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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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 compound has an empirical formula of C7H12O and a formula mass of 224g. what is the compound molecular formula
Explanation:
fyuvgddykhadkxdiyflhdfhyddkgd
This giving, (or receiving or sharing) of electrons is called a bond.
So the bigger atoms (at the bottoms of Groups 1 and 2) in the first groups of the Periodic Table lose their outer electrons more easily forming bonds with nonmetals. This kind of bond is called an ______________ bond.
Answer:
Covalent bond
Explanation:
I am pretty sure this is the answer
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]
Iodine-131 is a radioactive material that plays a role in natural gas production and has a half-life of 8 days. A 320-mg sample of iodine-131 will decay to 250 mg after approximately days.
Time of decays approximately 2.853 days
Further explanationGiven
mass = 320mg iodine-131
No=320 mg
Nt=250 mg
t1/2 = 8 days
Required
t=time of decays
Solution
General formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]
Input the value
[tex]\tt 250=320.\dfrac{1}{2}^{t/8}\\\\log\dfrac{25}{30}=t/8.log~0.5\rightarrow t=2.853~days[/tex]
2.
Which provides evidence for evolution?
A. modern organisms closely resembling fossils
B. different animals developing with the same patterns
C. multiple species growing in very different ways
D. different animals having very different body structures
Answer:
A. modern organisms closely resembling fossils
Explanation:
Fossils are defined as the preserved remains or traces of living organisms from past.
Fossils are considered as an evidence for evolution because they represent the existence of life on earth and shows the difference between the life in past that life on earth today. With the help of fossil, it is easy to determine the age of fossils which further help to determine that how modern organisms have evolved from the past.
Hence, the correct answer is "A. modern organisms closely resembling fossils".
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:
can i have brainest please
How does the particle motion and behavior affect how a substance appears on a macroscopic level use the term solid liquid gas state of matter and particle motion in your answer
Answer:Long-term drug abuse changes areas in the brain that affect behavior, judgment, learning and memory
Explanation:
What happens when Magnesium hydroxide is heated? (Decomposition)
Answer:
It will make magnesium oxide and water
Explanation:
How can you avoid the formation of a supersaturated solution?
How to make super saturated solution?
An aqueous solution can be rendered supersaturated by first dissolving the solute in water at an elevated temperature using enough to give a concentration just under its solubility at that temperature. After the last of the solute crystals have dissolved the solution is cooled.
Answer:
By adding water i guess
Which of the following factors affect the rate of weathering in an area?
A.
climate
B.
topography
C.
rock composition
D.
all of the above
Answer:
D
Explanation:
pretty sure D
How many joules are needed to change the temperate of 22g of water from 18°C to 33°C?
Answer:
Q = 1379.4 J
Explanation:
Given data:
Mass of water = 22 g
Initial temperature = 18°C
Final temperature = 33°C
Heat absorbed = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
Specific heat capacity of water is 4.18 J/g. °C
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 = 33°C - 18 °C
ΔT = 15°C
Q = 522 g ×4.18 J/g.°C× 15°C
Q = 1379.4 J
Write a balanced chemical equation describing the oxidation of the bromide ion by solid xenon trioxide to produce bromine liquid and xenon gas in an acidic aqueous solution. Use the smallest whole-number coefficients possible.
Answer:
6Br⁻ + XeO₃ + 6H⁺ → 3Br₂ + Xe + 3H₂O
Explanation:
First, we need to write the half-reactions:
2Br⁻ → Br₂ + 2e⁻ Oxidation -Balanced yet-
XeO₃ → Xe Reduction
To balance the reduction in acidic aqueous solution we need to add waters in the other side of the reaction as oxygens are present:
XeO₃ → Xe + 3H₂O
And H⁺ as hydrogens from water we have:
XeO₃ + 6H⁺ → Xe + 3H₂O
To balance the charge:
XeO₃ + 6H⁺ + 6e⁻ → Xe + 3H₂O Reduction -Balanced-To cancel out the electrons of both half-reaction we need to multiply oxidation 3 times:
6Br⁻ → 3Br₂ + 6e⁻
XeO₃ + 6H⁺ + 6e⁻ → Xe + 3H₂O
And the balanced reaction in acidic aqueous solution is the sum of both half-reactions:
6Br⁻ + XeO₃ + 6H⁺ → 3Br₂ + Xe + 3H₂OWhile 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.
Middle School Science help please. ill give brainliest
Answer:
its c
Explanation:
1. True or false ? Balanced forces cause a change in motion. How do you know this ?
2. True or false ? Unbalanced forces cause a change in motion? How do you know this ?
Answer:
1. False
Balanced forces would mean all forces acting upon an object would be equal. So there is no movement.
2. True
Unbalanced forces would mean there is a force acting upon a side of tge object, causing it to move in a direction.
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
Place the following in order of increasing X-Se-X bond angle, where X represents the outer atoms 7) in each molecule. SeO2 SeCl6 SeF2
A) SeF2 SeO2< SeCl6
B) Seo2
C) SeF2 < SeCl6 SeO2
D) SeCl6 < SeF2 Se02
Answer:
SeCl₆ < SeF₂ < SeO₂
Explanation:
To determine the order of the bond angle of the compound, we need to determine the hybridization of each compound given.
For:
SeO₂, The hybridization is sp² because the Se is doubly bonded to O at both sides and Se contains a lone pair of electrons.
SeCl₆, Se is attached to six different Cl atoms via a single bond in a hexagonal shape. Thus, SeCl₆ hybridization is sp³d²
SeF₂, Here, Se is singly bonded to F atoms on both sides and Se contains a lone pair of electrons. The hybridization is sp³
Therefore, the bond angle in sp² = 120°, sp³ = 109.8°, sp³d² = 90°
Hence, the order is: SeCl₆ < SeF₂ < SeO₂
What is the speed of a car that moves 12 meters in 3 seconds? (Don't forget the unit!)
Answer:
8.9 mph
Explanation:
Which statement summarizes the law of superposition? A. The oldest rock is found in the bottom layer of a rock formation. B. The rarest elements are found in the lowest layer of a rock formation. O C. The densest layer of rock in a rock formation is the bottom layer. D. The top layer of rock in a rock formation is the oldest. SUBMIT e
Answer:
A superposition says that the newest rocks are nearer to the surface and oldest are near the bottom
Answer:
A.
Explanation:
7.
Which characteristic is comaon of developing countries?
A
B
C
D.
Slower growth rate
longer life expectancy
lower fertility rate
higher infant mortality
Slower growth rate is common characteristic of developing countries. Therefore, the correct option is option A.
What is developing countries?A sovereign state that is considered to be developing has a less developed industrial base with an HDI that is lower than other nations. This term is not generally accepted, though. Furthermore, there is no consensus on which nations fall into this category.
Although the phrase "low and middle-income country" (LMIC) is sometimes used synonymously, it only relates to the economies of the nations. In accordance with gross national income per capita, the World Bank divides the world's economy into four categories: high, upper-middle, lower-middle, as well as low income countries. Slower growth rate is common characteristic of developing countries.
Therefore, the correct option is option A.
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7. Explain why ethylated spirit at room temperature when dropped at the back of the palm makes
the palm to feel very cold.
(2 Marks)
Answer:
Evaporation is very important in the cooling of surfaces. If we put a drop of methylated spirit on our hand the methylated spirit will soon evaporate and our hand feels cold. The molecules of methylated spirit get the energy they need from our hand, leaving the molecules of the hand with less energy and so colder.
The ethylated sprit starts to evaporate from our hand. Evaporation is an endothermic process thus, absorbs the heat energy from our hand make the surface cool.
What is an endothermic process?An endothermic process is the one which absorbs energy from the surroundings to proceed. Thus, an endothermic process make the surroundings cool and make the reaction system hot.
The process which evolves heat energy is called an exothermic process. An exothermic reaction make the surroundings hot sometimes leads to explosion.
Evaporation is the process of conversion of a liquid substance into vapor form. This process needs energy to intake. Hence during evaporation, the heat energy is absorbed from the surroundings make there cool. This is just happening on our hand when sprit evaporates.
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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.
The strongest bases have pH values close to
Answer:
Explanyour mmation:
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
complete the sentence using oxalate, oxic or oxide
A binary ionic compound with the formula Feo
would be named iron(II)_____
Answer: oxide
Explanation:..
When would sediment get deposited in a stream
Answer:
When it's gradient decreases
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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Help as soon as possible please tell why you chose A B C OR D
Answer: the answer is A
Explanation:
4. What is valency? Explain different types of
valencies
Answer:
Valency is the combining power of an element.
There are two types of valency - Electrovalency and Covalency.
Electrovalency: It is equal to the number of electrons lost or gained by atom to form ion.Covalency: It is the number of electron taking part in the formation of shared pairs.Hope it helps!<3