Answer:
Atoms in group 2a are likely to form ions with a +2 charge because they have two valence electrons, both of which experience a very weak pull from the nucleus due to electron shielding. This causes the atoms to be easily pulled away from the nucleus, creating the +2 ions we see in nature.
Atoms in group 7a are likely to form ions with a -1 charge because they are one electron away from completing their outermost shell. The large number of protons in the middle of these atoms also causes the valence electrons to experience a stronger net force. This force also pulls strongly on the valence electrons of other atoms, causing the -1 ions we see in nature.
Which statement describes a major drawback of the Bohr model that caused scientists to replace it?
(A) It worked only for helium and larger atoms.
(B) It did not identify the distance between an electron and the nucleus.
(C) It contradicted the Heisenberg uncertainty principle.
(D) It stated that spectral lines of atoms are similar.
on edgen
Answer:
C.it contradicted the heinsberg uncertainly principle
Answer:
C.it contradicted the heinsberg uncertainly principle
Explanation:
if you a boy answer this question because............. idk
Answer:
no
Explanation:
How do generators use magnets to create electricity
Answer:The properties of magnets are used to make electricity.
Explanation: Moving a magnet around a coil of wire, or moving a coil of wire around a magnet, pushes the electrons in the wire and creates an electrical current. Electricity generators essentially convert kinetic energy (the energy of motion) into electrical energy.
Total enthalpy of formation of reactants and products, enthalpy of reaction. Cmon goons you’ll be rewarded handsomely
Answer:
am going to work it out
Explanation:
i am going to work it out and then tell you the answer ok
Answer this question correctly and you'll get a free brainliest. and a Thank you, etc.
Answer: When the metamorphic rock continues to heat up it will eventually melt creating molten rock. When it cools it will become igneous rock
Explanation:
:D
Answer:
As metamorphic rock continues to heat up, it can eventually melt and become molten/magma. When the molten rock cools it forms an igneous rock.
Explanation:
basically it need heat as hot as lava.
Calculate the amount of heat required to raise the temperature of a 32g sample of water from 8°C to 22°C.
Answer:
The amount of heat required to raise the temperature of a 32g sample of water from 8°C to 22°C is 1,874.432 J
Explanation:
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
Sensible heat is the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).
Between heat and temperature there is a direct proportional relationship. The constant of proportionality depends on the substance that constitutes the body and its mass, and is the product of the specific heat and the mass of the body. So, the equation that allows to calculate heat exchanges is:
Q = c * m * ΔT
where Q is the heat exchanged by a body of mass m, constituted by a substance of specific heat c and where ΔT is the variation in temperature.
In this case:
c= 4.184 [tex]\frac{J}{g*C}[/tex]m= 32 gΔT= Tfinal - Tinitial= 22°C - 8°C= 14°CReplacing:
Q= 32 g* 4.184 [tex]\frac{J}{g*C}[/tex] *14 °C
Solving:
Q= 1,874.432 J
The amount of heat required to raise the temperature of a 32g sample of water from 8°C to 22°C is 1,874.432 J
What is the molarity of calcium bicarbonate if 9.52 mL of 1.20 M HNO3 is required in a titration to neutralize 50.0 mL of a solution of Ca(HCO3)2?
The molarity of calcium bicarbonate if 9.52 mL of 1.20 M HNO3 is required in a titration to neutralize 50.0 mL of a solution of Ca(HCO3)2 is 0.228M.
HOW TO CALCULATE MOLARITY:
The molarity of a substance in a titration experiment can be calculated by using the following formula:C1V1 = C2V2
Where;
C1 = concentration of acid (M)V1 = initial volume of acid (mL)C2 = concentration of base (M)V2 = volume of the base (mL)According to this question;
V1 = 9.52mlV2 = 50.0mlC1 = 1.20MC2 = ?1.20 × 9.52 = C2 × 50
11.424 = 50C2
C2 = 11.424 ÷ 50
C2 = 0.228M
Therefore, the molarity of calcium bicarbonate if 9.52 mL of 1.20 M HNO3 is required in a titration to neutralize 50.0 mL of a solution of Ca(HCO3)2 is 0.228M.Learn more at: https://brainly.com/question/3003621?referrer=searchResults
A reaction of 2.00 ml of nitric acid and excess sodium hydroxide was carried out in
an lae calorimeter. It resulted in a change in volume of the ice/water mixture of
0.217 mL in an Ice calorimeter. The enthalpy of neutralization of nitric acid is -56.3
kJ/mol, density of Ice - 0.917 g/mL, density of water at the 0°C -1.00 g/ml, and
the enthalpy of fusion for ice - 333 J/g. Calculate the molarity of nitric acid.
-1.42 x 10-3M
-4.49 M
-7.09 M
-6.07 x 10-3M
-6.33 x 10-3M
Why are there multiple ways to represent molecules
Answer:
The different ways to represent compounds are chemical formulas and molecular models. There are so many ways to represent compounds so that a particular formula can be used depending upon how much information is provided and how much is needed to be share.
Explanation:
The representation of molecules depends on what property of the molecule we want to explore.
Representation of moleculesA molecule is composed of atoms of molecules. The representation of molecules depends on what property of the molecule we want to explore.
A molecule can be represented using;
Ball and stick modelSpace filling modelNewman projectionsIn each case, a particlar feature of the molecule is more vividly expressed.
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will give branliest
How many grams of liquid water are produced when 60 grams of ice melt? Explain why.
60 Grams are produced due to the fact that it may not produce more due to the certain capacity that varies on the size of the cube.
Is there anyone studying a doctor in pharmacy?
Answer:
no I am in 8 standard
I am already preparing for a doctor for my future
Which of the following statements correctly describes the function of cell parts?
A. The cell membrane determines which type of cell will develop.
B. The nucleus contains all the nutrients that the cell needs.
C. The mitochondria are the power plants of the cell.
D. The genes contain hemoglobin.
The statements correctly describes the function of cell parts is the mitochondria are the power plants of the cell. Therefore, option C is correct.
What do you mean by the mitochondria ?The cytoplasm of a cell contains tiny structures (fluid that surrounds the cell nucleus). The majority of a cell's energy is produced by mitochondria, which also have unique genetic material distinct from that present in the nucleus.
Oxidative phosphorylation, which produces ATP using the energy generated during the oxidation of the food we ingest, is the traditional function of mitochondria.
For the majority of biochemical and physiological activities, including growth, mobility, and equilibrium, ATP is used as the main energy source in turn.
Thus, option C is correct.
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Suppose you have 300.0 mL of a 0.450 M sodium hydroxide solution.
How many moles of sodium hydroxide are in the solution?
Answer:
135 moles
Explanation:
300*0.45
= 135
PLS GIVE BRAINLIEST
3/2 moles
Explanation:We are given:
Molarity of the solution = 0.450 M
Volume of the Solution = 300 mL OR 0.3 L
Solving for the number of moles:
We know that the formula for molarity:
M = nV (where n is the number of moles and V is the volume in Liters)
replacing the variables
0.450 = n * (0.3)
n = 0.450 / 0.3
n = 3/2 moles
Therefore, we have 3/2 moles of Na(OH) in the give solution
Please help me it due today at 11:00am please help me will mark the brainiest please
Plz what’s the answer to this
Answer: E
Explanation:hope this helps you out
A drug suspension decomposes by zero-order kinetics with a rate constant of 2 mg mL-1month-1. If the initial concentration is 100 mg mL-1, what is the shelf life (t10%)?
Answer: 5 months
Explanation: Rate Law for a reaction is an equation relating the reaction rate of reactants. It is expressed as:
aA + bB → cC + dD
[tex]r=k[A]^{a}[B]^{b}[/tex]
in which k is the rate constant of the reaction
Zero-order Kinetics is a chemical reaction in which the rate doesn't change with the variations in concentration of the reactants. At this state, it is possible to determine the final concentration by using:
[tex][A]=-kt+[A_{0}][/tex]
Shelf-Life is the time required for 10% of a drug or material to desintegrate: it is the time necessary for A to desintegrate 90% of its original concentration.
Then, the shelf-life for the drug is
[tex][A]=-kt+[A_{0}][/tex]
[tex]90=-2t+100[/tex]
2t = 10
t = 5
Shelf-life for a drug which decomposes by zero-order kinetics with rate constant of 3mgmL^{-1}month^{-1} is 5 months
The shelf life for a drug suspension decomposes by zero-order kinetics with a rate constant of 2 mg mL-1month-1 is 5 months.
How we calculate the shelf life?Shelf life for the zero order reaction will be calculated by using the below equation as:
[A] = -kt + [A₀], where
[A₀] = initial concentration of drug suspension = 100 mg/mL
[A] = Final concentration of drug suspension after 10% decomposition = 100-10 = 90mg/mol
k = rate constant = 2 mg/mL.month
t = shelf lime = to find?
On putting all these values on the above equation we get
90 = -2×t + 100
t = 10/2 = 5 months
Hence, 5 months is the shelf life.
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The magnitude of one Kelvin, one Celsius degree, and one degree on the absolute temperature scale is the same. true or false . please explain it .....
Answer:
false
Explanation:
I don't think centigrade ranges from 0 to 100 and kelvin 237 and 373 absolute -273°c and 0K
Answer:
false............................
The work done to compress a gas is 83.0 J. As a result, 27.0 J of heat is given off to the surroundings. Calculate the change in energy of the gas.
Answer:
ΔU° = 56.0 J
Explanation:
Step 1: Given data
Work done to compress the gas (w): 83.0 J (When work is done on the gas, w is positive).Heat given off to the surroundings (q): -27.0 J (When heat is released to the surroundings, q is negative)Step 2: Calculate the change in the internal energy of the gas (ΔU°)
The internal energy of a gas is the energy contained within it. We can calculate it using the following expression.
ΔU° = q + w
ΔU° = -27.0 J + 83.0 J
ΔU° = 56.0 J
Calculate the concentration of sulfate in a solution made from 65.0 mL of 0.55 M sodium sulfate and 85.0 mL of 1.25 M iron(III) sulfate?
we are given the molarity and the volume of solution. The only issue is that the volume is given in mL instead of L. This issue can be fixed by using the following conversion factor:
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
a
1000
m
L
=
1
L
Therefore, if we divide 50mL by 1000mL we will obtain a value of 0.05L.
Next, the equation has to be rearranged to solve for the moles of solute:
Moles of solute = Molarity
×
Liters of solution
Now, multiply 0.360 M by 0.05:
0.360 mol
1 L
×
0.05 L
=
0.018 mol
To obtain the mass of solute, we will need to the molar mass of NaCl, which is 58.44 g/mol:
Finally, multiply the number of moles by 58.44 g/mol
0.018
mol
×
58.44
g
1
mol
Boom, here it is:
1.05
g
An unknown piece of metal weighing 95.0 g is heated to 98.0°C. It is dropped into 250.0 g of water at 23.0°C. When equilibrium is reached, the temperature of the water and piece of metal is 29.0°C. Determine the specific heat of the metal. Assume the heat capacity of the container, a styrofoam cup, is negligible.
Answer:
[tex]C_{metal}=126.6\frac{J}{g\°C}[/tex]
Explanation:
Hello!
In this case, when two substances at different temperature are put in contact and an equilibrium temperature is attained, we can evidence that the heat lost by the hot substance (metal) is gained by the cold substance (water) and we can write:
[tex]Q_{metal}=-Q_{water}[/tex]
Which can be also written as:
[tex]m_{metal}C_{metal}(T_{EQ}-T_{metal})=-m_{water}C_{water}(T_{EQ}-T_{water})[/tex]
Thus, since we need the specific heat of the metal, we solve for it as shown below:
[tex]C_{metal}=\frac{m_{water}C_{water}(T_{EQ}-T_{water})}{-m_{metal}(T_{EQ}-T_{metal})} \\\\C_{metal}=\frac{250.0g*4.184\frac{J}{g\°C}(29.0\°C-98.0\°C)}{95.0g(29.0\°C-23.0\°C)} \\\\C_{metal}=126.6\frac{J}{g\°C}[/tex]
Best regards.
6. Choose the best answer.
The definition of consecutive is:
to get in the way of; to try to prevent
facts and information
telling the meaning of
a condition of being complicated; having many parts
following one after another
Answer:
to get in the way of;to try to prevent facts and information
When 50.0 mL of 0.400 M Ca(NO3)2 is added to 50.0 mL of 0.800 M NaF, CaF2 precipitates, as shown in the netionic equation below. The initial temperature of both solutions is 23.0°C. Assuming that the reaction goes tocompletion, and that the resulting solution has a mass of 100.00 g and a specific heat of 4.18 J/(g ∙°C), calculatethe final temperature of the solution.Ca2+(aq) + 2 F-(aq) → CaF2(s)∆H°=-11.5 kJ
Answer:
23.55°C
Explanation:
Based on the equation:
Ca²⁺(aq) + 2F⁻(aq) → CaF₂(s) ∆H°=-11.5 kJ
When 1 mole of Ca²⁺ and 2 of F⁻ reacts, 11.5kJ are released.
Thus, we need to find moles of reaction to find the heat released and using:
C = SₓmₓΔT
We can find the final temperature as follows:
Moles of reaction:
0.0500L * (0.400mol / L) = 0.0200moles Ca²⁺ = Moles of reaction
Heat produced is:
0.0200 moles * (11.5kJ / mol) = 0.23kJ
Using:
C = SₓmₓΔT
Where C is heat = 230J
S is specific heat = 4.18J/g
m is mass of solution = 100.00g
And ΔT is change in temperature
230J = 4.18J/gₓ100.00gₓΔT
ΔT = 0.55°C
As initial temperature is 23.0°C
Final temperature = 23.0°C + 0.55°C =
23.55°CThe final temperature of the solution is 23.55°C.
We were given the equation
Ca²⁺(aq) + 2F⁻(aq) → CaF₂(s) ∆H°=-11.5 kJ
This means that 1 mole of Ca²⁺ and 2 of F⁻ reacts to form CaF₂ and 1.5kJ is released.
The formula we need to use is C = SₓmₓΔT
where c is heat, s is specific heat, m is number of mole and ΔT is temperature change.
We need to find the moles of reaction first
Moles of reaction = 0.0500L × (0.400mol / L) = 0.0200moles Ca²⁺
Heat produced = 0.0200 moles ×11.5kJ / mol = 0.23kJ
We can then substitute into the formula
C = SₓmₓΔT
C = 230J
S = 4.18J/g
m = 100.00g
ΔT= ?
230J = 4.18J/gₓ100.00gₓΔT
= 0.55°C
Since the initial temperature is 23.0°C
The Final temperature will be 23.0°C + 0.55°C
=23.55°C
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A system absorbs 191 kJkJ of heat and the surroundings do 120 kJkJ of work on the system. Part A What is the change in internal energy of the system?
Answer: the change in internal energy of the system is 311 kJ
Explanation:
Given that;
A system absorbs a heat dQ = 191 kJ
And the the surroundings do work on the system dW = 120 kJ
change in internal energy of the system = ?
We take a look at the first law of thermodynamic
Initially the system absorbs energy ( dQ =1 91 kJ) as heat.
Then the surroundings do work (dW = 120kJ) on the system,
Hence the system gains 120 kJ more.
The total energy change is = heat + work
dU = dQ + dW
dU = 191 + 120
dU = 307 kJ
change in internal energy = 311 kJ
Therefore the change in internal energy of the system is 311 kJ
11
Which statement correctly describes both gases and liquids?"
Answer:
what are the statments?
Explanation:
How can energy from the Sun be used to heat water? What
things will affect how well the sunlight heats water?
Answer:
Water is heated as it travels through flat, glazed panels known as solar collectors, which are normally situated on the roof of the building. The heated water is then stored in an insulated storage tank.
Which of the following elements will lose electrons to form an ion
Answer:
Metals
Explanation:
Metallic elements are renowned for their ability to freely lose electrons to form ions.
This is because metals are electropositive in nature. When a substance is electropositive, it readily wants to lose electrons and form positive ions.
Non-metals prefers to gain electrons and are electronegative.
Demonstrate how you can prepare 250ml 0.25M hydrogen peroxide from a solution of 20g/100ml of hydrogen peroxide.
To prepare 250 ml 0.25 M hydrogen peroxide, 10.63 ml of 20g/100 ml hydrogen peroxide has been taken and made up the volume to 250 ml.
The dilution of the sample can be prepared with the help of expression:
M1V1 = M2V2
M1 = molarity of the concentrated solution
V1 = volume of concentrated solution
M2 = molarity of diluted solution
V2 = volume of diluted solution.
The molarity of concentrated solution has been:
Molarity = [tex]\rm \dfrac{weight}{molecular\;weight}\;\times\;\dfrac{1000}{Volume\;(ml)}[/tex]
The 20g/100 ml Hydrogen peroxide has molarity:
Molarity = [tex]\rm \dfrac{20}{34.0147}\;\times\;\dfrac{1000}{100}[/tex]
Molarity of Hydrogen peroxide = 5.879 M
The volume of 5.879 M hydrogen peroxide is required to prepare 0.25 M hydrogen peroxide has been:
Volume of Hydrogen peroxide (20g/100 ml) [tex]\times[/tex] 5.879 = 250 ml [tex]\times[/tex] 0.25 M
Volume of Hydrogen peroxide (20g/100 ml) = 10.63 ml.
To prepare 250 ml 0.25 M hydrogen peroxide, 10.63 ml of 20g/100 ml hydrogen peroxide has been taken and made up the volume to 250 ml.
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A sample of 7.4 L of NH3 gas at 22 ∘C and 735 torr is bubbled into a 0.50-L solution of 0.35 M HCl. Assuming that all the NH3 dissolves and that the volume of the solution remains 0.50 L, calculate the pH of the resulting solution.Kb for Nh3=1.8x10-5
Answer:
pH = 9.11
Explanation:
First, using gas law, we will determine the moles of NH3 bubbled. Then, with moles of HCl we can determine how many NH4⁺ are produced. As last, using H-H equation for bases we can find pOH and pH of the solution:
Moles NH3:
PV = nRT
P = pressure: 743 torr * (1atm / 760torr) = 0.9776atm
V = volume: 7.4L
n = Moles. Our incognite
R = Gas constant: 0.082atmL/molK
T is absolute temperature: 273.15K + 22°C = 295.15K
PV / RT = n
0.9776atm*7.4L / 0.082atmL*295.15K = 0.30 moles of NH3
Moles HCl:
0.50L * (0.35mol / L) = 0.175 moles of HCl
Based on the reaction:
NH3 + HCl → NH4⁺ + Cl⁻
All HCl added is producing NH₄⁺ = 0.175 moles NH₄⁺
Moles NH₃: 0.30moles NH3 - 0.175 moles = 0.125 moles NH₃
H-H equation for bases is:
pOH = pKb + log [BH+] / [B]
Where pKb = -log Kb = 4.74
[BH+] could be taken as moles of NH4+ = 0.175 mol
[B] are moles of NH3 = 0.125 mol
pOH = pKb + log [BH+] / [B]
pOH = 4.74 + log [0.175mol] / [0.125mol]
pOH = 4.89
pH = 14-pOH
pH = 9.11
Bond Energy
Using the table calculate the overall energy change for this reaction.
1. How much energy is needed for bond breaking?
2. How much energy is needed for bond making?
3. What is the overall energy change? (overall energy change = reactants - products)#
4. Can you create an energy level diagram to represent this reaction?
H H
H-CEC-H
- H-C-C-H
11
+
2H-H
HH
Prom the table of the values of bond enthalpy, the values we need are:
Bond
Enthalpy (kJ/mol
H-H
432
Сас
239
CH
413
c-c
347
How many π electrons are there in adenine? State which atoms contribute one electron to the π MOs and which atoms contribute two electrons?
Answer:
12 π electrons.
Explanation:
The structure of adenine can be seen below.
From the diagram, the total number of electrons in adenine is 70 electrons where 20 of them are core electrons.
Also from this same structure, we will notice that we have a total number of 12 π electrons.
i.e.
Each one of these five atoms described takes part in the π electron. These are N-1, N-3, N-7 which comprise of 2σ bonds, and also each of three N contributes one π electron.
Similarly, N-9 and N-10 contain 3σ bonds; Hence, each of them donates two electrons.
Thus;
5C = 5π electrons
3N = 3π electrons
2N = 4π electrons
= 12π electrons