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.
Name the following compound: S₂O₇
Answer:
disulfur heptoxide
Explanation:
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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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]
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".
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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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
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.
The strongest bases have pH values close to
Answer:
Explanyour mmation:
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.
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
Help as soon as possible please tell why you chose A B C OR D
Answer: the answer is A
Explanation:
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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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
Middle School Science help please. ill give brainliest
Answer:
its c
Explanation:
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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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:
can i have brainest please
a compound has an empirical formula of C7H12O and a formula mass of 224g. what is the compound molecular formula
Explanation:
fyuvgddykhadkxdiyflhdfhyddkgd
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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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.
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
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
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]
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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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.
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
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
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