Answer:
The shape of a molecule based on the number of electron pairs on the valence shell of its central atom
Explanation:
The improvement of the Sidgwick-Powell theory came to be known as the Valence Shell Electron Pair Repulsion theory (VSEPR). This theory approaches the determination of molecular shape from the perspective of the number of electron pairs on the valence shell of the central atom in the molecule.
Electron pairs on the valence shells of atoms leads to repulsion. Repulsion between two lone pairs is greater than repulsion between a lone pair and a bond pair which is also greater than repulsion between two bond pairs.
Lone pairs cause more repulsion, hence they distort molecules from the ideal shape predicted based on their electron domain geometry.
What combination of substances will give a buffered solution that has a pH of 5.05? (Assume each pair of substances is dissolved in 5.0 L of water.) (Kb for NH3 = 1.8 ´ 10–5; Kb for C5H5N = 1.7 ´ 10–9) Select one: a. 1.0 mole NH3 and 1.5 mole NH4Cl b. 1.5 mole NH3 and 1.0 mole NH4Cl c. 1.0 mole C5H5N and 1.5 mole C5H5NHCl d. 1.5 mole C5H5N and 1.0 mole C5H5NHCl e. none of these
Answer:
c. 1.0 mole C5H5N and 1.5 mole C5H5NHCl
Explanation:
We can determine pH of a buffer using H-H equation:
pH = pKa + log [A⁻] / [HA]
Where [A⁻] is concentration of conjugate base and [HA] concentration of weak acid. These concentrations can be computed as moles of each species.
We need to determine pKa of both NH₃ and C₅H₅N buffers, thus:
pKb = -log Kb
NH₃ pKb = -log 1.8x10⁻⁵ = 4.74
C₅H₅N pKb = -log 1.7x10⁻⁹ = 8.77
And pKa = 14 - pKb:
NH₃ pKa = 14 - 4.74 = 9.26
C₅H₅N pKb = 14 - 8.77 = 5.23
A buffer works only under pH's between pKa-1 and pKa + 1. As pKa NH₃ buffer is 9.23 is not possible to produce a buffer with pH 5.05 for this system.
Thus, we only will compute the buffers made with C₅H₅N:
c. 1.0 mole C5H5N (Weak base) and 1.5 mole C5H5NHCl (Conjugate acid)
pH = pKa + log [A⁻] / [HA]
pH = 5.23+ log [1.0 moles] / 1.5 moles]
pH = 5.05d. 1.5 mole C5H5N and 1.0 mole C5H5NHCl
pH = pKa + log [A⁻] / [HA]
pH = 5.23+ log [1.5 moles] / 1.0 moles]
pH = 5.41Right solution is:
c. 1.0 mole C5H5N and 1.5 mole C5H5NHClExplain how the energy of a toy car is transformed as it slides down a ramp. Give evidence that the energy of the car remains the same at all points on the ramp. (30 points)
Answer:
As the car starts to slide down the ramp, it is kinetic energy and when it's on the top of the ramp, it is potential energy. We can see that the energy is now being transferred through the car and ramp.
how will you measure the length of a curved line by using a thread?
how many oxygen atoms are in 7.25g of calcium nitrate
Answer:
The answer to this question is approximately equal to 1.6 ×
[tex] 1.6 \times {10}^{23} atom \: o[/tex]
156. A solid metal sphere has a volume of 4.2 ft}. The mass
of the sphere is 155 lb. Find the density of the metal
sphere in grams per cubic centimeter.
Answer:
The answer is
0.59 g/cm³Explanation:
To find the density of the sphere we use the formula
[tex]Density \: = \frac{mass}{volume} [/tex]To find the density in g/cm³ first convert the mass into grams and the volume into cm³
For the mass we have
155 lb = 70306.82 g
For the volume
4.2 ft³ = 118930.76 cm³
Substitute the values into the above formula
That's
[tex]Density \: = \frac{70306.82 \: g}{118930.76 \: cm³} [/tex]We have the final answer as
Density = 0.59 g/cm³Hope this helps you
anyone knows how to do this-
Explanation:
The number of protons in the element C^12 (Carbon) is 6, number of electrons 12 and number of Neutrons is 6, same as the number of protons it contains
C^13 has 13 electrons, 6 protons and 7 Neutrons this one's neutron number is different from proton number because it's an isotope
Na^-1 has gained an electron so the number of electrons it has = 24 and the number of protons shown as 11 which means there are 23 - 11 = 12 Neutrons
O^-2 has gained two electrons and got 18 electrons in total, 8 protons and 8 neutrons
How can you use the scientific method in everyday life?
You can use the scientific method everyday by asking questions and doing experiments. For example, you want to know how a fire starts, so you do an experiment with it!
I'll GIVE BRAINLIEST: In a redox reaction, CO is changed to CO2. How many electrons must be lost or gained by C and why?
Answer:
C is gaining 2 electrons
Explanation:
O has a 2- charge so for CO to pick up another O atom would add 2 more electrons.
Answer:
C gains 2 electrons
Explanation:
In the redox reaction, CO is changed into CO2 which means there is an additional oxygen. Oxygen loses 2 of its electrons in order to neutralize. So, C must be gaining 2 electrons in order to make the bond.
3.7500 x 104 + 9.7100 x 105
Answer: [tex]1409.55[/tex]
Remove the 0's from each decimal number
[tex]3.7500 ---> 3.75\\9.7100 ---> 9.71[/tex]
Multiply
[tex]3.75*104=390\\9.71*105=1019.55[/tex]
Add
[tex]930+1019.55=1409.55[/tex]
List the metals Mg, Cu, Au, Na and Al in the decreasing order of their reactivity with air.
Answer:
Na is most reactiveAlcuAu is less reactiveIN HEREAnswer:
Potassium (K)
Sodium (Na)
Calcium (Ca)
Magnesium (Mg)
Aluminium (Al)
Iron (Fe)
Lead (Pb)
Copper (Cu)
Silver (Ag)
Gold (Au)
Plz help me...!!! I need this answer by today!....
What is the weight of a 98 kg astronaut on the Mars where the value of the gravitational pull is 3.711 m/s2?
What is his mass on earth? What is his weight on Venus where the gravitational pull is 8.87 m/s2?
Answer:
Explanation:
given mass on earth =98 kg
gravitational pull on mars =3.711 m/s2
gravitational pull on venus =8.87 m/s2
weight of the body on mars =weight on earth/9.81 m/s2 *3.711 m/s2
W=98 kg*3.711 /9.81m/s2
W=37.07 kg
weight on the venus =weight on earth*8.87 m/s2 /9.81 m/s2
W= 98 kg*7.87 m/s2/9.81 m/s2
W=78.62 kg
tion 1/3
A white rhinoceros weighs about 1,500 pounds (lb). How many tons (T) does the rhinoceros weigh? (1 T =
A. 1.5 T
o
B. 1 T
C. 0.75 T
D. 0.5 T
Answer:
.75 Tons
Explanation:
1 Ton is equal to 2,000 pounds
How would a decrease in volume affect the following reaction? N2 (g) + O2 (g) Two arrows stacked on top of each other. The top arrow points to the right. The bottom arrow points to the left. 2NO(g) (1 point) The equilibrium would shift to the right. The equilibrium would shift to the left. There would be no change to equilibrium. The affect on equilibrium cannot be determined.
Answer:
Explanation:
N₂(g) + O₂(g) ⇄ 2NO( g )
We shall apply Le Chatelier's principle to see the effect of decrease in volume or increase in concentration on the effect of state of equilibrium in the reaction given .
In this reaction 1 volume of nitrogen gas reacts with 1 volume of oxygen to give 2 volume of NO gas . In total there is no change in volume due to reaction . So when we change the volume , the concentration of reactant and product will affect the rate of forward and reverse reaction . Overall there will be no change in the state of equilibrium . The equilibrium will neither shift to the right nor will shift to the left.
It will remain unchanged .
calculate the weight of 3.491 into 10 to the power 19 molecules of cl2
Answer:
The mass of 3.491 × 10¹⁹ molecules of Cl₂ of Cl₂ is 4.11 × 10⁻³ grams
Explanation:
The number of particles in one mole of a substance id=s given by the Avogadro's number which is approximately 6.023 × 10²³ particles
Therefore, we have;
One mole of Cl₂ gas, which is a compound, contains 6.023 × 10²³ individual molecules of Cl₂
3.491 × 10¹⁹ molecules of Cl₂ is equivalent to (3.491 × 10¹⁹)/(6.023 × 10²³) = 5.796 × 10⁻⁵ moles of Cl₂
The mass of one mole of Cl₂ = 70.906 g/mol
The mass of 5.796 × 10⁻⁵ moles of Cl₂ = 70.906 × 5.796 × 10^(-5) = 4.11 × 10⁻³ grams
Therefore;
The mass of 3.491 × 10¹⁹ molecules of Cl₂ of Cl₂ = 4.11 × 10⁻³ grams.
Ou Esaplain different form
of oxygen?
Answer:
oxygen is the chemical element with the atomic number is 8 and the symbol is o its known as called oxygen.
Explanation:
Oxygen is the most third element in the universe at they standard and temperature and pressure,and oxides most elements as other compounds.
Oxygen gas is the earth atmosphere is 21%, an oxygen is the half of the earth crust in form of oxide,oxygen is liquid and solid gas.
Oxygen atoms such as proteins and acids, fats the major organic compounds, oxygen as component of the water and carbon dioxide.
Oxygen has many characteristics :- properties and molecular structure:-
this is a pressure and temperature with molecular formula referred as oxygen,simply describe a double bond and molecular orbits.
Physical properties:- oxygen is highly substance and must be combustible materials, oxygen may also from using a liquid nitrogen coolant, molecular oxygen is the associated with the process of air glow.
Stellar origin :- all of the remaining to half lives to the majority of are less then milliseconds.
Occurrence:- oxygen is the process part of the element in the earth crust, free oxygen is also occurs in the world bodies.
Analysis :- analysis to the structure of vegetation and the carbon cycle on a global scale.
Which of the following elements has a complete outer shell of electrons? A. Iron (Fe) B. Hydrogen (H) C. Neon (Ne) D. Nitrogen (N)
Answer:
The answer is Neon
Answer:
neon
Explanation:
neon has a complete outer 2n shell
What orbits around the nucleus
Answer:
Electrons orbit the nucleus.
Answer:
electrons
Explanation:Atoms are made up of protons and neutrons located within the nucleus, with electrons in orbitals surrounding the nucleus.
How many molecules of sodium oxide will be created if 275 grams of sodium reacts with excess oxygen? Given the equation: 4Na + O2 -> 2Na2O
Answer:
3.60 x 10^24 molecules Na2O
Explanation:
Match the set of measurements of the boiling point of water with the best
description.
Measurements
Description
6. 103 °C, 90 °C, 101 °C
a.
Precise
7. 100 °C, 99 °C, 100 °C
b.
Accurate
8. 105 °C, 106 °C, 105 °C
c. Both accurate and precise
9. 99 °C, 101 °C, 100 °C
d. Neither accurate nor precise
Answer:
Matching
6.D
7.A
8.C
9.B
Explanation:
Took test
103 °C, 90 °C, 101 °C Neither accurate nor precise, 100 °C, 99 °C, 100 °C are Precise, 105 °C, 106 °C, 105 °C are Both accurate and precise, 99 °C, 101 °C, 100 °C are Accurate. These are the correct set of measurements of the boiling point of water.
what are boiling point and melting point ?The melting point is defined as the temperature at which solid and liquid phases are at equilibrium state, whereas the boiling point is defined as the temperature at which the pressure of a vapor of a liquid is equal to the external pressure.
Melting point in which the melting of solid occur to become a liquid at a given temperature, here the molecules gain enough amount of kinetic energy to get the intermolecular forces to convert into another form.
In case of Boiling point the liquid phase enters into the gaseous phase, when the external pressure is high than a temperature for the vapor pressure equal to the external pressure.
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es with hydrogen
atoms
Fill the valencies with
C
+
() C c-c=c
(ii)
(
c
C - C = C
/
c
(ii)
c
- C
با
-
1
c - c
С — С
co
Answer:
all u have to do is inserting hydrogen atoms where it's possible, if carbon is not bonded to any element, then it can have 4 hydrogens. for the first chain, the first carbon can have 3 hydrogen atoms, the second carbon 1 hydrogen atom only the third also 1 hydrogen since there is double bond and the 4th 2 hydrogen atoms
Answer:
a rat and a cat can have sex
xD
Explanation:
HELPPPP Name the three states of matter. Describe the arrangement and movement of atoms in a substance for each state.
Solid, Liquid, and Gas
Solid is the state in which matter maintains a fixed volume and shape; liquid is the state in which matter adapts to the shape of its container but varies only slightly in volume; and gas is the state in which matter expands to occupy the volume and shape of its container.
The states of matter are solid, liquid, and gas. Solid is the state in which matter maintains a fixed volume and shape; liquid is the state in which matter adjusts to the shape of its container but tends to vary only mildly in volume; and gas is the state in which matter expands to occupy the volume and shape of its container.
What is matter?Matter would be any substance with mass and volume that occupies space.
Matter exists in three states: solid, liquid, and gas. The states of matter are solid, liquid, and gas.
Solid is the phase in which matter retains a fixed volume and shape.Liquid is the entity in which matter adjusts to the shape of its container but tends to vary only slightly in volume.Gas is the phase in which matter expands to occupy the volume and shape of its container.Thus, above-mentioned are the three states of matter.
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The substances are placed in separate containers at room temperature, and each container is gradually cooled. Which of these substances will solidify before the temperature reaches 0°C? benzene water butane nitrogen
Answer:
Benzene
Explanation:
You have to find the freezing point for each of these (make sure they're in Celsius). You might want to double check these but:
Benzene: 5.5
Water: 0
Butane: -138
Nitrogen: -210
The substances that will solidify before the temperature reaches 0°C is benzene. The correct option is A.
What is freezing point?Freezing, also known as solidification, is a phase transition that occurs when the temperature of a liquid falls below its freezing point.
If the intermolecular forces between its molecules are strong, the freezing point is high.
When the forces are weak, the freezing point is low. The freezing point of a liquid or the melting point of a solid occurs when the solid and liquid phases are in equilibrium.
Pure benzene has a freezing point of 5.48 degrees Celsius. Because of the salt in it, fresh water freezes at 32 degrees Fahrenheit, but seawater freezes at around 28.4 degrees Fahrenheit.
Thus, as per the given scenario, the correct option is A.
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.hlp me to solve mcq
Answer:
i) b
ii) c
Explanation:
Please see attached picture for full solution.
A balloon is floating around outside your window. The temperature outside is 31 ∘C , and the air pressure is 0.700 atm . Your neighbor, who released the balloon, tells you that he filled it with 4.10 moles of gas. What is the volume of gas inside this balloon? Express to THREE signficant figures.
Answer:
the volume of gas inside this balloon = 146.3 L
Explanation:
Given that:
The temperature T = 31 °C = ( 31 + 273.15 )K = 304.15 K
The air pressure P = 0.700 atm
number of moles of gas n = 4.10 moles
Gas constant = 0.0821 L atm/K/mol
The objective is to calculate the volume of the gas inside the ballon.
Using the Ideal gas equation
PV = nRT
V = nRT/P
V = (4.10×0.0821×304.15)/0.700
V = 102.3799/0.700
V = 146.257 L
V = 146.3 L
Thus, the volume of gas inside this balloon = 146.3 L
If an object's mass is 70 g, and its volume is 10cm cubed, what is its density?
If an object's mass is 70 g, and its volume is 10cm cubed, its density is 7 centimeter cube.
What is density?The density of any solid substance is the unit of the area occupied by it in per centimeter of the cube of the volume in the given sample and calculated by dividing the mass and the volume of the compound unit will be centimeter cube.
The mass of the given object is 70 gram and the volume is given is 10 cm to find the density,
Density = mass of object / volume of object
substituting the value in the formula,
Density = 70 / 10
Density = 7 centimeter cube.
Therefore, the density of the given object will be 7 centimeter cube if an object's mass is 70 g, and its volume is 10cm cubed.
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An element’s most stable ion forms an ionic compound with bromine, having the formula XBr2. If the ion of element "X" has a mass number of 230 and has 86 electrons, what is the identity of the element, and how many neutrons does it have?
Answer:
88
Explanation:
The ion has a charge of 2+, therefore the number of neutrons it possess is 86+2
which equals 88
The element X having a mass number of 230 and has 86 electrons is radium and has 142 neutrons.
An atom is composed basically of electrons, protons and neutrons. In a neutral atom, the number of protons and electrons are equal. The number of neutrons is the difference between the mass number and the number of protons (atomic number).
Since we know that the ion of the element X has 86 electrons and the compound formed is XBr2, it then means that neutral X has 88 electrons.
The number of electrons in the neutral atom is the same as the number of protons or atomic number. An element can be identified by its atomic number. The element having atomic number 88 is radium.
The number of neutrons is obtained as;
Mass number - atomic number
230 - 88 = 142 neutrons
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A sample of copper is heated to 100°C and placed into a calorimeter containing 50 g of water at 25°C after a few minutes the final temperature of the system reaches 40°C how much heat in joules was released by the copper Sample
Answer:
Heat = 3138J
Explanation:
In the system, the sample of Copper is releasing heat that produce the increasing in the temperature of water.
Using the equation of calorimeter, we can find the heat released for the sample of copper (The same that is absorbed for the water):
Q = C×m×ΔT
Where Q is heat, C is specific heat (For water: 4.184J/molK), m is the mass of water (50g) and ΔT is change in temperature of water (40°C-25°C = 15°C)
Replacing:
Q = 4.184J/molK×50g×15°C
Q = 3138J is the heat released for the sample of Copper (The same absorbed for the water).
Answer:
heat=3138j
Explanation:
In the system, the sample of Copper is releasing heat that produce the increasing in the temperature of water.
Using the equation of calorimeter, we can find the heat released for the sample of copper (The same that is absorbed for the water):
Q = C×m×ΔT
Where Q is heat, C is specific heat (For water: 4.184J/molK), m is the mass of water (50g) and ΔT is change in temperature of water (40°C-25°C = 15°C)
Replacing:
Q = 4.184J/molK×50g×15°C
Q = 3138J is the heat released for the sample of Copper (The same absorbed for the water).
HELP!!!!!!, I need this urgently!!!
Compare the properties of producer and water gas
Answer:
Producer gas and water gas contain carbon monoxide and hydrogen.
What would be the pH of an HNO3 solution if the [H+] = 3.26 x 10-6 moles/liter? 5.49 4.67 6.32
Answer:
5.49
Explanation:
pH = - log[3.26 x 10-6] =5.49
the overall take away of an experiment’s results is the______. A. hypothesis B. introduction C. conclusion
Answer:
conclusion
Explanation:
it can't be a hypothesis since tests are carried out to verify so it is not a theory
an introduction to an experiment only gives the basis of what we are investigating therefore nothing has been proven and the question is still unanswered
The overall takeaway of an experiment’s results is the conclusion. Hence, option C is correct.
What is a hypothesis?A hypothesis is a testable statement about the relationship between two or more variables or a proposed explanation for some observed experiment.
The overall takeaway of an experiment’s results can't be a hypothesis since tests are carried out to verify so it is not a theory
An experiment only gives an idea about the investigation therefore nothing has been proven and the question is still unanswered.
Hence, the overall takeaway of an experiment’s results is the conclusion.
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