Answer:
B. 138
Explanation:
Based on isotope notation:
[tex]^X_nA[/tex]
For the atom A, the mass number, X, is the sum of neutrons and protons and
n is the number of protons = Atomic number.
The number of protons depends of the nature of the atom. For example, Carbon has 12 protons, hydrogen 1 and Radium has 88 protons.
The radium-226 means the mass number is 226. Thus, number of neutrons are:
Mass number - Atomic number
226 - 88 = 138
Right answer is:
B. 138Answer:
Unit 4 Lesson 2:
Energy Release Quick Check
1. 138 neutrons
2. The conversion of an atom of one element into a different element through nuclear changes.
3. A nuclear equation is balanced according to mass number. A chemical equation is balanced according to the total mass before and after the change.
4. 82
5. Some of the matter is converted to energy.
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The strongest bases have pH values close to
Answer:
Explanyour mmation:
Which elements are diatomic?
1
H
3
Li
6
с
7
N
8
0
9
F
5
B
13
AI
2
He
10
Ne
18
Ar
15
P
16
S
17
CI
11
Na
19
K
4.
Be
12
Mg
20
Ca
38
Sr
31
Ga
33
As
35
Br
36
Kr
34
Se
52
Te
14
Si
32
Ge
50
Sn
82
Pb
114
FI
51
Sb
53
1
37
Rb
55
Cs
54
Xe
E
86
49
In
81
TI
113
Nh
56
Ba
83
Ві
84
Po
85
At
Rn
87
Fr
88
Ra
115
Mc
116
Lv
118
117
Ts
Og
Diatomic elements have to atoms of the element in a molecule.
What are diatomic elements?Diatomic elements are those elements whose atoms combine together to form molecules of the element. The elements that are diatomic in the list are;
HNOFClBrSeTeHence, diatomic elements have to atoms of the element in a molecule.
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A scientist completes a thermal decomposition reaction. 12.25g of calcium carbonate, CaCO3, is heated
and forms calcium oxide, Cao, and carbon dioxide, CO2.
a. Write a balanced chemical equation to demonstrate this reaction. Include state symbols.
b. Calculate the number of moles of calcium carbonate that is thermally decomposed in this
reaction.
Ok
Moles of calcium carbonate : 0.1225
Further explanationA reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
CaCO₃(s) → CaO(s) + CO₂(g)
mass of CaCO₃ : 12.25 g
mol CaCO₃(MW=100 g/mol) :
[tex]\tt mol=\dfrac{mass}{MW}\\\\mol=\dfrac{12.25}{100}\\\\mol=0.1225[/tex]
The answer to the problem: 3.6 x 4.639 + 5.831 = _____, written to the correct number of significant digits is:
Answer:
3.6 x 4.639 + 5.831 = 2000
Explanation:
In this problem, we need to find the value of 3.6 x 4.639 + 5.831.
Here, 3.6 has 2, 4.639 and 5.831 has 4 significant figures.
We can use BODMAS RULE to find it as follows :
3.6 x 4.639 + 5.831 = (3.6 x 4.639) + 5.831
= 2325.96 + 5.831
in significant gigure,
= 2300 + 5.831
= 2305.831
In one significant figure,
= 2000
Hence, the answer of the problem is 2000.
Help as soon as possible please tell why you chose A B C OR D
Answer: the answer is A
Explanation:
g cr2o3 molar mass compound containing chromium and silicon contains 73.52 mass percent chromium. Determine its empirical formula.
Adding ammonia (NH3) to water makes NH4. This will cause the pH of the solution to:______.
Answer:
pH increases
Explanation:
The ammonia, NH₃, reacts with water, H₂O, as follows:
NH₃ + H₂O → NH₄⁺ + OH⁻
That means when NH₃ is added to water, some OH⁻ is produced. As [H⁺] is inversely proportional to [OH⁻], the increase of OH⁻ causes the decrease og H⁺. And when H⁺ decreases,
pH increases
How many gram are in 4.5 moles of Li2O
Answer:
134.5 grams
Explanation:
There are 134.5 grams in 4.5 moles of Li2O (lithium oxide).
BRAINLIEST PLZZZZZ
Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 135g are in 4.5 moles of Li[tex]_2[/tex]O.
What is mole?The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity of amount of substance. we know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number. Mole is inversely proportional to molar mass of given substance. Mole is directly proportional to given number of atoms present in that substance.
Mathematically, molar mass and mole can be related as
mole of Li[tex]_2[/tex]O =given mass of Li[tex]_2[/tex]O÷ Molar mass of Li[tex]_2[/tex]O
Molar mass of Li[tex]_2[/tex]O=30 g/mol
mole of Li[tex]_2[/tex]O=4.5 moles
Substituting the values
4.5 moles =mass of Li[tex]_2[/tex]O÷ 30 g/mol
mass of Li[tex]_2[/tex]O = 135g
Therefore, 135g are in 4.5 moles of Li[tex]_2[/tex]O.
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While exploring an ancient lava field, a geologist discovers a piece of granite that has a coating of soft, crumbling rust. What is the most likely explanation for this rust?
A.
Exposure to air has caused the iron-bearing minerals in the granite to oxidize.
B.
At some point in the past, a river flowed over the field, depositing the rust on top of the granite.
C.
Exposure to acid precipitation has worn away the granite's exterior, revealing its soft interior.
D.
Snails and fungi living in the lava field have secreted chemicals that reacted with the granite to form rust.
Answer:
A. Exposure to air has caused the iron-bearing minerals in the granite to oxidize.
Explanation:
The main cause of granite rust is a metal substance that remains in it's contact over a long period of time. As a result of a moist or wet environment, . a geologist discovers a piece of granite that has a coating of soft, crumbling rust.
Exposure to air has caused the iron-bearing minerals in the granite to oxidize.
Option A. is correct.
How many protons are in an element with an atomic number of 8 anda mass number of 18?
3
8
10
18
Answer: 8
Explanation:
The atomic number of an element refers to the number of protons that it has in its nucleus. Carbon for instance has an atomic number of 6 because there are 6 protons in its nucleus.
This atomic number will also tell you the number of electrons the element (in its neutral state) has because protons and electrons are the same number. The reason the mass number is 18 in this scenario is that the element has 10 neutrons in its nucleus.
When hydrogen reacts with calcium metal, what are the oxidation numbers of the calcium and hydrogen in the CaH2 product?
Ca(s)+ H2(g) → CaH2
a. +2 and -1
b. +1 and -2
c. +2 and 2
d. 0 and 0
e. -2 and +1
Answer: e. -2 and +1
Explanation:
Oxidation number or oxidation state : It represent the number of electrons lost or gained by the atoms of an element in a compound.
Oxidation reaction is defined as the reaction in which a substance looses its electrons. The oxidation number of the substance increases.
Reduction reaction is defined as the reaction in which a substance gains electrons. The oxidation number of the substance gets reduced.
[tex]Ca(s)+H_2(g)\rightarrow CaH_2[/tex]
The oxidation number of calcium (Ca) in free state is 0 and in [tex]CaH_2[/tex] , it is -2.
The oxidation number of hydrogen in [tex]H_2[/tex] is zero and oxidation number of hydrogen in [tex]CaH_2[/tex] is +1 as in hydrides hydrogen loses electrons.
The oxidation number of calcium has been +2, and the oxidation number of hydrogen has been -1. Thus, the correct option is A.
The oxidation number can be defined as the number of electrons that have been lost by an atom in a chemical reaction.
The oxidation number can be calculated as the:
The oxidation number of Hydrogen when it combines with the less electronegative element has been -1.
There have been 2 atoms of Hydrogen that lose an electron, thus the total oxidation contribution of hydrogen has been -2.
The oxidation number of hydrogen has been -1.
The oxidation number of Calcium has been:
Ca atom has taken an electron from the hydrogen.
[tex]\rm Ca\;+\;e^-\;\rightarrow\;Ca^-[/tex]
The calcium takes one electron from each atom bonded. Thus the oxidation number of calcium has been +2.
The oxidation number of calcium has been +2, and the oxidation number of hydrogen has been -1. Thus, the correct option is A.
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Middle School Science help please. ill give brainliest
Answer:
its c
Explanation:
a compound has an empirical formula of C7H12O and a formula mass of 224g. what is the compound molecular formula
Explanation:
fyuvgddykhadkxdiyflhdfhyddkgd
Scan the list below for explanations of how
scientists applied knowledge of gecko feet to
produce an adhesive. Click each way that you
included in your response.
The researchers created an adhesive made
from carbon nanotubes.
The adhesive is made up of two different
layers.
The lower layer is made up of vertically
aligned nanotubes.
The upper layer is made up of curly, spaghetti
like, nanotubes.
Answer:
its the last 3...
Explanation:
the adhesive is made up of 2 different layers.
the lower layer is made up of vertically aligned nanotubes.
the upper layer is made up of curly, spaghetti like, nanotubes.
Perform the following
mathematical operation, and
report the answer to the
appropriate number of
significant figures.
15.673 + 14.752 + 8.4568 = [?]
Answer:
38.882
Explanation:
For all those Acellus kids XD
How many milliliters of 0.128 M nitric acid are required to neutralize 11.1 mL of 0.184 M sodium hydroxide? Answer with the correct number of significant digits.
Answer:
I think 7.72 mL
11.1/184 × 128/184=7.72
1. Which of the following is one impact that volcanoes had on the early earth?
A. Volcanoes had no impacts on planet earth but they are pretty and fun to learn about
B. Volcanoes released carbon dioxide into the atmosphere and this allowed for the evolution of oxygen-
breathing life forms
C. Volcanoes released oxygen into the atmosphere and this allowed for the evolution of oxygen-breathing
life forms
D. Volcanoes absorbed water vapor from the atmosphere and made the planet very dry and difficult to live
on
Answer:
B. Volcanoes released carbon dioxide into the atmosphere and this allowed for the evolution of oxygen-
breathing life forms
Explanation:
Volcanoes are a major source of carbon dioxide and global warming
Volcanoes absorbed water vapor from the atmosphere and made the planet very dry and difficult to live on, the impact that volcanoes had on the early earth.
What is volcanoes ?A volcano is a crack in a planet's crust, such as the one on Earth, that permits hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. Most volcanoes on Earth are located underwater, and they are most frequently found where tectonic plates are diverging or convergent.
The tectonic plates are drifting apart along constructive plate boundaries. To open a fresh passageway for rising hot magma to move on to the surface, the Earth's crust is split apart.
Volcanoes erupt with a tremendously destructive mixture of ash, lava, hot, toxic gases, and rock. Explosions from volcanoes have claimed lives.
Thus, option D is correct.
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HELPPPPP WILL MARK BRAINLIEST
Which are advantages of reflecting telescopes? Check all that apply.
A)There is no rainbow-like halo around the image.
B)Reflecting telescopes can be made very large.
C)Reflecting telescopes use only lenses, not mirrors.
D)Only the reflecting side of the primary mirror needs to be perfectly shaped and smooth.
E)The eyepiece creates an image for the observer.
Answer: a.b.d
Explanation:
Answer:
A)There is no rainbow-like halo around the image. Yes
B)Reflecting telescopes can be made very large. Yes
C)Reflecting telescopes use only lenses, not mirrors. No
D)Only the reflecting side of the primary mirror needs to be perfectly shaped and smooth. Yes
E)The eyepiece creates an image for the observer. No
Refer to the radioisotope colbalt-60, which has a half life of 5.3 years. An initial sample of colbalt-60 has an activity of 12,400cpm. How much time has passed if the activity of the sample has dropped to 775cpm
Answer:
21.2 years
Explanation:
If half life is 5.3 years, that means activity will be 50% every 5.3 years.
12,400 x 50% = 6,200
6,200 x 50% = 3,100
3,100 x 50% = 1,550
1,550 x 50% = 775
4 half lives, so 4 half lives x 5.3 years/half life = 21.2 years
Hello there, recently I was watching the movie Lights Out and I noticed that Diana, the ghost which the movie is about, burns when her skin goes in contact with any light but UV. Can someone explain how is she immune to UV light?
Answer:
maybe it does not affect her because uv light is different and has a different reaction to it
Explanation:
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a.liver e.mouth i.stomach
b.colon f.pancreas
j.large intestine c.gallbladder
g.tongue k.villi d.esophagus
h.peristalsis l.teeth
_8. stores a substance called bile, which physically breaks down fat droplets
_9. Digestion begins when salivary gland secretions enter this
_10. Minute projection extending from the walls of the small intestine and involved in absorbing products of digestion
_11. used to cut, tear, and grind food; adult has 32
_12. when you swallow food, muscular movements carry the food along this structure
to the stomach
13. this organ absorbs excess water form undigested food prior to its release from
the body as a solid waste
_14. Muscular movement involving the walls of the digestive tract that serve to mix materials and move them along the tract
15. it pushes food to the back of the mouth prior to swallowing
_16. this organ produces bile and detoxifies a variety of substances
_17. produces digestive juices that are released into the small intestine
_18. another name for the large intestine
19. functions include mixing food and serving as a reservoir prior to the food being passed on to the small intestine
Answer:
8. c
9. e
10. k
11. L
12. d
13. j
14. h
15. g
16. a
17. F
18. b
19. i
Explanation:
The gallbladder stores a substance called bile, which physically breaks down fat droplets, hence the correct options are 8. C, 9. E, 10. K, 11. L, 12. D, 13. J, 14. H, 15. G, 16. A, 17. F, 18. B, 19. I.
What are the components of the digestive system?Digestion begins when salivary gland secretions enter the mouth. Teeth used to cut, tear, and grind food; adult has 32.
Villi are a minute projection extending from the walls of the small intestine and involved in absorbing products of digestion.
When you swallow food, muscular movements carry the food along the esophagus to the stomach. The large intestine absorbs excess water from undigested food prior to its release from the body as a solid waste.
Muscular movement known as peristalsis involving the walls of the digestive tract that serve to mix materials and move them along the tract.
Therefore, the correct options are 8. C, 9. E, 10. K, 11. L, 12. D, 13. J, 14. H, 15. G, 16. A, 17. F, 18. B, 19. I.
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Question 3 Multiple Choice Worth 1 points)
(01.06 MC)
The contents of two beakers are described in the table.
Contents of Beakers
Beaker
Contents
Final Substance Formed
х
sugar, water sugar not visible in water
Y
sand, water sand settled at the bottom of the beaker
Which statement is true about the final substances formed in the beakers?
The final substances in both the beakers are mixtures.
The final substances in both the beakers are pure substances.
The final substance in Beaker X is a pure substance and in Beaker Y is a mixture.
The final substance in Beaker X is a mixture and in Beaker Y is a pure substance.
Answer:
the asnwer is B
Explanation:
The contents of two beakers X sugar, water sugar not visible in water Y sand, water sand settled at the bottom of the beaker final substance in Beaker X is a pure substance and in Beaker Y is a mixture. option C is correct.
What is mixture and pure substance?A mixture is a material made up of of two or more substances and this type of material can be compounds or chemical elements or mixture of liquids, solids, or gases can be produced.
A pure substance is the homogeneous mixture of two of more components is called the pure substance an if components are 2, 3, or 4 in number then the solution will be binary , tri-nary or quaternary.
Therefore, contents of two beakers X sugar, water sugar not visible in water Y sand, water sand settled at the bottom of the beaker final substance in Beaker X is a pure substance and in Beaker Y is a mixture. option C is correct.
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23. The compound which contains both ionic and covalent compound is
a)CH4
b) H2
c)KCN
d)KCL
Calcium carbonate is another example of a compound with both ionic and covalent bonds. Here calcium acts as the cation, with the carbonate species as the anion. These species share an ionic bond, while the carbon and oxygen atoms in carbonate are covalently bonded.
Answer:
D and C
Explanation:
KCl
because potassium ion ( K† ) is ionic and Chloride ion ( Cl- ) is covalent.
also KCN can be an alternative answer because the potassium ion ( K† ) is ionic and Cyanide ion ( CN- ) is covalent.
When would sediment get deposited in a stream
Answer:
When it's gradient decreases
freezing a sealed full bottl of water leads to a broken bottle and freezing a sealed full flexible wall container of n butyl alcholol leads to a container with concave walls, what can you conclude about the densitiies of the solid and liquid forms of these two substances
Answer:
See explanation
Explanation:
We know that water begins to expand at 4°C. This is generally referred to as the anomalous behavior of water.
The implication of this is that ice has a greater volume than water. Thus ice is less dense than liquid water.
n-butyl alcohol has much less density than water. This accounts for the fact that water upon freezing breaks the bottle while n butyl alcholol leads to a container with concave walls.
Hence the density of ice is much higher than the density of n butyl alcohol.
Based on the octet rule, nitrogen most likely forms a __ion.
a) N3+
b) N3-
d) N2+
c) N2
Answer:
b) N3-
Explanation:
The octet rule stipulates that a chemical specie is stable if it has eight electrons in its outermost shell.
Nitrogen belongs to group 15. This means that it has five electrons in its outermost shell. The formation N3- means that it accepted three electrons.
This brings the total number of outermost electrons to eight in accordance with the octet rule.
throwing a snowball during a snowball fight is most like an example of r. weather s. erosion t. deposition. v. acumulation
Answer:
V. accumulation
Explanation:
because the snow had to accumulate enough in order to make a snowball
Throwing a snowball during a snowball fight is most like an example of accumulation.
Accumulation refers to the gradual gathering of matter. This occurs overtime and may be as a result of events such as erosion. In a snowball fight, people throw snowballs at each other and the snowball eventually accumulates during the game.
Hence, throwing a snowball during a snowball fight is most like an example of accumulation.
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If the compound below is oxidized, the resulting product is:______CH3--CH2--CH2--CO--Ha) methane and propane b) butanal c) butanoic acid d) butane
Answer:
Butanal
Explanation:
alkanes are not oxidized
Carboxylic acids cannot be oxidized
Alkanals can be oxidized
18. What is the percent by mass sugar of a solution made by dissolving 12.45 grams of sugar in 100 grams of water?
The percent by mass sugar of a solution : 11.07%
Further explanationGiven
mass of sugar = 12.45 g
mass of water = 100 g
Required
The percent by mass
Solution
Mass of solution :
[tex]\tt mass~sugar+mass~water=12.45+100=112.45~g[/tex]
Percent mass of sugar :
[tex]\tt \%mass=\dfrac{mass~sugar}{mass~solution}\times 100\%\\\\\%mass=\dfrac{12.45}{112.45}\times 100\%=11.07\%[/tex]
Name the following compound: S₂O₇
Answer:
disulfur heptoxide
Explanation: