Answer:
4.65 moles
Explanation:
1 mole ---> 6.022×10²³ atoms of si
X mole ---> 2.8×10²⁴ atoms of si
X= 2.8×10×10²³/6.022×10²³
=28/6.022
=4.65moles
What happens when an unstable nucleus undergoes radioactive decay?
A. Electrons change energy levels to balance the nucleus.
B. Energy is absorbed by the nucleus to make it more stable.
O C. Particles or electromagnetic radiation are emitted.
D. The nucleus increases in mass through radioactive decay.
how could an environmentally sustainable biofuel production be ensured in biofuel
production
Answer:
Explanation:
4.6 How could an environmentally sustainable biofuel production be ensured? ... Perennial feedstock crops, such as grasses or trees, can diversify production systems and help improve marginal or degraded land. Domestic government policy must become better informed of the international consequences of biofuel development.
1. In 1996 a meteor crashed into the Earth near Steelsville, Ontario. The resulting meteorite was found to contain 5,790 g of Molybdenum Chloride having a formula of Mo2Cl9. How many molecules of Mo2Cl9 are present in the 5,790 g meteor?
Answer:
6.38×10²¹ molecules
Explanation:
Formula for molybdenum chloride is:
Mo₂Cl₁₀
Molar mass is : (Molar mass for Mo) . 2 + (Molar mass for Cl) . 10
95.94 . 2 + 35.45 . 10 = 546.38 g/mol
We determine moles that are contained in 5.790 g of Mo₂Cl₁₀
5.790 g . 1 mol /546.38 g = 0.0106 moles
We count the molecules: 0.0106 mol . 6.02×10²³ molecules / mol =
6.38×10²¹ molecules
Remember that 6.02×10²³ is also called Avogadro's number (NA) which is the number of particles of anything, that are contained in 1 mol.
WHAT IS EXOTHERMIC EXPLAIN
please ।
।।।
Answer:
Exothermic reactions are reactions or processes that release energy, usually in the form of heat or light. In an exothermic reaction, energy is released because the total energy of the products is less than the total energy of the reactants.Explanation:
I hope this helps u have a nice day ☘Answer:
An EXOTHERMIC reaction is when energy is released.
Determine when to put on disposable gloves for work in the lab. Select one: After cleaning all the glassware for the experiment Before entering the laboratory room After setting up all the glassware but before handling chemicals Before handling any glassware or chemicals for the experiment
Answer: Disposable gloves should be put on before handling any glassware or chemicals for the experiment for work in the lab.
Explanation:
Disposable gloves are helpful in protecting skin of a person from coming in direct contact with chemicals.
As a result, it is important to wear disposable gloves before handling any glassware or chemicals for carrying out an experiment.
Thus, we can conclude that disposable gloves should be put on before handling any glassware or chemicals for the experiment for work in the lab.
What is the pH of a solution?
O A. A measure of the strength of the acid
B. A measure of the buffering ability of the solution
O c. A measure of the hydrogen gas concentration
O D. A measure of the acidity of the solution
Answer:
D. A measure of the acidity of the solution
Explanation:
pH is a measure of how acidic or basic a solution is, and is measured on a scale from 0-14, where 7 is neutral, anything less than 7 is acidic, and anything more than 7 is basic.
Use mathematics to prove that the 5.50 grams of salicylic acid (C7H6O3) used in this experiment is equal to 0.04 mol.
Answer:
Please find the answer to the question below
Explanation:
In chemistry, the following mathematical formula is used to calculate the number of moles contained by a substance:
mole = mass of substance (g)/molar mass of substance (g/mol)
Molar mass of salicylic acid (C7H6O3) = 12(7) + 1(6) + 16(3)
= 84 + 6 + 48
= 138g/mol
Mass = 5.50grams
mole = 5.5/138
mole = 0.039
Approximately, the number of moles of 5.5grams of salicylic acid is 0.04moles. This is in accordance with the mole value (0.04) given in this question.
What is the delta H when 72.0 grams H2O condenses at 100.00C?
Here are some constants that you MAY need.
specific heats heat of fusion heat of vaporization
H2O(s) = 2.1 J/g0C 6.01 kJ/mole 40.7 kJ/mole
H2O(L) = 4.18 J/g0C
H2O(g) = 1.7 J/g0C
2930 kJ
163 kJ
-163 kJ
-2930 kJ
Answer: The value of [tex]\Delta H[/tex] is -163 kJZ
Explanation:
The number of moles is defined as the ratio of the mass of a substance to its molar mass. The equation used is:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex] ......(1)
We are given:
Given mass of water = 72.0 g
Molar mass of water = 18 g/mol
Putting values in equation 1, we get:
[tex]\text{Moles of water}=\frac{72.0g}{18g/mol}\\\\\text{Moles of water}=4mol[/tex]
Calculating the heat released for the condensation process:
[tex]\Delta H=n\times \Delta H_{(vap)}[/tex] ......(2)
where,
[tex]\Delta H[/tex] = amount of heat released
n = number of moles of water = 4 moles
[tex]\Delta H_{(vap)}[/tex] = specific heat of vaporization = -40.7 kJ/mol
Negative sign represents the amount of heat released.
Putting values in equation 2:
[tex]\Delta H=4mol\times (-40.7kJ/mol)=-163kJ[/tex]
Hence, the value of [tex]\Delta H[/tex] is -163 kJ
Which of the following best describes a pair of elements that will form an ionic bond
Answer:
One of the elements must be a metal and another be a non metal.
One of the elements must lose electrons and the other must gain electrons.
A + 2 B + 4 C → products is known to be second order in A, first order in B and independent of the concentration of C. What is the value of the rate constant for this reaction if its rate is 0.783 M · s−1 when [A] = 5.00 M, [B] = 7.00 M, and [C] = 3.00 M? −2 −1 Answerinunitsof M ·s .
Answer:
4.47 × 10⁻³ M⁻² s⁻¹
Explanation:
Let's consider the following generic equation.
A + 2 B + 4 C → products
This reaction is known to be second order in A, first order in B and independent of the concentration of C (zero order in C). The rate law is:
rate = k × [A]² × [B] × [C]⁰
rate = k × [A]² × [B]
where k is the rate constant
When the rate is 0.783 M/s, [A] = 5.00 M, [B] = 7.00 M, and [C] = 3.00 M, the rate constant is:
k = rate / [A]² × [B]
k = 0.783 M/s / (5.00)² × (7.00) = 4.47 × 10⁻³ M⁻² s⁻¹
Tenisha solved the equation below by graphing a system of equations. help!!!!!
Answer:
(1.0, 1.4)
Explanation:
Graph the two equations [tex]\log_3 5x[/tex] and [tex]\log_5 (2x+8)[/tex]. The point of intersection is the solution to the system of equations.
Graph on Desmos:
[tex]\log_3 5x\implies \text{Red},\\\log_5 (2x+8)\implies \text{Blue}[/tex]
an engineer chooses to use bamboo as a building material because it grows quickly and needs little space to grow. This is an example of?
Answer:
A) This is an example of Green Design
Explanation:
If 15.0 mL of phosphoric acid completely neutralizes 38.5 mL of 0.150 mol/L calcium hydroxide, what is the concentration of the phosphoric acid?
Answer:
Let me give it a try.
H3PO4 + Ca(OH)2 = Ca3(PO4)2 + H2O
Balancing this reaction
2H3PO4 + 3Ca(OH)2 == Ca3(PO4)2 + 6H2O.
Moles= Molarity x Volume
Volume = 38.5ml = 0.0385L
Moles of Ca hydroxide = 0.150m/L x 0.0385L
(Notice the units canceling out...leaving moles).
=0.005775moles of Ca(OH)2.
From balanced reaction...
3moles of Ca(OH)2 completely reacts with 2moles of H3PO4
0.005775moles of Ca(OH)2 would completely react with....
= 0.005775 x 2/(3)
=0.00385moles of H3PO4.
Now we're looking for its Concentration in Mol/L
Molarity=Moles of solute/Volume of solution(in L)
Volume of solution assuming no other additions to the reaction = 15ml + 38.5ml =53.5ml =0.0535L
Molarity = 0.00385/0.0535
=0.072Mol/L.
If this is wrong
then Simply Try The formula for Mixing of solutions
C1V1 = C2V2
0.15 x 38.5 = C2 x (15+38.5)
C2 = 0.11M/L.
When your body is warmed by the sun during the winter, this process is said to be
a. exothermic.
b. endothermic.
c. isothermic.
d. none of the above
Answer:
B. Endothermic
Explanation:
Your body is absorbing the heat.
Find the surface area of a square pyramid with side length 5 cm and slant height 4 cm.
Answer:
h = height
s = slant height
a = side length
P = perimeter of base
e = lateral edge length
r = a/2
V = volume
L = lateral surface area
B = base surface area
A = total surface area
Explanation:
Volume of a square pyramid:
V = (1/3)a2h
Slant Height of a square pyramid:
By the pythagorean theorem we know that
s2 = r2 + h2
since r = a/2
s2 = (1/4)a2 + h2, and
s = √(h2 + (1/4)a2)
This is also the height of a triangle side
Lateral Surface Area of a square pyramid (4 isosceles triangles):
For the isosceles triangle Area = (1/2)Base x Height. Our base is side length a and for this calculation our height for the triangle is slant height s. With 4 sides we need to multiply by 4.
L = 4 x (1/2)as = 2as = 2a√(h2 + (1/4)a2)
Squaring the 2 to get it back inside the radical,
L = a√(a2 + 4h2)
Base Surface Area of a square pyramid (square):
B = a2
Total Surface Area of a square pyramid:
A = L + B = a2 + a√(a2 + 4h2))
A = a(a + √(a2 + 4h2))
Please help I’ll give brainliest
Answer:
N2, O2 and Br2
Explanation:
N2, O2 and Br2 are formed of two atoms, so they are diatomic
This is a list of the seven diatomic elements. The seven diatomic elements are:
Hydrogen (H2)
Nitrogen (N2)
Oxygen (O2)
Fluorine (F2)
Chlorine (Cl2)
Iodine (I2)
Bromine (Br2)
What does a vacuole mean
Answer:
a space or vesicle within the cytoplasm of a cell, enclosed by a membrane and typically containing fluid.
or
a small cavity or space in tissue, especially in nervous tissue as the result of disease.
Which of the following statements is true?
a. ΔHfus = ΔHsolid
b. ΔHfus = –ΔHsolid
c. Hfus is always negative.
d. ΔHsolid is always positive.
Answer:
c. Hfus is always negative.
Explanation:
Because energy is released when fusing solids
A. 2 pts: In terms of conservation of mass, what were the results of each experiment (which one conserved mass and which one did not)?
B. 4 pts: PROVIDE a SPECIFIC explanation for "why" the results in both videos were different.
. 2 pts: Discuss differences in the experimental steps between the two videos (for example what was done in video one that was not done in
video two, why would this make a difference in conserving mass?)
• 2 pts: Look at both chemical equations (below for convenience), what difference in the type of products would have contributed to the
differences in why one conserved mass and one did not?
REACTION 1: Pb(NO3)2 (aq) + 2K1 (aq) --> 2KNO3 (aq) +Pölz (s)
• REACTION 2: NaHCO3(s) + CH3COOH(aq) → CO2(g) + H2Om + CH3COONa(aq)
Answer:
dftdffdgxrdfdrdxxxxdddddddddddddeeertdffddy
Joelle is a manager at a construction company, and she is interested in the chemistry behind the materials they use. She has begun studying the materials used to fill walls. She knows that to keep the temperature inside a room steady the material must be a thermal insulator, and she predicts that materials should not be acidic or else they would dissolve too easily in water.
Which of these is a molecular ingredient that could be used in a wall-filling material ?
C27H36N2O10
Na6Ba6
NeNa
HCl
Answer:
a
Explanation:
A molecular ingredient that could be used in a wall-filling material is C₂₇H₃₆N₂O₁₀, is not a good thermal insulator, hence option A is correct.
The big molecule C₂₇H₃₆N₂O₁₀ is a poor thermal insulator. Since NeNa is a relatively reactive chemical, it would probably dissolve in water far too quickly. The acidic molecule HCl would dissolve far too quickly in water.
Not a good thermal insulator is C₂₇H₃₆N₂O₁₀. It is a big molecule composed of a lot of hydrogen atoms. Since hydrogen atoms are excellent heat conductors, they would be ineffective in stopping heat from passing through a material used to fill a wall.
Thus, the option (A) C₂₇H₃₆N₂O₁₀ is correct.
Learn more about thermal insulator, here:
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if five elements have atomic numbers 2,3,6,9 which two numbers are the most reactive??
Explanation:
[tex]element \: with \: 2 \: atomic \: number \\ \\ is \: stable \: because \: it \: has \: already \: \\ \\ completed \: its \: orbit \: \\ \\ but \: atomic \: number \: with \: 3 \: and \: 9 \\ \\ will \: have \: to \: become \: stable \: \\ \\ after \: giving \: one \: electron \\ \\ so \: \: element \: with \: 3 \: and \: 9 \: atomic \: number \\ \\ is \: most \: reactive[/tex]
How is the height of grasses in grasslands related to precipitation?
Short and tall grasses prefer very low amounts of precipitation
o Shorter grasses grow in areas that receive more precipitation
o Taller grasses grow in areas that receive more precipitation
o Short and tall grasses prefer the high amounts of precipitation
Answer:
It just does
Explanation:
Answer:
Tallgrass Praries have more Rainfall
Explanation:
Which of the following is the balanced chemical equation that represents the chemical reaction of hydrogen and oxygen to produce water
Answer:
The following equation describes the burning of hydrogen gas to form liquid water. 2H2(g) + O2(g) → 2H2O(l ) Chemical equations give the following information about chemical reactions.
Explanation:
Which sequence of steps describes the life cycle of a lake?
A. Runoff fills a depression - sediments build up - water becomes
increasingly shallow
B. Runoff fills a depression - sediments are eroded - water becomes deeper
C. Runoff fills a depression - sediments build up
- water rises continuously
D. Runoff fills a depression - sediments are eroded - water spreads over a wider area
Answer:
The actual sequence of steps which describe the life cycle of a lake is given below:
C. Runoff fills a depression - sediments build up
- water rises continuously
Explanation:
This is because, the water which builds up as a result of the runoff water accumulating on the depression helps towards building up. When it must have accumulated greatly, it ends up forming a lake.
Given the structural formula: This compound is classified as an
Answer:
A.) aldehyde is the answer
From the given structural formula, the compound is ethanamide and thus, belongs to the group of amides. Thus, the correct option is B.
Amide is a functional group of organic compounds having an acyl group (R-C=O) linked to amine group (-NR¹R² where R¹ and R² are hydrogen atoms or alkyl groups). The amide functional group is given as -CON= (not double bond with N, but two distinct single bonds).
Amides can be classified into the following types depending on the moiety attached to nitrogen other than the carbonyl carbon:
1. Primary amides - amide in which the nitrogen atoms is attached to two hydrogen atoms
2. Secondary amides - in which the nitrogen atom is attached to one hydrogen and one alkyl group.
3. Tertiary amides - in which the nitrogen atom is attached to two alkyl groups.
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Please help, only a couple of days left!!!
Answer:
the heat from the universe during the big bang
a.k.a.
ITS A
Explanation:
the universe is still expanding, so what is gonna be used to create that new matter that's expanding the universe? energy and heat from the beginning of the universe! the universe started off as this point that was probably smaller than a quantum foam and infinite heat and started expanding from there
Explain why solids and liquids are difficult to compress
whereas gases can easily be compressed.
Answer:
Because they take up a certain amount of volume because there is no space in-between the particles, a gases can be compressed because there is alot of space in-between each particle
Explanation:
Which question would most likely be studied by a biologist?
A.
How can a drug that treats cancer be synthesized?
B.
How can cancer-causing substances be regulated?
C.
How much ultraviolet radiation passes through the atmosphere?
D.
What causes cancer cells to grow uncontrollably?
Answer:
The correct answer would be - D. What causes cancer cells to grow uncontrollably?
Explanation:
A Biologist is a person that studies living organisms and the study of living organisms and their process called biology. Biology is a very vast field that involves many branches such as zoology, botany, biochemistry, immunology, biophysics, anatomy, ecology and many more.
So, given all are can be an example of the study biology wanted to do, however, the question most likely studied by a biologist would be What causes cancer cells to grow uncontrollably as it deals with an organism and their biological process.
Which of the following statements is correct about electrical insulators?
A. They do not contain any atoms.
B. Their protons are not allowed to move about freely.
C. The electrons are not able to move about freely.
D. They are good at conducting heat only.
Answer:
the answer is C in my opinion.. hope this might be helpful
An example of a product made from a synthetic material is
Question 5 options:
A)
a PET plastic water bottle.
B)
knitted wool socks.
C)
a cotton t-shirt.
D)
a pine 2×4 board.
Hi there! A simple answer and explanation is below :)
Answer:
A) PET plastic water bottle
Explanation:
Plastic goes through a manufacturing process before being used to make bottles for liquids like milk, soda, motor oil, and shampoo, as well as dry items like pharmaceuticals and nutritional supplements. Plastic is made up of a variety of organic polymers, including polyethylene and ethylene, in its unprocessed condition. In a soft state, plastic can be molded into the desired shape and then cast into a solid stat
