Answer:
What is the total number of valence electrons in the Lewis structure of nh4+?
Total valence electrons pairs
Total electron pairs are determined by dividing the number total valence electrons by two. For, NH4+, Total pairs of electrons are 4.
Explanation:
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Anyone wanna start a conversation
Answer:
hi 7676
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67 jyrf
876
Answer:
miss you baby talk tm
Explanation:
All organisms on Earth have the information necessary for building them coded in their genes, and each gene is a part of the organism's unique DNA molecule.
INNIN
However, some organisms get all of their genetic material from just one parent organism. When this happens, this is called
reproduction
A. singular
B. infertile
C. asexual
D. sexual
Answer:
C
Explanation:
A student dissolves 1 gram of sugar in 10 grams of water. She then
determines the mass of the solution. What is the mass of the dissolved
sugar and water? PS1-5 DOK 1
more than 11 grams<>11 grams
Answer:
11 grams
Explanation:
your welcome!!!!!
Which statement is true of a heterogeneous mixture but not of a
homogeneous mixture?
A. It is made of different substances mixed together.
B. Its components are unevenly distributed.
c. Its components are evenly distributed
D. It is made of a single type of compound.
Answer:
B
Explanation:
well heterogenous mixtures are not uniformly distributed these meaning whatever components are "mixed" can be seperated easily
a example of this can be
Soil, oil in water, ice in water
while Homogeneous mixture cannot be seen seperated
Answer: B. Its components are unevenly distributed.
Explanation:
What determines how many electrons an atom will gain, lose, or share when it forms a chemical bond?
Answer:
To be stable an atom will gain, lose, or share electrons to complete the outer most energy level (electron shell). Octet Rule because levels 2 and 3 need 8 electrons to be stable.
What are most semiconductors made from? iron copper aluminum silicon
Answer:
silicon
Explanation:
Silicon is at a higher level than germanium, tin, and lead.
Most semiconductors are made up of silicon. Thus, the correct option for this question is D.
What are semiconductors?A Semiconductor may be defined as a type of solid substance that possesses an electrical conductivity between that of an insulator and a conductor. It has a specific electrical property that allows it to function as a foundation for computers and other electronic devices.
Silicon is the most widely utilized in the manufacturing of semiconductors. Apart from this, germanium, gallium, and arsenide are also used. Among all these elements, germanium was one of the earliest semiconductors material used.
Semiconductors are widely used in the production of Integrated circuits (ICs) and electronic discrete components such as diodes and transistors.
Therefore, most semiconductors are made up of silicon. Thus, the correct option for this question is D.
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Consider the reaction H2(g) + I2(g) Double headed arrow. 2HI(g). What is the reaction quotient, Q, for this system when [H2] = 0.100 M, [I2] = 0.200 M, and [HI] = 3.50 M?
87.5
175
350
613
Answer:
163
Explanation:
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Answer:
613
Explanation:
trust me
The laser in a 3D printer uses light with a frequency of 3.844 × 1014 Hz. Calculate the wavelength of this light in nm. Show all your calculations. (Hint: Remember the speed of light!)
Answer:
The wavelength of this light is 780.4 nm.
Explanation:
Given that,
The frequency of laser light, [tex]f=3.844 \times 10^{14}\ Hz[/tex]
We need to find the wavelength of this light.
We know that,
[tex]c=f\lambda[/tex]
Where
[tex]\lambda[/tex] is the wavelength of light
So,
[tex]\lambda=\dfrac{c}{f}\\\\\lambda=\dfrac{3\times 10^8}{3.844 \times 10^{14}}\\\\=7.804\times 10^{-7}\ m\\\\=780.4\ nm[/tex]
So, the wavelength of this light is 780.4 nm.
Is H2PO3 ionic, covalent or a acid?
A) moles are in a 60-gram sample of NaCl?
1.02 moles of NaCl are present in 60 grams sample of NaCl (sodium chloride).
How we calculate moles from grams?Moles of any substance is calculated as:
n = W/M, where
W = given mass of NaCl = 60 grams (given)
M = molar mass of NaCl = 58.44 g/mole
On putting these values in the above equation, we get
n = 60 / 58.44 = 1.02 moles
Hence, 1.02 moles are present.
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Concentrated hydrochloric acid is 12.0 M. What volume of this concentrated
solution would be needed to mix with water to produce 100. mL of 5.0 M. (Hint: the
number of moles in the diluted solution must be the same as the number of moles
from the concentrated solution.)
Answer:
41.67 ml HCl
Explanation:
n = M x V
Since the number of moles is the same:
M1 x V1 = M2 x V2
V1 = M2 x V2 /M1 =(0.1 L x 5.0 M) / 12.0 M = 0.041667 L = 41.67 ml
Which one has a larger atomic radius cobalt or nickel
Two or more than two atoms with different physical or chemical properties can not combine together to form an element. Therefore, cobalt has larger atomic radius than nickel.
What is element?Element generally consist of atoms or we can atoms combine to form element. Atoms of an element is always same, means all the properties of all atoms of one type of element is same.
On going down the group of periodic table size increases due to increase in number of shells, on going from left to right in a period the size decreases because of increase in effective nuclear charge. Cobalt or nickel comes in the same period, cobalt comes first to nickel. Cobalt has larger atomic radius than nickel. Ni and Co belongs to d block.
Therefore, cobalt has larger atomic radius than nickel.
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The concentration of lead ion in a water sample is 5ppb. Calculate the amount of lead ion in 2000g of this water sample?
Answer:
10 μg or 1 x 10⁻⁵ g
Explanation:
The concentration of lead ion is given in parts by billion (ppb), which means that there are 5 micrograms (μg) of lead in 1 liter of water sample:
5 ppb = 5 μg lead ion/L
If we assume that the density of the water sample is equal to 1 g/ml (density of water at 25°C), we can say that 2000 g of sample is equal to 2000 mL:
sample volume = 2000 g x 1 mL/g = 2000 mL x 1 L/1000 mL = 2 L
Thus, the amount of lead ion in 2000 g (or 2 L) of water sample is:
mass of lead ion = 5 μg lead/L x 2 L = 10 μg x 1 g/10⁶μg = 1 x 10⁻⁵ g
Metals in group 2 of the periodic table form ionic bonds in a one-to-one ratio with nonmetals in group ______.
15
15
16
16
17
17
18
18
Answer:
7
Explanation:
Bec g1 has to lose one electron and g7 has to gain one electron
N2 + 3H2 + 2NH3 .
28.0 grams of N2 and 5.04 grams of H2 are reacted, producing 17.8 grams of NH3. What is the percent yield?
1. 62.9%
2. 84.0%
3. 52.4%
4. Not enough information is given.
5. 34.0%
6. 14.7%
7. 191%
If 28.0 grams of N2 and 5.04 grams of H2 are reacted, producing 17.8 grams of NH3. the percent yield is 52.4%. Therefore, the answer is option 3,
To calculate the percent yield, we first need to calculate the theoretical yield of NH3 based on the amounts of N2 and H2 that were reacted.
The balanced chemical equation for the reaction is:
N2 + 3H2 → 2NH3
From the equation, we can see that 1 mole of N2 reacts with 3 moles of H2 to produce 2 moles of NH3. Therefore, the moles of N2 and H2 reacted can be calculated as:
moles of N2 = mass of N2 / molar mass of N2
= 28.0 g / 28.014 g/mol
= 0.999 mol
moles of H2 = mass of H2 / molar mass of H2
= 5.04 g / 2.016 g/mol
= 2.5 mol
Since N2 is the limiting reactant (its mole value is less than H2's mole value), we can calculate the amount of NH3 produced based on the mole ratio of N2 and NH3:
moles of NH3 = 2/1 x moles of N2
= 2/1 x 0.999 mol
= 1.998 mol
The theoretical yield of NH3 can be calculated from its mole value:
mass of NH3 = moles of NH3 x molar mass of NH3
= 1.998 mol x 17.031 g/mol
= 34.06 g
Now, we can calculate the percent yield by dividing the actual yield (17.8 g) by the theoretical yield (34.06 g) and multiplying by 100:
percent yield = actual yield / theoretical yield x 100%
= 17.8 g / 34.06 g x 100%
= 52.24%
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Please help me with chemistry.
Which best describes the difference between Mitosis and Meiosis?
Mitosis occurs in plants; Meiosis occurs in animals.
Mitosis and meiosis are both forms of cell division, but mitosis creates exact replicas and meiosis creates
gametes, or sex cells, for use in sexual reproduction.
Meiosis and mitosis are both forms of genetic modification where genes are replaced with desired DNA.
Meiosis is asexual reproduction; mitosis is sexual reproduction.
Answer:
Cells produced by meiosis are genetically identical, and cells produced by mitosis are genetically unique.
Explanation:
Cells produced by mitosis possess half the genetic material of cells produced by meiosis. Mitosis only occurs in the presence of oxygen, while meiosis can occur in the absence of oxygen.
CaCO3(s)⇄CaO(s)+CO2(g) When heated strongly, solid calcium carbonate decomposes to produce solid calcium oxide and carbon dioxide gas, as represented by the equation above. A 2.0mol sample of CaCO3(s) is placed in a rigid 100.L reaction vessel from which all the air has been evacuated. The vessel is heated to 898°C at which time the pressure of CO2(g) in the vessel is constant at 1.00atm , while some CaCO3(s) remains in the vessel. (a) Calculate the number of moles of CO2(g) present in the vessel at equilibrium. (b) Write the expression for Kp, the equilibrium constant for the reaction, and determine its value at 898C.
A) The number of moles of CO₂(g) present in the vessel at equilibrium is; 1.04 moles
B) The expression for Kp, the equilibrium constant for the reaction, and its value at 898°C is; Kp = (P[CO₂] * P[CaO])/(P[CaCO₃]) and Kp = 0.0104 mol/L
How to Calculate Equilibrium Constant
We are given the reaction equation as;
CaCO₃ (s) ⇄ CaO (s) + CO₂(g)
We are given;
Number of moles of CaCO₃ used = 2 mols
Volume of vessel; V = 100 L
Temperature; T = 898°C = 1171 K
Pressure of CO₂ in the vessel; P = 1 atm
A) Formula for number of moles of CO₂ in the vessel at equilibrium is;
n = PV/RT
where;
P is Pressure
V is Volume
R is gas constant = 0.08206 L·atm/mol·k
n = (1 * 100)/(0.08206 * 1171)
n = 1.04 moles of CO₂
B) Formula to find the equilibrium constant kp is;
Kp = (P[CO₂] * P[CaO])/(P[CaCO₃])
Where;
P[CO₂] is the partial pressure of CO₂
P[CaO] is the partial pressure of CaO
P[CaCO₃] is the partial pressure of CaCO₃
Since concentration of solids is taken as 1, then it means that;
Kp = P[CO₂]
Kp = 1.04/100
Kp = 0.0104 mol/L
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Which of these statements is correct?
A. Continental crust is thinner than oceanic crust.
B. Continental and oceanic crusts have the same thickness.
C. Oceanic crust is thicker than continental crust.
D. Continental crust is thicker than oceanic crust.
Answer:
C
Explanation:
Answer:
Continental is thicker than oceanic crust
Explanation:
oceanic crust is typically 40km thick and continental is between 150km and 200km thick
The graph above represents an object moving with a __________________. A) constant velocity B) constant acceleration C) constant positive acceleration D) constant negative acceleration
Answer: I think its C or B
Explanation: Hope this was helpful....
What does replacement mean?
Answer: Replacement means a person or thing that takes the place of another; a substitute.
4. Biotic factors that affect other organisms in an ecosystem include all but which of the following factors? a. Symbiosis b. Predation C. Volcanic eruptions d. Competition
I think its d but im not sure
Answer:
Below
Explanation:
The answer is C, because ecosystems include:
Competition
Predation
Consumption
Parasitism
Disease
Symbiosis
Butane C4H10 (g),(Hf = –125.7), combusts in the presence of oxygen to form CO2 (g) (Delta.Hf = –393.5 kJ/mol), and H2O(g) (Delta.Hf = –241.82) in the reaction: 2 upper C subscript 4 upper H subscript 10 (g) plus 13 upper O subscript 2 (g) right arrow 8 upper C upper O subscript 2 plus 10 upper H subscript 2 upper O (g). What is the enthalpy of combustion, per mole, of butane? Use Delta H r x n equals the sum of delta H f of all the products minus the sum of delta H f of all the reactants.
Answer: The enthalpy of combustion, per mole, of butane is -2657.4 kJ
Explanation:
The balanced chemical reaction is,
[tex]2C_4H_{10}(g)+13O_2(g)\rightarrow 8CO_2(g)+10H_2O(g)[/tex]
The expression for enthalpy change is,
[tex]\Delta H=[n\times H_f_{products}]-[n\times H_f_{reactants}][/tex]
Putting the values we get :
[tex]\Delta H=[8\times H_f_{CO_2}+10\times H_f_{H_2O}]-[2\times H_f_{C_4H_{10}+13\times H_f_{O_2}}][/tex]
[tex]\Delta H=[(8\times -393.5)+(10\times -241.82)]-[(2\times -125.7)+(13\times 0)][/tex]
[tex]\Delta H=-5314.8kJ[/tex]
2 moles of butane releases heat = 5314.8 kJ
1 mole of butane release heat = [tex]\frac{5314.8}{2}\times 1=2657.4kJ[/tex]
Thus enthalpy of combustion per mole of butane is -2657.4 kJ
how many moles of NaCl are needed to make 5.25 L of a 0.25 M solution
Answer:
m = 21.915 g of NaC to create the right balance between
The number of moles of NaCl is 1.31 moles. This can be calculated by using the molarity formula i.e. M=n/V.
Molarity:
Molarity is defined as the ratio of the number of moles of solute to the Volume of solution in liters.
It is given by:
M = n/V
What information do we have?
Volume = 5.25 L
Molarity = 0.25 M
To find:
Moles=?
On substituting the values:
M=n/V
0.25 M =n/ 5.25 L
n= 0.25M*5.25 L
n=1.31 moles
Thus, the number of moles of NaCl are 1.31 moles.
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1 mole is equal to how many liters (volume) of any gas?
Answer:
22.4
Explanation:
you should have learned this
Answer:
At standard temperature and pressure, one mole of any gas will occupy a volume of 22.4 litres
A 45.7 block of an unknown metal at 74.2 °C is placed in 72.9 g of water at 15.9 °C. If the
final temperature of the system is 22.9 °C, what is the specific heat of the metal?
Answer:
0.934J/g°C
Explanation:
Using Q = mc∆T
However, in this question;
(Q)water = -(Q)metal
(mc∆T)water = -(mc∆T)metal
According to the information provided in the question;
For water;
m = mass = 72.9g
c = specific capacity of water = 4.184 J/g°C
∆T = 22.9 - 15.9 = 7°C
For metal;
m = mass = 45.7g
c = specific capacity of water = ?
∆T = 22.9 - 72.9 = -50°C
(mc∆T)water = -(mc∆T)metal
(72.9 × 4.184 × 7) = -(45.7 × c × -50)
2135.0952 = -(-2285c)
2135.0952 = 2285c
c = 2135.0952/2285
c of metal = 0.934J/g°C
A chemist is looking for an element that reacts similarly to the element lithium (LI). Which would be the best choice?
A gold (Au)
OB. neon (Ne)
O c. fluorine (F)
OD. sodium (Na)
When comparing all the given elements, the one that reacts similarly to the element lithium (Li) is sodium, so the best choice is D.
When comparing the properties of the given options with the properties of lithium, the one that has similar chemical characteristics as Li is Na because they are in the same group of the periodic table.
Elements are located in the periodic table in groups (columns) and periods (rows). The elements located in the same group, have similar chemical properties because they have the same number of outermost electrons located in the same outermost orbital.
In the case of Na, it is located in the same group as Li (alkali metals) in the s-block of the periodic table, so it has one outermost electron located in the s-orbital (3s¹), which is the same as Li (2s¹). This group is characterized for being soft metals and because they can react explosively with water.
The other given options have different properties:
Gold is an element located on the d-block of the periodic table (group 11), which has similar chemical properties as the other elements in its group: Cu, Ag, Rg. Neon is a noble gas located in the p-block of the periodic table (group 18). All the noble gases are characterized for having little chemical reactivity. Fluorine is a halogen located in the p-block (group 17) know for having a high chemical reactivity.
Therefore, the best choice is option D: Sodium (Na).
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did anyone hear that weird noise last night or see anything in the sky ???
Answer:
i did but i didn't see anything
Explanation:
pls help. I have the question in a ss
Answer:
D.
Explanation:
The hypothesis was that speed would increase with the addition of mass from passengers. The data shows that when passengers/mass are added, speed decreases.
please help hehehheh
Answer: C is the definete awnser so yeah its just a lol of REHEHEHEHHEHEHEHEHEHEHEHEHEHEHHEHEHEHEHEHEHEHEHHEHEHEHEHHEHEHEHEHEHEHEHEHHEHEHEHEHEHEHEHEHEHEHEHHE