Answer:
A heating curve graphically represents the phase transitions that a substance undergoes as heat is added to it. The plateaus on the curve mark the phase changes. The temperature remains constant during these phase transitions.
A solution is known to contain either Ni2 or Cr3 . Addition of what single (1 only) reagent would identify which ion is present?
Answer:
Explanation:
From the periodic table; both elements given are from the same group 3.
To test for which ion will be present in the experiment;
We added 6M aqueous sodium hydroxide in excess.
This process is followed by the addition of hydrogen peroxide H2O2 while stirring.
Heat is then applied to the solution.
After we've carried out those process;
We will notice the following;
If[tex]Ni^{2+}[/tex] is present, then a green [tex]NI(OH)_2[/tex] precipitate will be formed
If [tex]Cr^{3+}[/tex] is present,then a yellow-colored [tex]CrO^{2-}_{4}[/tex] will be formed.
Determine the correct hybridization (from left to right) about each central atom in
CH3CH2OH.
A) 1st C sp3 ; 2nd C sp2 ; O sp B) 1st C sp3 ; 2nd C sp3 ; O sp3
C) 1st C sp ; 2nd C sp2 ; O sp3 D) 1st C sp3 ; 2nd C sp2 ; O sp2
Answer:
B) 1st C sp3 ; 2nd C sp3 ; O sp3
Explanation:
Both carbons in ethanol have an sp³ configuration of their orbitals, given that each carbon atom binds to four other atoms, as can be seen on the extended formula in the attachment.
In these carbons (1st and 2nd) one s orbital and three p orbitals are hybridized to form four hybrid orbitals sp³. These orbitals form four bonds and their bond angles are close to the tetrahedral value of 109.5º,as can be seen for methanol which also has an sp³ configuration.
The oxygen atom can also be described as having sp³ hybrid orbitals. Two of the four hybrid sp³ orbitals in oxygen are occupied by lone electron pairs, and two are used to form bonds with other atoms (in this case the oxygen is bonded to a carbon atom and a hydrogen atom).
Therefore, the three central atoms have an sp³ configuration.
In a coffee-cup calorimeter, 1.60 g of NH4NO3 was mixed with 75.0 g of water at an initial temperature of 25.008C. After dissolution of the salt, the final temperature of the calorimeter contents was 23.348C.
Required:
a. Assuming the solution has a heat capacity of 4.18 J 8C21 g21, and assuming no heat loss to the calorimeter, calculate the enthalpy of solution (DHsoln) for the dissolution of NH4NO3 in units of kJ/mol.
b. If the enthalpy of hydration for NH4NO3 is 2630. kJ/mol, calculate the lattice energy of NH4NO3.
Answer:
Explanation:
mass of the solution m = 1.6 + 75 = 76.6 g
fall in temperature = 25 - 23.34 = 1.66°C
heat absorbed = mass x specific heat x fall in temperature
= 76.6 x 1.66 x 4.18
= 531.5 J .
= .5315 kJ .
mol weight of ammonium nitrate = 80 g
heat absorbed by 1.6 g = .5315 kJ
heat absorbed by 80 g or one mole = 26.575 kJ
enthalpy change ΔH = +26.575 kJ
b )
enthalpy of hydration = 2630 kJ / mol
lattice energy = enthalpy of hydration + enthalpy change
= 2630 + 26.575
= 2656.575 kJ .
Which of the following descriptions best describes a weak base?
A. a base that dissociated completely in water
B. a base that generates a lot of hydroxide ions in water
C. a base that has very low concentration in water
D. A base that dissociates only slightly in water
Answer:
umm.. B. a base that generates a lot of hydroxide ions in water.
The descriptions best describes a weak base is a base that dissociates only slightly in water.
What are bases?Bases are those substances which react with acids to neutralize them, generally bases are the compounds of oxides, hydroxides and carbonates of metal elements.
Bases shows dissocation in the aqueous soluition and pH of bases ranges from 7 to 14. Strong bases shows full dissociation into ions and having higher pH values and weak bases shows partial dissociation into ions & having lower pH values.
Hence, option (D) is correct.
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Balance chemical equation hbr(aq)+o2(g) h20(l)+br2(l)
What elements in group 17 are solids liquids and gass?
Answer: \(\left( \ce{F} \right)\), chlorine \(\left( \ce{Cl} \right)\), bromine \(\left( \ce{Cl} \right)\), iodine \(\left( \ce{I} \right)\), and astatine \(\left( \ce{At} \right)\)
Explanation:
A particular reaction has an enthalpy and entropy of reaction of ∆H = +33 kJ/mol and ∆S = +0.15 kJ/mol⋅K. At the three indicated temperatures, determine if either reactants or products are favored?
Answer:
Explanation: check my paage
how does mass and volume affect sinking and floating? Please don't plagiarize....
Answer:
If an object has a higher density than the fluid it is in (fluid can mean liquid or gas), it will sink. If it has a lower density, it will float. Density is determined by an object's mass and volume. If two objects take up the same volume, but have one has more mass, then it also has a higher density.
Explanation:
An electron in the first energy level of the electron cloud has
an electron in the third energy level.
Answer: A LOWER ENERGY
Explanation:
did the test
Answer:
A lower energy!
Explanation:
I know this is not much of an explanation but I took the test i hope you have an amazing day afternoon or night! Hope this helps :3
a student performed an experiment, using a cocktail peanut, before it was burned the peanut half weighed .353 g. After burning the residue weighed .016 g. The energy released by the conjunction increased the temperature of 200. mL of water in the calorimeter by 7.2 degrees Celsius. Calculate the mass of peanut consumed in the combustion.
What is the density of an object with a volume of 3ml and a mass of 18 grams
Answer:
The answer is 6 g/mLExplanation:
The density of a substance can be found by using the formula
[tex]density = \frac{mass}{volume} \\ [/tex]
From the question we have
[tex]density = \frac{18}{3} \\ [/tex]
We have the final answer as
6 g/mLHope this helps you
Explain how the immune system responds to pathegons
Answer:
The immune system responds to antigens by producing cells that directly attack the pathogen, or by producing special proteins called antibodies. Antibodies attach to an antigen and attract cells that will engulf and destroy the pathogen. The main cells of the immune system are lymphocytes known as B cells and T cells.
Ice, H2O(s), is classified as: An ionic compound, a molecular compound, a homogeneous mixture, a heterogeneous mixture
Answer:
A molecular compound.
Explanation:
An ionic compound is composed of both metal and non-metal elements. Oxygen and hydrogen are both non-metal elements.Any mixture (no matter if it is homogeneous or heterogeneous) is composed of two or more compounds.Ice is simply water in solid form, so it is only one compound. Hence the answer is A molecular compound.Ice, H2O(s), is classified as ; ( B ) A molecular compound
Given that Ice and H₂O are the same element but in different forms therefore we can classify Ice, H₂O as been a molecular compound.
Ice and H₂O are not ionic compounds because ionic compounds are formed between metal and non-metal elements while H₂O and Ice are neither metals but are both Nonmetals
Hence we can conclude that Ice, H2O(s), is classified as A molecular compound
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How something works is related to its structure
Answer:
Forms and Functions
Explanation:
It refers to the direct relationship between the structure of a thing and the way it functions.
Please help me please it due today at 11:00am plz help me
Answer:
Point F
Explanation:
Point F is the maximum potential energy.
Point G is lots of kinetic energy.
Point H is low potenital energy and low kinetic energy.
Question 3. Starting with acetylene
, devise a scheme to prepare 1-chloroheptanol
. There is more
than one way to complete this synthesis
. It can be completed in as few as three reactions. You
can use any alkyl halides as needed as sources of carbon atoms. PLEASE EXPLAIN THE PROCESS. I’m begging. Please.
Answer:
See explanation and image attached
Explanation:
Starting from acetylene, we can react the substrate with methyl iodide in the presence of sodamide and ammonia. We then obtain propyne which then undergoes a similar reaction using butyl iodide to yield 2-heptyne.
This may now be reduced using hydrogen and platinum to yield heptane. Heptane is chlorinated in the presence of light to yield a mixture of products of which 1-chloroheptane is one.
Which of the following is an example of a mixture?
A.
calcium
B.
the atmosphere
C.
carbon dioxide
D.
water
Answer:
B. the atmosphere
Explanation:
hope it helps
What is the kinetic energy of a ball with a mass of 0.5 kg and a velocity of 10 m/s? (Formula:) 25 J 5 J 50 J 100 JWhat is the kinetic energy of a ball with a mass of 0.5 kg and a velocity of 10 m/s? (Formula:) 25 J 5 J 50 J 100 J
Answer:
25J
Explanation:
K.E = 1/2mv^2
= 1/2*0.5*10^2
= 25J
The kinetic energy of the ball is 25 J
What is kinetic energy?Kinetic energy can be defined as the energy possessed by an object in motion. Mathematically, it can be expressed as:
KE = ½mv²
How to determine the kinetic energyFrom the question given above, the following data were obtained:
Mass (m) = 0.5 KgVelocity (v) = 10 m/sKinetic energy (KE) =?KE = ½mv²
KE = ½ × 0.5 × 10²
KE = 0.25 × 100
KE = 25 J
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What can element automatic number tell you about its state of matter
Answer:
Identifies the number of protons a single atom of the element contains.
Explanation:
The atomic number helps people identify elements according to the number of protons one atom of the element has. It essentially defines the element.
While having a neutral charge, it also provides the number of electrons the element has (in one atom).
Which statement is incorrect?
Acids produce H+ ions when ionized.
B. Bases produce OH^ lons when lonized.
C. Bases are found in the pH range of 1-7 on the pH
scale.
Distilled water has a neutral pH of 7.0.
Answer:
C. Bases are found in the pH range of 1-7 on the pH scale.
Explanation:
Acids are less than 7 on the pH scale, so 1-7. Bases are more than 7 on the pH scale, so 7-14. That's why C is incorrect, hope this helps!
Help for chem/physics
Answer:
first and 3rd are ur answers
HURRY
Which part of an atom is mostly empty space?
nucleus
proton cloud
electron cloud
neutron
Answer:
Electron cloud
Explanation:
If you were to scale the size of the atom up to have the nucleus be about the size of a basket ball, then the placement of the actual electrons (about the size of a large marble at this scale) throughout the cloud would be many yards away from the nucleus.
If 35.00 mL of 3.00 M KOH reacted completely (according to our equation), what mass of aluminum has reacted?
Answer:
Explanation:
25 Mass
The mass of the aluminum that has reacted is equal to 2.84 grams.
What is the balanced chemical equation?A chemical equation of a reaction contains of reactants, formed products, and an arrow indicating the direction of the given reaction. The balanced chemical equation in which the number of atoms is equal on either side of the equation. The law of conservation of mass should be followed by a balanced equation.
The chemical equation of the reaction of the KOH and Al is :
[tex]Al + KOH + H_2O \longrightarrow KAl(OH)_4 + H_2[/tex]
From the above equation, we can say that one mole of aluminum is reacting with one mole of KOH.
Given the volume and concentration of KOH are 35 ml and 3.0 M.
The moles of KOH = 3 × 0.035 = 0.105 mol
Therefore, the moles of Al will react = 0.105 mol
The mass of Al will react with KOH = 0.105 × 27 = 2.84 g
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Identify the necessary parts to build a calorimeter. Select one or more:________ A. Cover. B. An interior paper cup. C. Thermometer. D. An interior styrofoam cup. E. An exterior paper cup An exterior styrofoam cup Conductivity probe.
Answer:
Explanation:
A calorimeter is an instrument used for measuring the heat of reactions and heat capacity. A calorimeter should contain an insulating cover, a thermometer, styrofoam cups (you could have that both on the inside and the outside in the case of a styrofoam calorimeter) and you could also have a conductivity probe (in the form of ignition wires and bulb).
A calorimeter is the analytical device used to measure the heat of the reaction. The construction of calorimeter requires cover, paper cup, thermometer, styrofoam cup, and conductivity probe.
How to build a calorimeter?In a chemical reaction, the amount of heat released or absorbed by the reaction helps in the analysis of various parameters. The calorimeter measures the heat of the reaction.
The construction of a calorimeter requires:
Paper can for the filling of water.Cover to stop the loss of heatStyrofoam cup to allow the reactionThermometer to measure the change in temperatureConductivity probe to allow the transfer of heat energyLearn more about calorimeter, here:
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The following concerns the combustion of nitromethane (CH3NO2 - a popular fuel for top-fuel dragsters) according to the reaction below:_______. 2 CH3N02 (1) + ž02(g) → 2C02) + 3H20 (1) + N2(9) a. Burning 121 L of nitromethane at constant pressure releases 1.6 x 100 kJ of energy. What is the enthalpy of combustion of this reaction? The density of nitromethane is 1.16 g/cm². b. Assume you transfer heat involved in the previous problem to 1 kL of water that is initially at 25.0 °C. What is the final temperature of the water?
Answer:
695.8kJ/mol = Enthalpy of combustion
Final temperature = 407.4°C
Explanation:
Taken the reaction:
2CH₃NO₂ + 3/2 O₂ → 2CO₂ + 3H₂O + N₂
The enthalpy of the reaction is the heat released when 1 mole of nitromethane are in combustion.
We need to find the moles presents in 121L of nitromethane using its density and molar mass (61.04g/mol). As these moles releases 1.6x10⁶kJ, we need to find heat released per mole of nitromethane
Mass nitromethane:
121L = 121000cm³ * (1.16g/cm³) = 140360g
Moles:
140360g * (1mol / 61.04g) = 2299.5 moles of nitromethane
Heat released per mole of nitromethane:
1.6x10⁶kJ / 2299.5 mol = 695.8kJ/mol = Enthalpy of combustion
The symbol - is because the heat is released, a + symbol is when the heat is absorbed.
Using:
Q = m×C×ΔT
Where Q is heat (1.6x10⁶kJ = 1.6x10⁹J)
m is mass of water:
1kL = 1000L = 1x10⁶mL = 1x10⁶g
C is specific heat of water: 4.184J/g°C
And ΔT is change in temperature.
Solving for ΔT:
1.6x10⁹J = 1x10⁶g * 4.184J/g°C * ΔT
ΔT = 382.4°C
As initial temperature was 25°C, final temperature is:
382.4°C + 25°C =
407.4°C
What is the hybridization state on the central N atom in the azide ion, N3−?
A student wants to use cookies to make a model of the genetic makeup of the offspring of asexual reproduction. He has vanilla cookies and chocolate cookies available. How can he make his model?
A.
Put chocolate cookies in a row with arrows between them showing the progression from parent to offspring.
B.
Use one chocolate cookie parent with arrows showing that it produces vanilla cookies and chocolate cookies as offspring.
C.
Use chocolate cookies and vanilla cookies as the parents, and vanilla cookies and chocolate cookies as the offspring.
D.
Use chocolate cookies and vanilla cookies as parents, and combine half a vanilla cookie and half a chocolate cookie for the offspring.
Answer:
i am not sure but it seems D is the best
Answer:
A
Explanation:
It seems to be the most logical. My reasoning is that for B when it uses one parent cookie that produced genetically different offspring. That is what makes it incorrect. The other two options involve two parents which means that the reproduction would be sexual. A. would be the closest to the answer.
Please let me know if this is correct! Hope it helped.
Which statement is true?
Adding energy can change a liquid to a solid.
Solids have no movement of molecules.
Liquids do not have a set volume.
Gases can be compressed to change their volume.
Which are the three most common gases Giving Brainliest
Answer:
B
Explanation:
i hope this helps
The sun shines more directly near the equator, bringing more warmth there. In polar regions the sun shines at angles such that
they get little or no sunlight during the winter, causing colder temperatures. Predict how these differences in temperature create a
movement in the atmospheric gases and distribute heat energy from the sun across the planet.
A)
B)
As air in one region diffuses, it becomes less condensed than the
surrounding air and begins to rise and draws more air along.
As air in one region warms, it becomes less dense than the surrounding air
and begins to rise and draws more air in underneath.
As air in one region warms, it becomes less nebulous than the surrounding
air and begins to descend and draws more air in with it.
As air in one region cools, it becomes less compact than the surrounding
air and begins to accelerate and draws more air in supportively.
C)
D)
Answer:Because the Earth is round and not flat, the Sun's rays don't fall evenly on the land and oceans. The Sun shines more directly near the equator bringing these areas more warmth. However, the polar regions are at such an angle to the Sun that they get little or no sunlight during the winter, causing colder temperatures.
Explanation: