Answer:
Avogadro’s Number
Avogadro’s NumberIt certainly is easy to count bananas or to count elephants (as long as you stay out of their way). However, you would be counting grains of sugar from your sugar canister for a long, long time. Atoms and molecules are extremely small – far, far smaller than grains of sugar. Counting atoms or molecules is not only unwise, it is absolutely impossible. One drop of water contains about 10 22 molecules of water. If you counted 10 molecules every second for 50 years without stopping you would have counted only 1.6 × 10 10 molecules. Put another way, at that counting rate, it would take you over 30 trillion years to count the water molecules in one tiny drop.
Avogadro’s NumberIt certainly is easy to count bananas or to count elephants (as long as you stay out of their way). However, you would be counting grains of sugar from your sugar canister for a long, long time. Atoms and molecules are extremely small – far, far smaller than grains of sugar. Counting atoms or molecules is not only unwise, it is absolutely impossible. One drop of water contains about 10 22 molecules of water. If you counted 10 molecules every second for 50 years without stopping you would have counted only 1.6 × 10 10 molecules. Put another way, at that counting rate, it would take you over 30 trillion years to count the water molecules in one tiny drop.Chemists needed a name that can stand for a very large number of items. Amedeo Avogadro (1776 – 1856), an Italian scientist, provided just such a number. He is responsible for the counting unit of measure called the mole. A mole (mol) is the amount of a substance that contains 6.02 × 10 23 representative particles of that substance. The mole is the SI unit for amount of a substance. Just like the dozen and the gross, it is a name that stands for a number. There are therefore 6.02 × 10 23 water molecules in a mole of water molecules. There also would be 6.02 × 10 23 bananas in a mole of bananas, if such a huge number of bananas ever existed
Answer:
Mass = 2000 g
Explanation:
Given data:
Number of molecules of hydrogen = 6.023×10²⁶
Mass of hydrogen = ?
Solution:
1 mole of hydrogen contain 6.022×10²³ molecules
6.023×10²⁶ molecules× 1 mol/ 6.022×10²³ molecules
1.00 ×10³ mol
1000 mol
Mass of hydrogen:
Mass = number of moles × molar mass
Mass = 1000 mol × 2 g/mol
Mass = 2000 g
Use the data from the following figures to answer the questions below.
SUBSTANCE
DENSITY_9
cm
cork
0.22
water
1.0
sugar
1.6
aluminum
2.7
79
gold
19.3
02000 Ossewwe, in
The cube has a mass of 72.9 g.
iron
3 cm
3 cm
3 cm
2008 Ogsewu, in
What is its density in g/cm?
What substance is it?
Answer:
2.7g/cm³
Aluminum
Explanation:
Given parameters:
Mass of the cube = 72.9g
Unknown:
Density of the cube = ?
Solution:
To solve this problem, we need to find the density of the cube. The mass is given and the dimensions of the solid figure.
Now;
Density is the mass per unit volume of a substance
Density = [tex]\frac{mass}{volume}[/tex]
Volume of the cube = L³ = 3³ = 27cm³
So;
Density = [tex]\frac{72.9}{27}[/tex] = 2.7g/cm³
The body is aluminum because it has a density of 2.7g/cm³
A patient provides a urine sample. The density of the patient's urine is 1.0192 g/mL. What is the specific gravity of the urine?
Answer:
1.092
Explanation:
Density = 1.0192 g/mL
oecific gravity = ?
Specific gravity is the ratio of a material's density with that of water.
The density of water at 4 degrees Celsius = 1 g/mL
Specific gravity = 1.0192 / 1 = 1.0192
Because specific gravity is a ratio, it has no dimension.
When 10 Joules of heat are transferred into 30 g of Copper at 18.20oC, the final temperature is 19.07oC. What is the specific heat of copper?
Answer:
c = 0.38 j/g.°C
Explanation:
Given data:
Heat absorbed by copper = 10 j
Mass of copper = 30 g
Initial temperature = 18.20°C
Final temperature = 19.07°C
Specific heat capacity of copper = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 19.07°C -18.20°C
ΔT = 0.87 °C
10 J = 30 g×c×0.87 °C
10 J = 26.1 g.°C×c
c = 10 J /26.1 g.°C
c = 0.38 j/g.°C
What is the mass of insoluble lead(II) iodide (461.0 g/mol) produced from 0.830 g of potassium iodide (166.00 g/mol) and aqueous lead(II) nitrate?A) 4.61 g. B) 0.149 g.C) 2.31 g.D) 1.15 g.E) 0.598 g.
Answer:
C
Explanation:
The mass of insoluble lead iodide produced from 0.830 g of potassium iodide in a reaction with lead nitrate is 2.31 g. Thus option C is correct.
What is lead iodide?Lead iodide or PbI is an ionic compound formed from the ionic bonding between metal lead and iodine. It is industrially prepared from the reaction of aqueous lead nitrate with potassium iodide.
Potassium iodide easily reacts with lead iodide as per the reaction written below:
[tex]\rm KI + PbNO_{3} \rightarrow KNO_{3} + PbI[/tex]
As per this reaction one mole of potassium iodide produce one mole of lead iodide. The molar mass of potassium iodide is 166 g/mol and that of lead iodide is 461 g/mol.
Thus, 166 g of potassium iodide gives 461 g of lead iodide. The mass of lead iodide then produced from 0.830 g of potassium iodide is calculated as follows:
mass = (0.830 g × 461)/ 166
= 2.31 g.
Hence, the mass of insoluble lead iodide produced from 0.830 g of potassium iodide in a reaction with lead nitrate is 2.31 g and option C is correct.
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The equation 2NaNO3 + CaCl2 - 2NaCl + Ca(NO3)2 is balanced. How many atoms of sodium (Na) are there on either side of the equation? one two four six
Answer:
fou maybe
Explanation:
it was my answer hehe
Answer:2
Explanation:
Because it is
When metals, non metals,and metallics are composed according to luster, which is best description of the appearance of metalloids
Answer:
Metalloids are metallic-looking brittle solids that are either semiconductors or exist in semiconducting forms, and have amphoteric or weakly acidic oxides. Typical nonmetals have a dull, coloured or colourless appearance; are brittle when solid; are poor conductors of heat and electricity; and have acidic oxides.
Explanation:
Metalloids are sometimes known as semimetals. Metalloids are yellow elements on the periodic table that often lie along the stair-step line.
What are Semimetals ?Metals are at the bottom left of the periodic table, and non-metals are at the top right.
Semimetals are found at the diagonal dividing line between metals and non-metals.
If there is barely any overlap between the top and bottom of the valence band, a substance is classified as a semimetal.
According to the electronic band theory, solids can be classified as metals, semimetals, insulators, or semiconductors.
An element that resembles metal in some ways but is not a metal For instance, although arsenic is a metalloid and appears to be a metal, it really conducts electricity poorly.
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Provide an example of a Food Chain.
Answer: Diamond is the name ^-^
A food chain only follows just one path as animals find food. eg: A hawk eats a snake, which has eaten a frog, which has eaten a grasshopper, which has eaten grass. A food web shows the many different paths plants and animals are connected. eg: A hawk might also eat a mouse, a squirrel, a frog or some other animal.
Hope this helps ^_^
Use what you’ve learned about Lewis structures and formal charges to predict which of the following sulfur-containing molecule(s) would be least likely to exist.
SO2
H2S2
SCl2
HS
HSOH
Answer:
its DDDDDDDDDDDDDDDDDD
The structure that is least likely to exist is HS.
Sulfur is an element in group 16. Sulfur is a divalent element that has two lone pairs of electrons. This means that sulfur forms compounds in which it is bonded to two atoms or groups.
All the molecules listed can exist because they consists of structures in which sulfur is bonded to two atoms or groups. The only structure that can not exist is HS because it does not satisfy the valency of sulfur.
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Give examples of solid materials that dissolve completely in liquid materials.How about those that do not?
ANSWER: Things like salt, sugar and coffee dissolve in water. They are soluble. They usually dissolve faster and better in warm or hot water.
The substrate is the same in parts a and b, however the mechanism that proceeds is different. Explain how the choice of solvent (acetone vs. methanol) influences the reaction mechanism between benzyl bromide and a nucleophile.
Answer:
See explanation
Explanation:
The reaction of a benzyl bromide with a nucleophile may proceed by SN1 or SN2 mechanism depending on the nature of the solvent used.
Since SN1 reaction involves the formation of a carbocation, it usually predominates in the presence of a poor nucleophiles and protic solvents. Hence when methanol is used as solvent and a poor nucleophile is used, SN1 mechanism predominates.
However, when acetone which is an aprotic solvent is used in the presence of a good nucleophile, SN2 reaction mechanism predominates.
A Rolaids tablet contains calcium for neutralizing stomach acid. if a Rolaids tablet neutralizes 24.65ml of 0.547m hydrochloric acid, how many milligrams of calcium carbonate are in a Rolaids tablet?
There are 674 mg of calcium carbonate in a Rolaids tablet
Further explanationReaction
CaCO₃ + 2HCl ⇒ CaCl₂ + CO₂ +H₂O
V HCl = 24.65 ml
M HCl = 0.547
mol HCl :
[tex]\tt 24.65\times 0.547=13.48~mlmol[/tex]
ratio mol CaCO₃ : HCl = 1 : 2, so mol CaCO₃ :
[tex]\tt \dfrac{1}{2}\times 13.48=6.74~mlmol=6.74\times 10^{-3}~mol[/tex]
mass of CaCO₃ (MW=100~g/mol) :
[tex]\tt 6.74\times 10^{-3}\times 100=0.674~g=674~mg[/tex]
What is the answer? Please
Answer:
Cell
Explanation:
I just passed this unit a month ago.
Answer:
It is 6. Cell
Explanation:
Cells make up the smallest level of a living organism such as yourself and other living things. The cellular level of an organism is where the metabolic processes occur that keep the organism alive. That is why the cell is called the fundamental unit of life.
I really hope this helped. God bless you and have a great day! :-)
2. A person with a body temperature of 37°C holds an ice cube with a temperature of 0°C
in a room where the air temperature is 20°C. The direction of heat flow is
a) From the person to the ice, only
b) From the person to the ice and air, and from the air to the ice
c) From the ice to the person, only
d) From the ice to the person and air, and from the air to the person
Answer:
b) From the person to the ice, and from the air to the ice
Explanation:
The direction of heat flow in the room is from the person to the ice and from the air to the ice.
The ice is at the lowest temperature.
Heat flows from a place with a higher measure of heat to a place with a lower amount of heat. Since the ice has the lowest heat, there is a thermal gradient set up. Heat will flow from the body and air towards to the ice.Sweat is made up of all EXCEPT what?
*
A.Sugar
B.Salt
C.Urea
D.Urine
Consider two solutions separated by a semipermeable membrane, as shown in the illustration to the right. The membrane allows the passage of small molecules and ions, but not large molecules like polysaccharides or proteins. Solution A contains a 10% solution composed
of glucose and the protein albumin dissolved in water.
Solution B contains a 5% solution of NaCl in water. Indicate whether each substance in the system would flow into Solution A, Solution B, or neither.
1. Water
2. NaCl
3. glucose
4. Albumin
5. Glucose
Answer:
The correct movement would be -
1. Water - into solution A.
2. NaCl - into solution A.
3. glucose - into Solution B.
4. Albumin - neither.
Explanation:
All the substances are separated by the semipermeable membrane and the semipermeable membrane allows the only small molecule to pass through it. So the movement of the given substance would be -
1. Water - into solution A.
Water molecules are small and can easily pass through the semipermeable membrane as it is given that the solution b has low solute concentration and solution A has high solute concentration. It is known that the movement of the solvent always takes place from low solute concentration to high so the movement of water will be into solution A.
2. NaCl - into solution A.
The movement of small ionic molecule NaCl is always from high to low concentration as it is given that solution B has high concentration than solution A so movement will take place into solution A.
3. glucose - into Solution B.
It is also a small molecule and moves from the high glucose region to the low glucose concentration region, in solution A the concentration of glucose is high than solution B so movement would be into solution B.
4. Albumin - neither.
Albumin is a protein which is macromolecule and large in size to pass through the semipermeable membrane so, albumin move neither solution A nor solution B.
When the particles, such as atoms, molecules, or ions, of a solid phase are arranged in a regular pattern, then the solid is a(n) __________.
Answer:
Crystal / Crystalline Structure
Explanation:
These structures contain particles in a regular pattern, and we call them crystals.
Hope this helped!
A student uses the periodic table to construct a model that uses a simple diagonal arrow to depict decreasing electronegativity. Where should the arrow point to indicate the lowest electronegativity of all the elements?
Answer:
helium
Explanation:
helium has the highest ionization energy level
An element's ability to attract shared electron thus forming covalent bonds is a measure of it's electronegativity. Hence, in other indicate decreasing level of electronegativity, arrow must point to the left across groups and down along the column.
Electronegativity of elements on the periodic table decreases along the groups on the periodic table with elements, Helium and Fluorine being the most electronegative Along the columns, electronegativity decreases downwards with cesium and francium being the least electronegative.Therefore, the arrow should point from right to left across the group and top to bottom along the columns.
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If element X has 6 valence electrons, what is the formula between element X and
magnesium.
a. X6Mg2
b. MgX3
c. MgX
d. XMg
Calculate the mass of zinc that reacts with 16.23 g of hydrochloric acid to form 15.2 g of zinc chloride and 18.97 g of hydrogen gas
Answer:
17.94 g
Explanation:
Which of the following grouping contains only representative elements?
A. Na, Co, S
B. Ni, Ga, Zn
c. AI, Mg, LÍ
D. CI, O, Cd
Answer:
C
Explanation:
Al=Aluminum
Mg=Magnesium
A compound of copper and sulfur contains 76.84 g of metal and 38.53 g of nonmetal. How many grams of copper are in 3801 kg of the compound? How many grams of sulfur?
Answer:
There are:
2'531,500 g Cu1'269,500 g SExplanation:
First calculate the percentage of Cu and S in the compound:
Total mass = 76.84 g + 38.53 g = 115.37 g% metal (Cu) = 76.84/115.37 * 100% = 66.6%% metal (S) = 38.53/115.37 * 100% = 33.4%These percentages will remain the same no matter how much of the compound we analyze.
Now we calculate the grams of Cu and S in 3801 kg of the compound:
kg Cu = 3801 kg * 66.6/100 = 2531.5 kg Cug Cu = 2531.5 kg * 1000 = 2531500 g Cukg S = 3801 kg * 33.4/100 = 1269.5 kg Sg S = 1269.5 kg * 1000 = 1269500 g S
do seeds need energy to germinate
Answer:
Seeds need oxygen so that they can produce energy for germination and growth. The embryo gets energy by breaking down its food stores. Like all organisms, this is done through a process known as aerobic respiration. —a series of reactions where energy is released from glucose, using oxygen.
8
Which of the pictures demonstrates a state of matter WITHOUT a fixed shape or fixed
volume?
Answer:
K
Explanation:
The picture that demonstrates a state of matter without a fixed shape or fixed volume is picture K.
Gases are one of the three states of matter without a fixed shape and volume. They simply take up the shape of their containers and are free to move all about.
Liquids and solids are known to have fixed shape and volume. Liquids are know for their ability to flow. Figure LSolids are rigid bodies. It is the figure JWhat had the study of fossils allowed scientist to do
Answer:
it let them know what lived before them besides their old, dead grandpas
Explanation:
aaaaaaaa
Answer:
It let us know what came before us, what the past was like, and gave them a little idea of what happened.
Explanation:
if the frisbee represents light, what does the fence represent?
Answer:
I think vaccum
Explanation:
Answer:
It represents how light can go through something.
Explanation:
The chemical reaction between iron (Fe) and oxygen (O) results in the loss of electrons from iron. This reaction is an example of _____.
A) respiration
B) sublimation
C) oxidation
D) combustion
Answer:
d combustion because iron and oxegen need eachother
Answer:
The Correct answer would be Oxidation.
Explanation:
A soccer player practices kicking the ball into the goal from halfway down the soccer field, which is 45 meters away. The time it takes for the ball to get to the goal from the time it is kicked is 3 seconds. The player wants to know the velocity of the ball.
Is there enough information to calculate this?
Yes, displacement is 45 meters, elapsed time is three seconds, and the direction is toward the goal. Velocity is 135 m/s toward the goal.
No, only speed can be calculated from the distance of 45 meters and the time of 3 seconds.
Yes, displacement is 45 meters, time is three seconds, and the direction is toward the goal. Velocity is 15 m/s towards the goal.
Answer:
Yes, displacement is 45 meters, time is three seconds, and the direction is toward the goal. Velocity is 15 m/s towards the goal.
Explanation:
Hope this helped!
An airplane weighing 80,000. kg at takeoff reaches a speed of 880 km/h. What is the de Broglie wavelength in meters of the plane?
Answer:
3.39 * 10^-41 m
Explanation:
Given that:
speed of airplane = 880 km/hr
Mass of airplane = 80000 kg
Debroglie wavelength (λ) = h / mv
h = planck's constant = 6.626 * 10^-34
; mass = 80000kg
Velocity = 880km/hr to convert to m/s
Velocity = (880 * 1000m) / 3600 =244.44 m / s
λ = (6.626 * 10^-34) /(80000*244.44)
λ = (6.626 * 10^-34) / 19555200
λ = 3.3889 *10^-41
λ = 3.39 * 10^-41 m
A cube of iron and a cube of wood, each having a volume of V = 3.25 10-4 m3, are each placed in a large beaker of water. The density of the wood is rhowood = 3.73 102 kg/m3 and the density of the iron is rhoiron = 7.86 103 kg/m3. Calculate the buoyant force on each. (The cube of wood is allowed to float at the surface.)
Answer:
anor277
Nov 17, 2017
Well, by definition,
Molarity
≡
Moles of solute
Volume of solution
Explanation:
And thus...
moles of solute
=
molarity
×
volume
We use a molar quantity of
80.3
⋅
g
174.01
⋅
g
⋅
m
o
l
−
1
=
0.461
⋅
m
o
l
with respect to
potassium sulfate
And thus
volume
=
moles of solute
molarity
80.3
⋅
g
174.01
⋅
g
⋅
m
o
l
−
1
3.12
⋅
m
o
l
⋅
L
−
1
=
0.148
⋅
L
.
The buoyant force is one that acts against the weight of an object suspended in a fluid. The value of the buoyant force on each are:
i. Buoyant force on the cube of iron = 25.0 N
ii. Buoyant force on the cube of wood = 1.20 N
Upthrust is a force which acts against the direction of the weight of an object when suspended in a fluid. It acts majorly upwards against gravity, and it can be referred to as a buoyant force.
The amount of upthrust on object in a fluid sometimes depends on the density, volume and gravity acting on the object.
So that;
Upthrust = density x volume x gravity
Thus from the given question;
i. The buoyant force on the cube of iron can be determined by:
Upthrust = 7.86 x [tex]10^{3}[/tex] * 3.25 x [tex]10^{-4}[/tex] * 9.8
= 25.034
Upthrust = 25.0 N
Therefore, the buoyant force on the cube of iron is 25.0 N.
ii. The buoyant force on the cube of wood can be determined by:
Upthrust = 3.73 x [tex]10^{2}[/tex] * 3.25 x [tex]10^{-4}[/tex] * 9.8
= 1.1880
Upthrust = 1.20 N
Therefore, the buoyant force on the cube of wood is 1.20 N.
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How do animals get energy from food?
Answer:
because plants have energy in them from the sun and
Answer:
Animals get energy from food through the digestion process :)