Answer:
amount of He = (7.91 × 10^22) ÷ (6.02 × 10^23) = 0.131mol (3sf)
Explanation:
you make use of the mole concept formula
amount(mol) = number of particles ÷ 6.02 × 10^23
(6.02 × 10^23 is the avogadro constant, which is an extremely important number in this formula for mole concept)
PLEASE HELP I added some food coloring to some water. The water changed color, but
It's still the same water that I can drink. This is an example of ??
A. Chemical Change
B. Physical Change
Answer:
its definitely a physical change as the way you see it now is different then before
Answer:
b
Explanation:
because it changed colors
What element is the least reactive: Si
or Ba?
Answer:
Noble gases are the least reactive of all known elements. That's because with eight valence electrons, their outer energy levels are full.
Elements: Argon
(60 points + brain list)
Which is the configuration of an atom in the ground state?
A)
2-8-2
B)
2-6-1
C)
2-7-2
D)
2-7-3
Answer:
Ground state means when n = 1
and here the electronic configuration is 2:8:2
Assume that a 100-base pair DNA double helix contains 45 cytosine bases. Use logical thinking to figure out how many adenine bases there will be. Explain how you know.
Answer:
You will not be allowed to have any learning aids while taking a test or ... A DNA molecule consists of three parts—a nitrogen base, ... There are four DNA nucleotides, each with one of the four nitrogen bases (adenine, thymine, cytosine, and guanine). The DNA forms a two-stranded spiral, or double helix.
Explanation:
hope this helps ✌️
Can someone help me on this letter E please
how many atoms are in 0.340 moles of sodium
The number of atoms that are in 0.340 moles of sodium is 2.047×10²³ atoms.
What is Avogadro's number?Avogadro's number is equal to 6.022×10²³ which gives idea about the number of atoms present in one mole of any substance.
i.e. In 1 mole = 6.022×10²³ atoms
Given moles of sodium = 0.34 mol
Number of atoms of sodium in given moles will be calculated as:
No. of Na atoms = 0.34mol × 6.022×10²³ atoms/mol = 2.047×10²³ atoms
Hence required number of atoms are 2.047×10²³ atoms.
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Of sulfuric acid, carbonic acid, nitric acid, and hydrochloric acid, which one is considered a weak acid
Answer:
nitric acid is considered as a weak acid
The strong acids are hydrochloric acid, nitric acid, sulfuric acid, hydrobromic acid, hydroiodic acid, perchloric acid, and chloric acid. The only weak acid formed by the reaction between hydrogen and a halogen is hydrofluoric acid
The Missouri River is a ______ of the Mississippi River.
Answer:
The missouri River is a Longesr tributary of the Mississippi River.
The Missouri River is tributary of the Mississippi River.
What is the Missouri River?The Missouri River is known as the longest river in the United States. Missouri flows east and south for 2,341 miles before mixing with the Mississippi River north of St Louis, Missouri.
The river drains include parts of ten U.S. states and two Canadian provinces although a tributary of the Mississippi, the Missouri River is marginally longer and has a comparable volume of water. When combined with the lower Mississippi River, it creates the world's fourth-longest river system.
People depend on the Missouri River and its tributaries as a source of transportation and sustenance. The Missouri River was the main route for the westward expansion of the U.S. during the 19th century.
During the 20th century, the Missouri River was developed for irrigation, flood control, and the generation of hydroelectric power. Fifteen dams formed the stem of the river, with hundreds more on tributaries.
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A crystal of quartz may be part of granite, sandstone, and the
metamorphic rock quartzite. Identify how that same crystal could be
found in all three rocks at different times.
HELP ME WITH THIS QUESTION
I have no idea what the answer is
ill guess c
Explanation:
g
If something is up higher it will have ________________ potential energy.
the same
more
less
Answer:
More
Explanation:
Someone help me answer this please! I’ll mark you brainliest
b. increase in surface area
Further explanationGiven
Speeding up a chemical reaction
Required
Factors used to speed up reactions
Solution
There are several factors that influence reaction kinetics :
1. Concentration
2. Surface area
3. Temperature
4. Catalyst
5. Pressure
6. Stirring
Temperature is related to the kinetic energy of the particles. Heat is absorbed causes the particles of matter to move faster so that the reaction can take place faster
The enlarged surface area of the reactants causes more particles to react with other particles.
50 g square block of sulfur can be broken into small pieces or powdered so that more particles come into contact with each other
How would you do this
The empirical formula = the molecular formula = C₁₀H₂₀O
Further explanationGiven
m = 0.15 g menthol
V = 0.0337 L
T = 150 +273 = 423 K
P = 100.2 kPa =0.99 atm
Required
molar mass
The molecular formula
Solution
Ideal gas law :
PV=nRT
n=PV/RT
n=0.99 x 0.0337/0.082 x 423
n=9.6 x 10⁻⁴
n = mass/Molar mass
Molar mass = mass/n
Molar mass = 0.15/9.6 x 10⁻⁴
Molar mass = 156.25 g/mol
The empirical formula of Menthol : C₁₀H₂₀O
(The empirical formula)n= molecular formula
(C₁₀H₂₀O)n=156.25
(12.011.10+1,007.20+15,999)n=156.25
(156.25)n=156.25
n=1
Is Mg(CH3COO)2 soluble or insoluble
Answer:
It is Soluble
Explanation:
Name- Magnesium acetate
It dissolves easily in water and alcohol.
how deficiency and excess of chromium
Answer:
The chromium found in foods will not hurt you. But taking excessive chromium supplements can lead to stomach problems and low blood sugar (hypoglycemia). Too much chromium from supplements can also damage the liver, kidneys, and nerves, and it may cause irregular heart rhythm.
what does newton’s first law of motion explain
Answer:
Newton's first law states that, if a body is at rest or moving at a constant speed in a straight line, it will remain at rest or keep moving in a straight line at constant speed unless it is acted upon by a force.
Where did you walk? what did you find most enjoyable while walking: listening to music, listening to an audio book, or nothing? how did your body react to this introductory amount of exercise? was it more exercise or less exercise than you are used to? if you did not walk, what other type of physical movement did you do?
Answer: walked from school few blocks before arriving .found charting and laughing with my pals most enjoyable while I was walking .my body reacted by tiredness, it is less exercise than I am capable of doing.
Explanation: did that help?
--What do you have to do to the coefficients of equation I below to get to equation II?
i) 2 [tex]SnO_{2}[/tex] + 4 [tex]H_{2}[/tex] --> 2 Sn + 4 [tex]H_{2} O[/tex]
ii) [tex]SnO_{2}[/tex] + 2 [tex]H_{2}[/tex] --> Sn + 2 [tex]H_{2} O[/tex]
--Can you divide equation II by another factor and still have it be correct? Why or why not?
--In a complete sentence, write down a method you could use to determine if an equation is written in the correct way.
Answer:
1
Explanation:
Answer:
divide all coefficients by 2.
Explanation:
The general area of the atom (outside the nucleus) where the e- are located is the — and —
What is the answer for number 2?
Answer:
It has mass but no charge.
Explanation:
The question asks to describe ONE of the subatomic particles that could be found at location X in the model, so you should think of protons and neutrons. Now all of the answers do NOT describe a proton, but the first answer describes a neutron. Neutrons have mass but no charge. Why? The neutron has two down quarks and one up quark, down quarks, have a charge of -1/3, and up quarks have a charge of +2/3. Doing the math, you'd see that (-1/3)2+2/3 is equal to a neutral charge. So a neutron WILL have a mass, but will NOT have a charge, as they are used to hold the nucleus together.
Answer:
the last one
Explanation:
How many grams of MgO are in 3.500 moles?
Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, lead has the highest mass. 141.05gram of MgO are in 3.500 moles.
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity or amount of substance. We know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number. 141.05gram is the mass of MgO.
Mathematically, the molar mass, mole and given mass can be related as
Mole of MgO =given mass of MgO ÷ molar mass of MgO
Molar mass of MgO= 40.30 g/mol
Mole of MgO= 3.500 moles
substituting the values, we get
3.500 moles = mass of MgO÷ 40.30 g/mol
Mass of MgO=141.05gram
Therefore, 141.05gram of MgO are in 3.500 moles.
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Which statement compares the attractive forces that hold particles together?
A. Polar covalent bonds and Van der Waals forces are weakly
attractive; ionic and hydrogen bonds are strongly attractive.
B. lonic and hydrogen bonds are weakly attractive; polar covalent
bonds and Van der Waals forces are strongly attractive.
C. lonic and polar covalent bonds are weakly attractive; hydrogen
bonding and Van der Waals forces are strongly attractive.
D. Hydrogen bonding and Van der Waals forces are weakly attractive;
ionic and polar covalent bonds are strongly attractive.
Polar covalent bonds and Van der Waals forces are weakly
attractive; ionic and hydrogen bonds are strongly attractive.
What is the attractive forces that hold particles together?We usually ranked the attractive forces that hold particles together while discussing them. Ionic bonds are the strongest, followed by hydrogen bonds that are somewhat weaker than that, and finally, his disciple disciple forces that are slightly weaker still. Then, Vander Wal's forces, also known as dispersion forces, are the weakest. The first one is ionic compounds, whereas the remaining three are frequently related to molecules or covalin compounds. Consequently, when comparing these attractive forces, the most accurate statement is is one of the first polar covalin bonds to form, resulting in dipole dipole forces. Let's call them polar covalin bonds, then. Van der Waals forces and polar covalin bonds are appealing on a weekly basis; these are the weakest.To learn more about attractive forces refer to:
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Answer:
D. Hydrogen bonding and Van der Waals forces are weakly attractive;
ionic and polar covalent bonds are strongly attractive.
Explanation:
.....
....
......
2.1 x 10^-3 x 2 x 10^2 =
a)
4.2 x 10^-5
b)
4.2 x 10^-1
c)
4.2 x 10^1
d)
4.2 x 10^-6
Answer:
I believe it is B
Explanation:
hope it helps. please let me know if it's wrong
Explain in a short sentence how you can tell if a reaction is a combustion reaction.
The reactants react with oxygen and there is energy formed.
Democritius thought that
are the smallest particles of matter.
Please give 1 answer.
A.
Electrons
B.
Protons
C.
Neutrons
D.
Atoms
(60 points + brain list) The correct electron configuration of the O2-ion is
A)
2-4
B)
2-5
C)
2-7
D)
2-8
Given the following reaction, how many liters of H2 gas are needed to form 35.5 grams of NH3?
N2 + 3H2 -> 2NH3
Answer:
170.4L
Explanation:
The reaction equation is given as:
N₂ + 3H₂ → 2NH₃
Mass of NH₃ = 35.5g
Problem:
How many liters of H₂ are needed to produce 35.5g of NH₃
Solution:
To solve this problem, let us find the number of moles of NH₃;
Number of moles = [tex]\frac{mass}{molar mass}[/tex]
Molar mass of NH₃ = 14 + 3(1) = 17g/mol
So;
Number of moles = [tex]\frac{35.5}{17}[/tex] = 5.07mole
From the balanced reaction equation:
2 mole of NH₃ will be produced from 3 mole of H₂
5.07mole of NH₃ will produce [tex]\frac{5.07 x 3}{2}[/tex] = 7.61mole of H₂
At STP;
1 mole of gas will occupy 22.4L
7.61 mole of H₂ will occupy 7.61 x 22.4 = 170.4L
What is a part's structure related to?
what is chemistry?
in your own word please 2-3 sentence
Answer:
the science that deals with the properties, composition, and structure of substances they undergo, and the energy that is released or absorbed during these processes.
Explanation:
Answer:
Is the scientific branch that deals with the composition and decomposition of elements and compounds in nature
Solve and use correct sig figs AND units: (Example of how to type: 3.26 m2)
The density of mercury is 13.6 g/mL. What is the mass of 3,426 mL of mercury?
Answer:
m = 46593.6 g
Explanation:
Given data:
Mass of mercury = ?
Volume of mercury = 3426 mL
Density of mercury = 13.6 g/mL
Solution:
Formula:
d = m/v
d = density
m = mass
v = volume
by putting values,
13.6 g/mL = m/ 3426 mL
m = 13.6 g/mL × 3426 mL
m = 46593.6 g
