Answer:
B. Similar fossils were found in different continents.
Answer:
B. Similar fossils were found in different continents.
Explanation:
How many moles of hydrogen react with 4.5 moles of oxygen to synthesize water?
Answer:
9moles of hydrogen gas
Explanation:
To solve this problem, we write the reaction expression first;
2H₂ + O₂ → 2H₂O
We have been given the number of moles of oxygen gas to be:
Number of moles of oxygen gas = 4.5moles
From the balanced reaction expression:
1 mole of oxygen gas reacts with 2 moles of hydrogen gas
4.5moles of oxygen gas will react with 4.5 x 2 = 9moles of hydrogen gas
A certain substance X condenses at a temperature of 123.3°C . But if a 650. g sample of X's prepared with 24.6 g of urea ((NH2)2 CO) dissolved in it, the sample is found to have a condensation point of 124.3°C instead. Calculate the molal boiling point elevation constant Kb of X.
Answer:
1.6 °C.kg/mol
Explanation:
Step 1: Calculate the molality of urea
We will use the following expression.
m = mass(urea) / molar mass(urea) × kg solvent
m = 24.6 g / 60.06 g/mol × 0.650 kg
m = 0.630 mol/kg
Step 2: Calculate the boiling point elevation of X
The boiling point elevation is a colligative property that can be calculated using the following expression.
ΔTb = 124.3 °C - 123.3 °C = 1.0 °C
Step 3: Calculate the boiling point elevation constant
We will use the following expression.
ΔTb = Kb × m
Kb = ΔTb/m
Kb = 1.0 °C/(0.630 mol/kg) = 1.6 °C.kg/mol
what are some sources of error associated with electroplating
Answer:
Cold Shuts. Cold shuts are one of the most common defects found in materials sent for electroplating.
Pitting
Sharp Edges
Cleavage Points
Unclean Manufacturing
Loss of Adhesion
Cracking After Plating — Hydrogen Cracking
Dull and Hazy Deposits in Plating.
Explanation:
Which of the following has the largest atomic radius?
Answer:
b
Explanation:
What is the mass of 3.00 -1023 particles of water? Water has a molar mass of 18.0 g/mol.
3.00 grams
18.0 grams
6.00 grams
9.00 grams
Answer:
bro
Explanation:
guhfuyfouyvyu
Answer:
9.00
Explanation:
I took the test and got it correct ...
identified the nucleus that is found in an item that has a stable valance electron configuration
Answer:
Nucleus 3 i believe
To solve the ultraviolet catastrophe, Planck applied quantization to: Select the correct answer below:
A. vibrational energies of atoms
B. orbital energies of electrons
C. kinetic energies of photons
D. temperature of the system
Answer:
Vibrational energies of atoms
Explanation:
Planck applied quantization to Vibrational energies of atoms because in Black body spectrum prediction a blackbody at equilibrium is expected to radiate energies at various Frequencies ( i.e. increase in radiated energy ∝ increase in frequency ) but towards the ultraviolet region of the spectrum the energy radiated begins to drop as frequency increases. The phenomenon of drop in energy with increase in frequency is termed Ultraviolet catastrophe. hence to solve this phenomenon Planck applied quantization to Vibrational energies of atoms
Which element in group 17 has the highest ionization energy
Answer:
fluorine
Explanation:
it has the highest electronegativity in the group and in the periodic table
Bond length is the distance between the centers of two bonded atoms. On the potential energy curve, the bond length is the internuclear distance between the two atoms when the potential energy of the system reaches its lowest value. Consider that the atomic radius (sometimes called the covalent or bonding atomic radius) of an element is defined as one-half the distance between the bonded atoms in a homonuclear diatomic molecule. Actual bond lengths in molecules are determined experimentally by such methods as X-ray diffraction and microwave spectroscopy. However, these atomic radii values can be used to give an estimate of the upper limit of bond length in other (heteronuclear) molecules. Given that the atomic radii of H and Br are 37.0 pm and 115 pm , respectively, predict the upper limit of the bond length of the HBr molecule.
Answer:
152 pm
Explanation:
According to the question, we can estimate the bond length from the given values of the atomic radii. This now is the upper limit of the bond length for the molecule.
Since we have that;
Atomic radius of H= 37.0 pm
Atomic radius of Br = 115.0 pm
Bond length = Atomic radius of H + Atomic radius of Br
Bond length = 37.0 pm + 115.0 pm
Bond length = 152 pm
helpppp nowwww plssss!!!
Answer: B
Explanation:
A catalyst decreases the activation energy of a particular exothermic reaction by 56 kJ/mol, to 35 kJ/mol. Assuming that the mechanism has only one step, and that the products are 78 kJ lower in energy than the reactants, sketch approximate energy-level diagrams for the catalyzed and uncatalyzed reactions. What is the activation energy for the uncatalyzed reverse reaction
Answer:
Activation energy for the uncatalyzed reverse reaction = 103 kJ/mol
Explanation:
Activation energy decreases from = 56 kj/mol to 35 kj/mol
products = 78 KJ lower in energy than reactants
Activation energy for the uncatalyzed reverse reaction = 103 kJ/mol
attached below are the sketches of approximate energy-level for both catalyzed and uncatalyzed reactions
When 70.4 g of benzamide (C7H7NO) are dissolved in 850. g of a certain mystery liquid X, the freezing point of the solution is 2.7 C lower than the freezing point of pure X. On the other hand, when 70.4 g of ammonium chloride (NH CI) are dissolved in the same mass of X, the freezing point of the solution is 9.9 °C lower than the freezing point of pure X.
Required:
Calculate the van't Hoff factor for ammonium chloride in X.
Answer:
1.62
Explanation:
From the given information:
number of moles of benzamide [tex]=\dfrac{70.4 \ g}{121.14 \ g/mol}[/tex]
= 0.58 mole
The molality = [tex]\dfrac{mass \ of \ solute (i.e. \ benzamide )}{mass \ of \ solvent }[/tex]
[tex]= \dfrac{0.58 }{0.85 }[/tex]
= 0.6837
Using the formula:
[tex]\mathbf {dT = l \times k_f \times m}[/tex]
where;
dT = freezing point = 27
l = Van't Hoff factor = 1
kf = freezing constant of the solvent
∴
2.7 °C = 1 × kf × 0.6837 m
kf = 2.7 °C/ 0.6837m
kf = 3.949 °C/m
number of moles of NH4Cl = [tex]\dfrac{70.4 \ g}{53.491 \ g /mol}[/tex]
= 1.316 mol
The molality = [tex]\dfrac{1.316 \ mol}{0.85 \ kg}[/tex]
= 1.5484
Thus;
the above kf value is used in determining the Van't Hoff factor for NH4Cl
i.e.
9.9 = l × 3.949 × 1.5484 m
[tex]l = \dfrac{9.9}{3.949 \times 1.5484 \ m}[/tex]
l = 1.62
GRADE 5 SCIENCE MYA-2020-2021
Testosters are testing the choict of light on a radiometer Team 1 finds that blue light makes the radiometer spin slower when a blue light is 35 centimeters (cm) away. To validate Team 1's test results, how must
Text with and that is 20 cm away
Test what that is 45 cm away
Test with a green light that is 40 cm away
Test with the light that is 35 cm away
Answer:
Test it with a blue light that is 45 cm away.
Explanation:
A copper wire is 44.85 cm long and weighs 1.521 g. The density of copper is 8.933 g/cm3.
What is the radius of the wire in millimeters?
What is the diameter of the wire?
Answer:
i am so sorry
Explanation:
The density of copper is If a sample 8.933 g/cm3. If copper has a volume of 12.993 cm^3. Then the mass will be 136.29 gram.
How can we calculate the mass from density and volume?Density is defined as the mass per unit volume it means that mass present in 1 meter cube is called density. The S.I unit of density is kg/m^3 and in C.G.S it is gram/cm^3
So, In above question can understand that density, mass, and volume all are convert to each other it means that if we know any two variable then third one will be calculated easily.
Mathematically,
Formula for density will be as mentioned below:-
Density = Mass/Volume.
From above formula we can calculate mass which is as follows:-
Mass = Volume × Density.
S.I unit of mass is kilograms and C.G.S unit is gram.
So In above question
Density = 8.933 gram/cm^3
Volume = 12.993 cm^3
So from above formula
Mass = Density × volume
= 10.49 × 12.993
= 136.29 gram
= 0.13629 kilogram
So Mass is equal to 136.29 gram or 0.136 kilograms.
Therefore,The density of copper is If a sample 8.933 g/cm3. If copper has a volume of 12.993 cm^3. Then the mass will be 136.29 gram.
Learn more about density here:
https://brainly.com/question/15164682
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What type of rock is limestone? Describe how a limestone rock is likely to change over a long period of time. Pls answer I will mark brainiest.
What type of rock is limestone? Describe how a limestone rock is likely to change over a long period of time. Pls answer I will mark brainiest.
Answer:Sedimentary Rock Limestone being a sedimentary rock would be converted to marble, a metamorphic rock if subjected to metamorphic conditions over an extensive period of time. Over a long period of time, we would take a look at the rock "limestone" through the rock cycle.#CARRYONLEARNING #STUDYWELLYou'll be given 100 points if you answer this question!!!!!!!!!!!!
3.
What do we call materials
that let heat pass through
them easily?
Thermal conductors
Thermal insulators
Transparent
4.
Which of these is a good
thermal conductor?
Plastic
Wood
Steel
5.
Which of these is a good
thermal insulator?
Steel
Iron
Polystyrene
6.
To save on heating bills, do
you think the roof of a
building should be lined with
a thermal conductor
a thermal insulator
nothing
7.
How does heat travel?
From cold things to hotter things
From hot things to colder things
Between things of the same temperature
Answer:conducts ,steel, polystyrene, thermal insulation
Explanation:
Which of the following is a list of the minimum amount of data needed for determining the molar enthalpy of solution of KCl(s) in pure H2O(1) ? (Assume that the KCl(aq) has the same specific heat capacity as pure water and that the initial temperatures of the KCl(s) and the water are the same.)
(A) Mass of KCl(s), initial temperature of the water, and final temperature of the solution
(B) Mass of H20, initial temperature of the water, and final temperature of the solution
(C) Mass of KCl(s), mass of H20, initial temperature of the water, and final temperature of the solution
(D) Mass of KCl(s), mass of H20, initial temperature of the water, final temperature of the solution, and atmospheric pressure
Answer:
(C) Mass of KCl(s), mass of H20, initial temperature of the water, and final temperature of the solution
Explanation:
molar enthalpy of solution of KCl(s) is heat evolved or absorbed when one mole of KCl is dissolved in water to make pure solution . The heat evolved or absorbed can be calculated by the following relation.
Q = msΔt where m is mass of solution or water , s is specific heat and Δt is change in temperature of water .
So data required is mass of water or solution , initial and final temperature of solution , specific heat of water is known .
Now to know molar heat , we require mass of solute or KCl dissolved to know heat heat absorbed or evolved by dissolution of one mole of solute .
The correct option is option C.
To determine the molar enthalpy of the solution of [tex]Kcl(s)[/tex] is pure [tex]H_2O(l)[/tex]
We need to know that the,
grams of [tex]Kcl(s)[/tex] grams of [tex]H_2O[/tex] Initial temperature of [tex]H_2O[/tex] The final temperature of the solution.Learn More:https://brainly.com/question/25758173
Which factors directly affect the magnetic force produced by an electromagnet?
O number of turns in the wire, amount of current
O amount of current, type of force
O length of core, number of turns in the wire
O amount of current, length of core
You can use solid, wedged, and dashed lines to better represent the 3D structure of molecules. The solid lines represent bonds in the plane of the paper, wedged lines represent a bond coming out of the plane, and the dashed line represents a bond going back behind the plane of the paper. Draw a representation of methane that better depicts its 3D structure.
Answer:
See explanation and image attached
Explanation:
Often times, there is a need for a three dimensional representation of a molecule on paper. These three dimensional representations give us an idea of what the molecule really looks like if we were to be looking at it physically.
In order to make a three dimensional representation, we use wedged and dashed bonds. The wedged bonds are coming out of the plane of the paper towards you while the dashed bonds are going into the plane of the paper away from you.
In the image attached, you will find the three dimensional representation of the methane molecule.
Why do organisms eat food? Be sure to explain your answer.
Answer:
Organisms need to take food to get energy and perform life processes. A living organism undergoes many life processes like nutrition, respiration, digestion, transportation, excretion, circulation of blood, and reproduction. To perform all these life processes the organism needs energy and nutrients.
Explanation:
nnastarannnn his idea
100%
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Merriweath...
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6. What is the mass, in grams, of 1.92 moles of Ca(OH),?
Answer:
Mass = 142.25 g
Explanation:
Given data:
Mass of Ca(OH)₂ = ?
Number of moles of Ca(OH)₂ = 1.92 mol
Solution:
Formula:
Mass = number of moles × molar mass
Molar mass of Ca(OH)₂ = 74.09 g/mol
by putting values,
Mass = 1.92 mol × 74.09 g/mol
Mass = 142.25 g
Ammonium phosphate is an important ingredient in many solid fertilizers. it can be made by reacting aqueous phosphoric acid with liquid ammonia. calculate the moles of ammonium phosphate produced by the reaction of 0.085 mol of ammonia. be sure your answer has a unit symbol, if necessary, and round it to the correct number of significant digits.
Answer:
0.028 mole of ammonium phosphate, (NH₄)₃PO₄.
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
H₃PO₄ + 3NH₃ —> (NH₄)₃PO₄
From the balanced equation above,
3 moles of NH₃ reacted to produce 1 mole of (NH₄)₃PO₄.
Finally, we shall determine the number of mole of (NH₄)₃PO₄ produced by the reaction of 0.085 mole of ammonia, NH₃. This can be obtained as follow:
From the balanced equation above,
3 moles of NH₃ reacted to produce 1 mole of (NH₄)₃PO₄.
Therefore, 0.085 mole of NH₃ will react to produce = (0.085 × 1)/3 = 0.028 mole of (NH₄)₃PO₄.
Thus, 0.028 mole of ammonium phosphate, (NH₄)₃PO₄ were obtained from the reaction.
PLEASE HELP BRAINLIEST AND 15 points.
1. Which substance is nonvolatile ?
(1.5 Points)
Substance B, boiling point of 105 °C
Substance C, boiling point of 25 °C
Substance A, boiling point of 75 °C
Substance d, boiling point of 45 °C
Answer:
Substance B, boiling point of 105 °C
Explanation:
Non volatile substances have high boiling points
Which statement is always true about conversation of matter?
The mass of a system does not change during a chemical reaction
If a solid forms the mass of a system increases
If a gas forms the mass of a system decreases
The mass of a system changes when a substance changes from liquid to gas, but it does not change in a chemical reaction
Answer:
The mass of a system does not change during a chemical reaction
Explanation:
Correct Answers
PLS HELLPPPP
Which of the following objects would have the greatest gravitational attraction between them if they were set 3.0 km apart?
A .20kg object and a 200kg object
A 10kg object and a 100kg object
A 30kg object and a 200,000kg object
A 400,000 kg object and a 100,000,000kg object
Answer:
A 400,000 kg object and a 100,000,000kg object
Explanation:
The objects with the most mass between them will have the greatest gravitational attraction.
This is why the last option is the right choice.
The reason for this is based on the Newton's law of universal gravitation which states that:
"the gravitational force of attraction between two bodies is directly proportional to the product of their masses and inversely proportional to the square of the distance between them".
So, the more the mass, the greater the gravitational attraction between two bodies.
If you have 3.5 L of He to blow up balloons... at STP...
a) How many moles of He do you have?
b) How many grams of He do you have?
Answer:
B
Explanation:
A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force. Let us take it that the force acts on the object through the displacement. What is the work done in this case?
Answer:
56 J
Explanation:
Step 1: Given data
Force applied on the object (F): 7 NDisplacement of the object (d): 8 mStep 2: Calculate the work (w) done on the object
We can find the work done on the object using the following expression.
w = F × d × cosθ
where
θ is the angle between F and d
Since F and d occur in the same direction, θ = 0° and cosθ = 1. Then,
w = F × d × 1
w = F × d
w = 7 N × 8 m = 56 J
Classify each as acidic or basic - pH 9 - pH 2.3 - pH 11 - pH 5 - solution where the concentration of hydronium ions [H ] is 0.0056 M - solution where the concentration of hydronium ions [H ] is 3.45 E-9 M.
Answer:
pH = 9: Basic; pH = 2.3: acidic; pH = 11: basic; pH = 5: Acidic; [H⁺] = 0.0056M: Acidic; [H⁺] = 3.45E-9M: Basic
Explanation:
A solution is defined as acidic when pH < 7 and as basic when pH > 7.
Also, pH = -log[H⁺].
Thus:
pH = 9: >7 → Basic
pH = 2.3: <7 → Acidic
pH = 11: >7 → Basic
pH = 5: <7 → Acidic
[H⁺] = 0.0056M, pH = -log0.0056M = 2.25: <7: Acidic
[H⁺] = 3.45E-9M, pH = 8.46: > 7: Basic
100 POINTS FOR BEST ANSWER! What is the difference between LDOF and SDOF
An SDOF system is one whose motion is governed by a single, second-order differential equation. Only two variables, position and velocity are needed to describe the trajectory of the system. Many structures can be idealized as single degree-of-freedom systems.
The LDAP Data Interchange Format is a standard plain text data interchange format for representing LDAP directory content and update requests. LDIF conveys directory content as a set of records, one record for each object.
What is the mass of 1.75 moles of Ca(H2C302)2?
Explanation:
first we have to find molar mass of ca(H2c3o2)2
40+(1*2)2+(12*3)2+(16*2)2
40+4+72+64=180g/mole
m=n*Mm
m=1.75mole*180g/mole
m=315g
