Answer:
D. 25 grams
Explanation:
I think that's what the answer is
Determine the number of moles in a sample of 2.82g B
Answer:
0.123 mol
Explanation:
1 mol Na/22.99g na=0.123 mol
Answer:
[tex]\boxed {\boxed {\sf 0.261 \ mol \ B}}[/tex]
Explanation:
We are asked to find the number of moles in a sample of 2.82 grams of boron.
We convert grams to moles using the molar mass or the mass of 1 mole of a substance. These values are found on the Periodic Table. They are equivalent to the atomic masses, but the units are grams per mole instead of atomic mass units.
Look up the molar mass of boron (B).
B: 10.81 g/molConvert using dimensional analysis. Set up a conversion factor using the molar mass.
[tex]\frac {10.81 \ g \ B}{ 1 \ mol \ B}[/tex]
We are converting 2.82 grams of boron to moles, so we multiply by this value.
[tex]2.82 \ g \ B *\frac {10.81 \ g \ B}{ 1 \ mol \ B}[/tex]
Flip the ratio so the units of grams of boron cancel.
[tex]2.82 \ g \ B *\frac { 1 \ mol \ B}{10.81 \ g \ B}[/tex]
[tex]2.82*\frac { 1 \ mol \ B}{10.81}[/tex]
[tex]\frac {2.82}{10.81} \ mol \ B[/tex]
[tex]0.2608695652 \ mol \ B[/tex]
The original value of grams has 3 significant figures, so our answer must have the same. For the number we found, this is the thousandth place. The 8 in the ten-thousandth place tells us to round the 0 up to a 1.
[tex]0.261 \ mol \ B[/tex]
There are approximately 0.261 moles of boron (B)in 2.82 grams of boron.
what classifies materials as a pure substance or a mixture
Answer:
A pure substance is a form of matter that has a constant composition and properties that are constant throughout the sample. Mixtures are physical combinations of two or more elements and/or compounds.
In the following reaction, how many liters of oxygen will react with 270 liters of ethene (C2H4) at STP?
C2H4(g) + 3O2(g) 2CO2(g) + 2H2O(g)
The volume of one mole of gas at STP is 22.4 liters.
how many grams of hydrogen in 1.85moles
Alka-Seltzer is pure NaHCO3
True or false?
Answer:
falso
Explanation:
C3h8+o2=co2+h2o balance the equation
A line can be used to represent a covalent bond between two atoms. Diagram pairs of atoms
that can form single, double, and triple bonds.
Can every atom form each of these kinds of bonds?
The covalent bond has been formed by the atom with the difference in the electronegativities and the presence of loan pair for an unsaturated bond.
The covalent bond has been formed between the atoms when there has been the sharing of electrons. The presence of loan pairs results in the formation of pi bonds, which are unsaturated covalent sharing formed above or below the covalent bonds.
An example of pair with a single bond has been:
H-HO-OThe examples of pairs with double bonds:
HHC=CHHC=OThe examples of pairs with triple bonds:
N [tex]\equiv[/tex] NHC [tex]\equiv[/tex] CHNot every atom can form these bonds as there has been the presence of loan pairs with the atom for the formation of the double and triple bond.
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What is condensation
PLS HELP WORTH 25 POINTS WILL MARK BRAINLIEST IF CORRECT
Examine the false statement. When pressure is added to a reaction at chemical equilibrium, the reaction responds by increasing the amount of pressure it exerts on its surroundings. Select the rewording that makes the statement true.
A. When pressure is added to a reaction at chemical equilibrium, the reaction responds by increasing the rate of reaction, which will decrease the number of particles and offset the pressure.
B. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it exerts on its surroundings.
C. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by increasing the rate of reaction, which will decrease the number of particles and increase the pressure.
D. When pressure is removed from a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it releases to its surroundings.
E. When pressure is added to a reaction at chemical equilibrium, the reaction responds by decreasing the amount of pressure it absorbs from its surroundings.
IT'S NOT C OR E
Answer:
A i think. Good luck!!!!
What would be the product when combustion reaction occurs in a small tightly-closed container?
Answer:
Incomplete combustion produces carbon monoxide along with some carbon dioxide. Water is always produced during combustion. If the fuel is sulfur containing, carbon disulfide will result as well.
Have a happy day! <3Miss Hawaii
Explanation:
Which of the following is a salt?
C6H12O6
O2
C2H2
K C l
Answer:
it's kcl
Explanation:
the kcl should be salt
A car is accelerated at a rate of 2.5 meters/second?. If the starting speed is 5.0 meters/second, how
many seconds will it take the car to reach a final speed of 27.0 meters/second?
Answer:
8.8 seconds
Explanation:
Formula: acceleration = (v - u) /t where v = final velocity, u = initial velocity and t = time
a = 2.5 m/s²
u = 5.0
v = 27. 0
t =?
at = v - u
t = (v - u) /a
= (27- 5)/ 2.5
= 8.8 s
The electronic transition in a hydrogen atom from n = 7 to n = 2 emits electromagnetic radiation having a longer wavelength than a transition from n = 6 to n = 3.
Answer: I'll leave the answer rounded to three sig figs.
mark me brainlist
So, you can say that in a hydrogen atom, an electron located on
n
i
=
2
that absorbs a photon of energy
4.85
⋅
10
−
19
J
can make the jump to
n
f
=
6
.
Explanation:
The question wants you to determine the energy that the incoming photon must have in order to allow the electron that absorbs it to jump from
n
i
=
2
to
n
f
=
6
.
A good starting point here will be to calculate the energy of the photon emitted when the electron falls from
n
i
=
6
to
n
f
=
2
by using the Rydberg equation.
5. A student measures the mass of an object three times on a balance in order to calculate the objects
density. The recorded masses are 70.21 g, 64.55 g, and 74.70 g. The accepted value for the mass of
the object is 70.21 g.
a. Are these measurements accurate? Why or why not?
b. Are the measurements precise? Why or why not?
Answer:
This is not chemistry this is physics
What is the mass of some honey that has a volume of 120.8 fl oz and a density of 1.38 kg/L?
Answer:
166.704
Explanation:
Using the provided table and the equation below, determine the heat of formation (in kJ/mol) for CuBr₂.
CuCl₂ (s) + Br₂(l) → CuBr₂ (s) + Cl₂ (g) ∆H° = 64.1 kJ/mol
CuCl2= -205.9 kJ/mol
Br2= 0 kJ/mol
Cl2= 0 kJ/mol
The heat of formation of CuBr₂ (s) = -141.8 kJ/mol
The heat of reaction ΔH = ∑ΔHproducts - ∑ΔHreactants
ΔH = ΔHCuBr₂ (s) + ΔHCl₂ (g) - [ΔHCuCl₂ (s) + ΔHBr₂(l)]
where ΔHCuBr₂ (s) = heat of formation of CuBr₂ (s), ΔHCl₂ (g) = heat of formation of Cl₂ (g) = 0 kJ/mol, ΔHCuCl₂ (s) = heat of formation of CuCl₂ (s) = -205.9 kJ/mol, ΔHBr₂(l) = heat of formation of Br₂(l) = 0 kJ/mol and ΔH = heat of reaction = 64.1 kJ/mol
Substituting the values of the variables into the equation, we have
ΔH = ΔHCuBr₂ (s) + ΔHCl₂ (g) - [ΔHCuCl₂ (s) + ΔHBr₂(l)]
64.1 kJ/mol = ΔHCuBr₂ (s) + 0 kJ/mol - [-205.9 kJ/mol + 0 kJ/mol]
64.1 kJ/mol = ΔHCuBr₂ (s) + 0 kJ/mol + 205.9 kJ/mol - 0 kJ/mol
64.1 kJ/mol = ΔHCuBr₂ (s) + 205.9 kJ/mol
ΔHCuBr₂ (s) = 64.1 kJ/mol - 205.9 kJ/mol
ΔHCuBr₂ (s) = -141.8 kJ/mol
So, the heat of formation of CuBr₂ (s) = -141.8 kJ/mol
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When the Northern Hemisphere is tilted ________the Sun, the sunlight is _________ direct than it is in the Southern Hemisphere. (Select all that apply.)
away from; less
toward; more
toward; less
away from; more
toward, more
away from, less
Explanation:
When the northern hemisphere is tilted toward the sun, the sunlight is more direct than it is in the southern hemisphere. This explains why it's wintertime in Australia while at the same time, it's summertime in the US.
When the northern hemisphere is tilted away from the sun, the sunlight is less direct than it is in the southern hemisphere. This explains why it's summertime in Australia while it's wintertime in the US.
Please answer question (e)
Answer:
I don't know sorry am read in 5 class
Summarize the steps of water cycle
Answer:
The water cycle consists of three major processes: evaporation, condensation, and precipitation. Evaporation is the process of a liquid's surface changing to a gas. In the water cycle, liquid water (in the ocean, lakes, or rivers) evaporates and becomes water vapor.
Explanation:
Name the following compound and tell what type of compound it is: Protons 6, Neutrons 8, and electrons 6
Answer:
Carbon-14
Explanation:
It's carbon, because the element has 6 proton.
It's not an ion, because there are same number of proton and electron 6=6
It is carbon-14 because 6 proton + 8 neutron = 14
What is the molarity of a solution that contains 0.505 mol KCl (molar mass = 74.55 g/mol) in 7.98 L of solution?
Answer:c
=
0.0253 M
Explanation:
Molarity is a measure of a solution's concentration in terms of how many moles of solute it contains per liter of solution.
So, in essence, if you have the number of moles of solute, like you do here, and the total volume of the solution expressed in liters, you can find how many moles of solute you get per liter, i.e. the molarity of the solution.
Keeping in mind the fact that the moles of solute are distributed evenly in any given volume of the solution, you can say that because
7.98 L
of solution contain
0.202
moles of solute, which in your case is potassium chloride,
KCl
,
1 L
of this solution will contain
1
L
⋅
0.202 moles KCl
7.98
L
=
0.0253 moles KCl
So, if your solution contains
0.0253
moles of potassium chloride per liter, it follows that its molarity is equal to
c
=
0.0253 M
Here
M
is equivalent to
mol/L
, or molar.
The molarity of the solution that contains 0.505 mol KCl in 7.98 L of the solution is 0.0632 moles/L.
What is called the Molarity of a solution?Molarity is a measure of a solution concentration in terms of how many moles of solute it contains per liter of solution.
Molarity = Moles of solute / Liters of solution
Its unit is mole/L
Calculating the molarity of the given solution:Given that a solution contains 0.505 mol KCl in 7.98 L of solution
Moles of solute (KCl) = 0.505 mol
Liters of solution = 7.98 L
Then, the molarity will be
M = [tex]\frac{0.505}{7.98}[/tex]
= 0.0632 moles/L
Therefore, the molarity of the given solution is 0.0632 moles/L.
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Si un átomo tiene 18 electrones, cuántos protones tiene?
Answer:
huhhhhhhhhj
hshshhshshshshshsh
Which circle contains the mixture? Is it D?
A total solar eclipse occurs because the moon can totally block the sun. If the moon was smaller or farther from earth, a total eclipse
Could occur
Could not occur
Answer:
both
Explanation:
id say that it could occur but also not as much. the moon would be smaller and further from the earth to where we would barely be able to see it. if the full moon is barely visible then im sure the total solar eclipse wouldn't be as noticeable as it is now. but thats just my opinion
How many atoms are in 1.27 mol of pure aluminum?
Answer:
To determine the amount of atoms (or molecules) present given the moles of an element, you multiply the amount of moles by Avogadro's number,
6.022
⋅
10
23
4 mol
A
l
6.022
⋅
10
23
1
m
o
l
=
2.41
⋅
10
24
atoms/molecules of
A
l
Explanation:
Are the atoms really "sharing" electrons? Explain.
Answer:
yes, in certain cases
there are different types of bondings between atoms
and in some they lend electrons to make their atom stable this type of bonding is called ionic bonding
and in covalent bond the atoms share their electrons
If a aluminum cube had a mass of 20g and the length of each side was 2cm between what to liquids would it float?
Answer:
density=20/8 g/cc=2.5 g/cc
Mercury is more dense, so aluminum will float on it. Water is less dense, so the aluminum will be below water.
Aluminum will float atop mercury because it is more dense than it. Due to water's lower density, the metal will lie below the surface.
What is density?Density is defined as the measure of how densely a material is packed together.
It can also be defined as the mass of a solid substance per unit volume.
Density is important because it enables us to predict which compounds will float and which will sink in a liquid, density is a crucial notion. As long as an object's density is lower than the liquid's density, it will often float.
The term "density" refers to the relationship between a substance's mass and the volume it takes up in space. The mass, size, and arrangement of an object's atoms influence its density.
Density can be expressed as
Density = mass / volume
There are two types of density.
Absolute densityRelative densityThus, aluminum will float atop mercury because it is more dense than it. Due to water's lower density, the metal will lie below the surface.
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<
Time's Up!
Submit
Balance the following chemical equation (if necessary):
Rb(s) + RbNO3(s) → Rb2O(s) + N2(g)
3C,
2-
Reset
OS
< >
1
3
4
2.
5
07
6
7
8.
9
o
Answer:
im sorry but what is it post to be
Explanation:
Please help XD answer all of these questions to get 70 pnts!
Answer:
1 Density- degree of consistency measured by the quantity of mass per unit volume.
2 Cubic centimeters
3 Volume- Volume is the amount of space occupied by a substance, while mass is the amount of matter it contains. The amount of mass per unit of volume is a sample's density.
4 Liters
5 Mass- Scientific Definition of Mass Mass is the quantity of inertia (resistance to acceleration) possessed by an object or the proportion between force and acceleration referred to in Newton's Second Law of Motion (force equals mass times acceleration). In other words, the more mass an object has, the more force it takes to get it moving.
Explanation:
Answer:
What is density? The measure of how much matter is in a certain volume.
Which one of these are not a unit of volume? Answer: m² is not a unit of volume.
What is Volume? The length of an object.
Which of these is not a unit of mass? Metric ton (t)
What is mass?A measure of the amount of matter in an object or substance.
Calculate the number of Calories in a 5 fluid oz glass of red wine that contains 2.1 g carbohydrate and 13.8 g alcohol.
Answer:
ù
Explanation:
What are the 26 states of matter?
Bose–Einstein condensate.
Fermionic condensate.
Degenerate matter.
Quantum Hall.
Rydberg matter.
Rydberg polaron.
Strange matter.
Superfluid
In this case, the amount of calories is 105 calories.
One gram of alcohol provides approx. 7 calories, whereas one gram of carbohydrates contains 4 calories.In this case, the number of calories can be calculated by summing the calories provided by alcohol and carbohydrates.Number of calories = (2.1g x 4) + (13.8g x 7) = 8.4 + 96.6 = 105 calIn conclusion, the amount of calories, in this case, is 105 calories.
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