.00275mol KMnO₄
Moles of Fe²⁺ are:
0.00275mol KMnO₄ * (5 moles Fe²⁺ / 1mol KMnO₄) = 0.01375moles of Fe²⁺
In grams (Molar mass Fe: 55.845g/mol):
0.01375moles of Fe²⁺ * (55.845g/mol) =
0.768g of Fe are in the tabletAnd percentage is:
0.768g Fe / 2.000g * 100 =
38.4% by mass of Fe in the tabletplease help me please help me
Compound is a dull white smooth solid which does not conduct electricity.
a. True
b. False
Answer:
a. True.
Explanation:
Hello!
In this case, since dullness and smoothness are characteristic of materials that are not able to conduct the electricity, as they do not provide an appropriate pathway for the electrons to move around because of their amorphous structure, we realize the answer is a. True.
On the contrary, a lustrous and robust solid, is actually able to conduct electricity because it provides the pathway for the electron movements and therefore to conduct electricity.
Best regards!
A mixture is made by combining 1.29 lb of salt and 5.35 lb of water.
What is the percentage of salt (by mass) in this mixture?
Answer:
19.47%
Explanation:
[tex]\frac{1.29}{1.29+5.35}[/tex]
Please recheck, for this answer may not be correct
Use your periodic table to determine which of the following is a non metal
A.Nitrogen
B. Lithium
C. Sodium
D. Gold
Classify each of the observed changes according to whether or not they are likely to represent evidence that a chemical reaction is occurring when performing an experiment.
May be evidence of a chemical reaction Not evidence of a chemical reaction
a solution color becoming less intense
due to dilution
bubbles (sas formation) changes in color
precipitation
explosion or fire
Answer Bank
a solid liquifying change in temperature solution colors mixing
Answer:
a solution color becoming less intense due to dilution- is not an evidence of a chemical reaction
bubbles (gas formation) - evidence of a chemical reaction
explosion or fire - evidence of a chemical reaction
changes in color- evidence of a chemical reaction
precipitation- evidence of a chemical reaction
changes in temperature - evidence of a chemical reaction
a solid liquifying - is not an evidence of a chemical reaction
solution colors mixing - is not an evidence of a chemical reaction
Explanation:
A chemical change is not easily reversible and yields new substances. It is often accompanied by a loss or gain of heat.
In the answer section, i have shown some evidences that lead us to conclude that a chemical reaction has taken place. The occurrence of a chemical change often goes with the formation of new substances as earlier stated and any of these signs may accompany the process.
For instance, when a metal is dropped in dilute acid solution, bubble of hydrogen gas indicates that a chemical reaction has taken place.
Why is it easier to switch to solar and wind energy as compared to other alternative energy sources? Select all that apply.
A. They are more cost-effective.
B. They require large, easily obtainable parcels of land.
C. They can be produced easily in areas with geothermal activity.
D. The land can be used for other purposes while supplying energy.
Answer:C. They can be produced easily in areas with geothermal activity.
D. The land can be used for other purposes while supplying energy.
Explanation:
Both c and d are correct
It is easier to switch to solar and wind energy as compared to other alternative energy sources because they can be produced easily in areas with geothermal activity and can be used for other purposes while supplying energy.
What is solar energy?Solar energy is any type of energy generated by the sun. Solar energy can be harnessed directly or indirectly for human use.
Generating energy that produces no greenhouse gas emissions from fossil fuels and reduces some types of air pollution.
Diversifying energy supply and reducing dependence on imported fuels. Creating economic development and jobs in manufacturing, installation, and more.
Hence, options C and D are correct.
Learn more about the solar energy here:
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Questlon 23 of 30
What is the term for a large group of people with similar characteristics such
as educational background and income level?
A. An interest group
B. A social class
C. A social culture
O D. A political party
SUBMIT
You want to determine the concentration of a phosphoric acid (H3PO4) solution using a standardized 0.0995 M NaOH solution. 10.00 mL of the H3PO4 solution needed to be titrated with 22.85 mL of the standardized 0.0995M NaOH solution to reach the equivalence point. What is the concentration of the H3PO4 solution
Answer:
Explanation:
H₃PO₄ + 3NaOH = Na₃PO₄ + 3 H₂O.
1 mole 3 mole
22.85 mL of the standardized 0.0995M NaOH solution will contain
.0995 x .02285 moles of NaOH
= 22.7357 x 10⁻⁴ moles of NaOH
3 moles of NaOH reacts with 1 mole of H₃PO₄
22.7357 x 10⁻⁴ moles of NaOH reacts with 1 x 22.7357 x 10⁻⁴ / 3 mole of H₃PO₄
= 7.5785 x 10⁻⁴ moles of H₃PO₄
7.5785 x 10⁻⁴ moles of H₃PO₄ is contained in 10 mL or 10⁻² L
molarity of H₃PO₄ solution = 7.5785 x 10⁻⁴ / 10⁻²
= 7.58 x 10⁻² M
= .0758 M .
which toxic gas is released in incomplete combustion?
Answer:
Incomplete combustion produces carbon monoxide (CO), a toxic gas.
Explanation:
Combustion is the rapid chemical reaction of oxygen in the air or direct oxygen, which is defined as oxidizer, with the different elements that make up the fuel (mainly carbon (C) and hydrogen (H)). These chemical reactions release energy producing local increases in temperature, which causes a flow of heat to the outside.
In other words, on the one hand you have the fuel, which is the substance that oxidizes and that you can find in a solid, liquid or gaseous state and which is made up mostly of carbon and hydrogen.
The oxidizer, for its part, is the substance that oxidizes the fuel, and it is generally the oxygen found in the air.
Certain amounts of oxidizer and fuel must come into contact for combustion to occur.
Incomplete combustion occurs when part of the fuel does not fully react. Incomplete combustion produces carbon monoxide (CO), a toxic gas.
which mineral is composed of calcium and fluorine?
Answer:
Fluorite
What is Fluorite? Fluorite is an important industrial mineral composed of calcium and fluorine (CaF2). It is used in a wide variety of chemical, metallurgical, and ceramic processes
Compound A reacts with Compound B to form only one product, Compound C, and it's known the usual percent yield of C in this reaction is 72.%. Suppose 3.5g of A are reacted with excess Compound B, and 6.5g of Compound C are successfully isolated at the end of the reaction.
A. What was the theoretical vield of C?
B. How much B was consumed by the reaction?
Answer:
A. Theoretical yield of C is 9.03 g
B. Mass of B consumed is 5.53 g
Explanation:
A. Determination of the theoretical yield of C.
Actual yield of C = 6.5 g
Percentage yield of C = 72.%
Theoretical yield of C =?
Percentage yield = Actual yield /Theoretical yield × 100
72% = 6.5 / Theoretical yield
72 / 100 = 6.5 / Theoretical yield
Cross multiply
72 × Theoretical yield = 100 × 6.5
72 × Theoretical yield = 650
Divide both side by 72
Theoretical yield = 650 / 72
Theoretical yield = 9.03 g
Therefore, the theoretical yield of C is 9.03 g
B. Determination of the mass of B consumed.
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
A + B —> C
Mass of A = 3.5 g
Mass of C = 9.03 g
Mass of B =?
A + B = C
3.5 + B = 9.03
Collect like terms
B = 9.03 – 3.5
B = 5.53 g
Thus, the mass of B consumed in the reaction is 5.53 g
Copper metal reacts with silver nitrate to produce silver metal and copper (II) nitrate.
the correct equation for this reaction is:
A: Cu + SiN—> Si + Cu2N
B: 2Cu + AgNO3–> Ag +
Cu(NO3)2
C: Cu + 2 AgNO3–> Ag + Cu(NO3)2
D:Cu + AgNO3–> Ag + CuNO3
Answer:
Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂
Explanation:
The reactants are:
Copper metal = Cu
Silver nitrate = AgNO₃
The products are:
Silver metal = Ag
Copper (II) nitrate = Cu(NO₃)₂
So, the reaction equation is given as;
Cu + 2AgNO₃ → 2Ag + Cu(NO₃)₂
This is a single displacement reaction
The number of calories listed on a food label always refers to the number in the entire package
Which of the statements about liquids and gases are true?
Both liquids and gases have a definite volume.
O The particles in liquids and gases can move past one another
freely
Both liquids and gases have a definite shape.
Neither liquids nor gases have a definite shape.
Which of the statements about liquids and gases are true?
Answer:The particles in liquids and gases can move past one another freely.
#CARRYONLEARNING #STUDYWELLWhich of the statements about liquids and gases are true?
Choosing:Both liquids and gases have a definite volume.
The particles in liquids and gases can move past one another freely
Both liquids and gases have a definite shape.
Neither liquids nor gases have a definite shape.
Answer:The particles in liquids and gases can move past one another freely.
#READINGHELPSWITHLEARNING #CARRYONLEARNING #STUDYWELLHow many electrons must nitrogen gain to become like it’s closest noble gas, Neon?
Answer:
3
Explanation:
the gravitational force between two objects depends on the distance between the objects and each object?
Answer:
Gravitational force between two objects depends on: a. The weight of the objects c. The mass of each object b. The distance between the objects d. Both b and c Please select the best answer from the choices provided A B C D
✓d
The data below shows the change in concentration of dinitrogen pentoxide over time, at 330 K, according to the following process.
2N2O5(g) = 4NO2(g) + O2
[N2O5] Time (s)
0.100 0.00
0.066 200.00
0.044 400.00
a) Find the rate of disappearance of N2O5 from t=0 s to t=200s
b) Find the rate of appearance of NO2 from t=0 s to t =200s
Answer: a) [tex]1.7\times 10^{-4}[/tex]
b) [tex]3.4\times 10^{-4}[/tex]
Explanation:
The reaction is :
[tex]2N_2O_5(g)\rightarrow 4NO_2(g)+O_2(g)[/tex]
Rate = Rate of disappearance of [tex]N_2O_5[/tex] = Rate of appearance of [tex]NO_2[/tex]
Rate = [tex]-\frac{d[N_2O_5]}{2dt}[/tex] = [tex]\frac{d[NO_2]}{4dt}[/tex]
Rate of disappearance of [tex]N_2O_5[/tex] = [tex]\frac{\text {change in concentration}}{time}[/tex] = [tex]\frac{0.100-0.066}{200-0}=1.7\times 10^{-4}[/tex]
a) Rate of disappearance of [tex]N_2O_5[/tex] = [tex]-\frac{d[N_2O_5]}{2dt}[/tex]
Rate of appearance of [tex]NO_2[/tex] = [tex]\frac{d[NO_2]}{4dt}[/tex]
b) Rate of appearance of [tex]NO_2[/tex] = [tex]\frac{d[NO_2]}{dt}=2\times 1.7\times 10^{-4}}=3.4\times 10^{-4}[/tex]
A) Find the rate of disappearance of [tex]N_2O_5[/tex] from t = 0 s to t = 200s
[tex]Rate = \frac{1}{2}(\frac{-\delta N_2O_5}{\delta t})\\\\Rate = -\frac{1}{2}(\frac{0.066 - 0.100}{200 - 0})\\\\Rate = 8.5*10^{-5}[/tex]
B) Find the rate of appearance of [tex]NO_2[/tex] from t = 0 s to t = 200s
According to rate law,
[tex]\frac{1}{2}(\frac{-\delta N_2O_5}{\delta t}) = \frac{1}{4}(\frac{\delta NO_2}{\delta t})\\\\8.5*10^{-5} = \frac{1}{4}(\frac{\delta NO_2}{\delta t})\\\\\frac{\delta NO_2}{\delta t} = 4 * 8.5*10^{-5}\\\\Rate = 3.4*10^{-4}[/tex]
For more information on rate of disappearance
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which soil would be the best for growing plants?
Honestly, its based on your preference but the best recommended one would be loam. I use loam too, and it is really good for growing the plants.
:)
A solution was diluted 1/40, and the final concentration was 20%. What was the original concentration?
The original concentration : 800%
Further explanationGiven
Diluted 1/40
Final concentration 20%
Required
The original concentration
Solution
Dilution is the process of adding solvent to get a more dilute solution.
The moles(n) before and after dilution are the same.
Can be formulated :
n₁ = n₂
M₁.V₁ = M₂.V₂
diluted 1/40(dilution factor)⇒ V₁/V₂=1/40⇒V₂/V₁=40
M₂ = 0.2(20%)
Input the value for M₁ :
M₁=M₂ x (V₂/V₁)
M₁ = 0.2 x 40
M₂ = 8(800%)
=