Complete question is;
Which statements accurately describe the evidence that scientists gather using fossils? Check all that apply.
A) The fossil record can be used to date rocks.
B) Living things with many cells have always lived on Earth.
C) Simple organisms are found only in young rocks.
D) Geologists study ancient remains of plants and animals.
E) Scientists can figure out what ancient living things ate.
F) Pollen and seeds help provide clues about ancient climates.
Answer:
A) The fossil record can be used to date rocks
E) Scientists can figure out what ancient living things ate.
F) Pollen and seeds help provide clues about ancient climates
Explanation:
In scientific research, fossils are sometimes referred to as animals and plant. Now, in studying records of fossils, it will be easy to know the length of existence of living things on the Earth. Also, we can be able to identify the manner in which different relationships exists between plants and animals by predicting their lifestyles, location of their habitation e.t.c which can be used to predict the old time climates.
Looking at the options given in relation to the explanation given, options A, E & F are correct
Which is the electron configuration for lithium?
1s2
2s3
1s22s1
1s12s2
Answer:
1s2, 2s1
Explanation:
Lithium is the first element in the 2nd row of elements meaning its 1s orbital is completely filled and 1 electron is in the 2s orbital.
Answer:
the answer is C
Explanation:
What is the mass percent of a sodium fluoride solution prepared by dissolving 0.64 moles of sodium fluoride into 63.5 grams of water?
The mass percent of a sodium fluoride solution prepared by dissolving 0.64 moles of sodium fluoride into 63.5 grams of water is 29.7%.
What is mass percent ?Mass percent is a means to describe a component in a specific combination or to convey a concentration. The mass percentage used to describe the solution composition indicates the mass of solute contained in a given mass of solution.
To determine the mass percent of an element in a compound, we divide the mass of the element in one mole of the compound by the compound's molar mass and multiply the result by 100.
Given:
Number of moles = 0.64 moles
Moles of sodium fluoride = Given mass/molar mass
0.64 moles = Mass / 42
Mass = 26.88gram
Mass % = Mass of solute/ mass of solution × 100
= 26.88/90.48 × 100
= 29.7 %
Thus, 29.7 % is the mass percent of a sodium fluoride solution prepared by dissolving 0.64 moles of sodium fluoride into 63.5 grams of water
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Can compound take part in chemical reaction?
Answer:
YES!
Explanation:
What is the pressure in atm exerted by 1.8 g of H2 gas exert in a 4.3 L balloon at 27ºC? R = 0.821(L*atm) / (mol*K)
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The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm
What is Ideal gas law ?The ideal gas law (PV = nRT) relates the macroscopic properties of ideal gases. An ideal gas is a gas in which the particles (a) do not attract or repel one another and (b) take up no space (have no volume).
Let's convert grams to moles (via molar mass).
Molar Mass (H₂) : 2 (1.008 g/mol)
Molar Mass (H₂) : 2.016 g/mol
1.8 grams H₂ 1 mole
---------------------- x ---------------------- = 0.893 moles H₂
2.016 grams
The Ideal Gas Law equation looks like this:
PV = nRT
In this equation,
P = pressure (atm) V = volume (L) n = moles R = Ideal Gas Constant (0.0821 L*atm/mol*K)T = temperature (K)After converting Celsius to Kelvin, you can put the given values into the equation and simplify to find the pressure.
P = ? atm R = 0.0821 L*atm/mol*K
V = 4.3 L T = 27 °C + 273.15 = 300.15 K
n = 0.893 moles
PV = nRT
P (4.3 L) = (0.893 moles) (0.0821 L*atm/mol*K)( 300.15 K)
P (4.3 L) = 22.0021
P = 5.12 atm
Therefore, The pressure in atm exerted by 1.8 g of H₂ gas exert in a 4.3 L balloon at 27ºC is 5.12 atm
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Give the structural formula of CH3CH(CH3)CH3
In the structure, we essentially have a Carbon with 3 methyl groups and a hydrogen attached to it
What is the purpose of a catalyst in the production of hydrogen?
Select the correct answer.
- to increase the rate at which water molecules decompose
- to decrease the amount of oxygen produced
- to decrease the temperature of the reaction
- to increase the activation energy of the reaction
The purpose of a catalyst in the production of hydrogen is to increase the rate at which water molecules decompose.
What is a catalyst-A catalyst is a substance that increases the rate of a chemical reaction without itself being consumed or produced during the reaction. As a result, catalysts assist in speeding up chemical reactions while also decreasing the amount of energy needed for the reaction to occur. In hydrogen production, catalysts are used to speed up the decomposition of water into hydrogen and oxygen. The use of catalysts lowers the activation energy required for the reaction to occur, resulting in a faster reaction rate and lower operating temperatures.What is the process of hydrogen production?Hydrogen production has various methods, and one of the most commonly used methods is water electrolysis. In this method, water molecules are split into hydrogen and oxygen using an electric current passed through an electrode. Water is broken down into hydrogen and oxygen during the process, with the assistance of a catalyst. During this process, a catalyst like platinum or nickel is employed to speed up the chemical reaction of water decomposition.
When an electric current is applied to the catalyst, water molecules are broken apart, releasing hydrogen and oxygen atoms.Catalysts lower the activation energy of the reaction, allowing it to occur faster than it would otherwise. In hydrogen production, catalysts are crucial since they enable the reaction to occur at a lower temperature, reducing energy consumption and minimizing operating costs. As a result, the use of catalysts is essential to the production of hydrogen.
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g) silver nitrate + magnesium chloride → silver chloride + magnesium nitrate
Answer:
AgNo3+Mgcl2--->Agcl2+Mg(No3)2
I hope this helps
c. The element in group 2 and period 3 is -
Answer:
Magnesium
Explanation:
Hope this helps!
In the figure a cyclist moves A to B and then to C.he could also go through the shortest path AC. Depending on this fact solve the following questions: Find the length of AC .Find the displacement and total distance covered.
Answer:
hope it helps you see the attachment for further information
what is the percentage composition of water in crystallization of oxalic acid
Answer:
5.17 percentage is water
Explanation:
answer from gauth math
Describe what happens to the particles when a substance:
1. Melts
2. Freezes
3. Boils
4. Condenses
Question 5
1.00 g of He, 14.0g F2, and 19.0 g Ar are placed in a 13.0-L container at 20.0 °C.
The total pressure (in atm) in the container is _____ atm.
1 point
Answer:
2.03 atm
Explanation:
Number of moles of He = 1g/4g/mol = 0.25 moles
Number of moles of F2 = 14.0g/38 g/mol = 0.37 moles
Number of moles of Ar=19.0g/40g/mol = 0.48 moles
Total number of moles = 0.25 + 0.37 + 0.48 = 1.1 moles
From;
PV=nRT
P= pressure of the gas mixture
V= volume of the gas mixture
n= total number of moles of the gas mixture
R= gas constant
T= temperature of the gas mixture
P= nRT/V
P= 1.1 × 0.082 × 293/13
P= 2.03 atm
Explain Froath Flotation Method!
Explanation:
a process for separating minerals from gangue by taking advantage of the differences in their hydrophobicity.
I believe that is accurate
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The world is made up of
Answer:
Explanation:
The world is made up of living beings .
write any two conditions at which a body of certain mass weightless
Answer:
A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity. If the body is falling only under the influence of gravity.
Answer:
A body becomes weightless in a zero-gravity scenario and when a force is applied to a body that is equal and opposite to the force of gravity.If the body is falling only under the influence of gravity.
Một hỗn hợp X gồm CH3OH; C2H5OH; phenol có khối lượng 28,9 gam phản ứng vừa hết với 100ml dung dịch NaOH 2M. Phần trăm theo khối lượng phenol là ? Biết C = 12; O = 16; H = 1; Na = 23. *
Answer: bạn viết phương trình Phenol + NaOH
=> nNaOH = nPhenol = 0,2 mol
m Phenol = 0,2x94 = 18,8 gam
%mPhenol = 18,8/28,9% = 65,05
Explanation:
can you answer with working out
Specific heat capacity is _____.
greater for metal than for wood
the amount of heat required to raise the temperature of 1g of a substance 1 oC
represented by the symbol, Q
all of these
Answer:
all of this
Explanation:
How much water will the measuring cup have if you poured 1/2 of it out?
- calculate relative formula mass
[N=14, O=16, Mg=24, Al=27]
1) Mg(NO3)2
- calculate relative molecular mass
[H=1, C=12, O=16]
1) C4H10
2) CH3COOH
Mg(NO3)2:-
[tex] \\ \sf \longmapsto \: 24u+2(14u+3\times 16u)[/tex]
[tex] \\ \sf \longmapsto \: 24u+2(14u+48u)[/tex]
[tex]\\ \sf \longmapsto \: 24u+2(62u)[/tex]
[tex] \\ \sf \longmapsto \: 24u+(124u)[/tex]
[tex] \\ \sf \longmapsto \: 148u[/tex]
How is a slump different from creep?
Answer:
Is this chemistry or ELA!
Determine the mass of 6.33 mol of iron(II) nitrate.
Answer:
1822.72 g
Explanation:
Applying,
n = R.M/M.M.................. Equation 1
Where n = number of moles of iron(II) nitrate, R.M = Reacting mass of iron(II) nitrate, M.M = molar mass of Iron(II) nitrate.
Make R.M the subject of the equation
R.M = n×M.M............. Equation 2
From the question,
Given: n = 6.33 mol
Constant: M.M of iron(II) nitrate = 287.95 g/mol
Substitute these values into equation 2
R.M = 6.33(287.95)
R.M = 1822.72 g
Hence the mass of iron(II) nitrate is 1822.72 g
the text of oxygen gas in the laboratory
Explanation:in testing for oxygen a glowing splint is used.
the glowing splint is brought in the presence of the test tube containing the gas
the glowing splint rekindles or lights up showing that oxygen is present.
this is a positive test because oxygen supports burning or combustion
5. The energy diagram shown illustrates a reaction which is
an
A. exothermic reaction.
B. activated complex.
C. equilibrium reaction.
D. endothermic reaction.
Answer:
Explanation:
The answer is an exothermic reaction so A.
You work in the special effects department of a movie studio. You are currently working on a superhero movie where the hero is very strong and cannot be hurt by normal weapons such as a sword. In the next scene, the villain is going to hit the hero with a lead pipe. The hero's costume is mostly made of foam and carbon so that is it very light and easy to move around in but will crumble if hit with anything hard. For this scene, a section of the costume needs to be replaced with a different material that will only dent, not crumble, when hit with the pipe. You are on a deadline and look around the props department for ideas, what could you use?
Answer:
Aluminum or Galvanized iron
Explanation:
If the costume has to be such that the hero does not get hurt when hit by a lead rod and also is easy for the mobility then the suitable option for the costume could be Aluminum material which will only dent and not crumble.
Galvanized iron could be another choice being harder and stronger as compared to aluminum but a little heavy. It can sustain heavy impacts as compared to aluminum.
Answer:
You could use a shield if you are not speaking from a scientific way.
Which of the following is an example of a solution?
A. An iron alloy
B. Iron metal
C. Iron rust
D. An iron ore
Answer:
A: an iron alloy.
Explanation:
Because iron alloy consists of minor components that are distributed within the major component, which is the basic requirement for a solution.
PLZ HELP Question 2 of 25 What is the total number of atoms in the molecule CzHg?
A. 2
B. 8
C. 11
D. 3
A. 2
One Cs (Caesium), the other one Hg (Mercury)
Note: we don't have Cz this might be Cs
How does a cirrus cloud look like
1) cotton
2) thin feather
Answer:
2) thin feather
Explanation:
Cirrus clouds are delicate, feathery clouds that are made mostly of ice crystals. Their wispy shape comes from wind currents which twist and spread the ice crystals into strands.
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which of the following is a physical change? 1.burning paper 2.grinding wheat 3.electrolysis of water 4.cooking rice
Answer:
2 grinding of wheat is just a physical change
plz brainlist
High-pressure liquid chromatography (HPLC) is a method used in chemistry and biochemistry to
purify chemical substances. The pressures used in this procedure range from around 500
kilopascals (500,000 Pa) to about 60,000 kPa (60,000,000 Pa). It is often convenient to know
the pressure in torr. If an HPLC procedure is running at a pressure of 3.20x10^8 Pa , what is its
running pressure in torr?
Express the pressure numerically in torr.
►
3.20 x 10^8 Pa = _____ torr
Answer:
2,400,000 torr (3 s.f.)
Explanation:
Convert the pressure from Pascal to atm first:
[tex]\boxed{1 \: atm = 101325 \:Pa }[/tex]
3.20 ×10⁸ Pa
= [(3.20 ×10⁸) ÷101325] atm
= 3158.2 atm (5 s.f.)
Convert atm to torr:
[tex]\boxed{1 \: atm = 760 \: torr}[/tex]
3158.2 atm
= (3158.2 ×760) torr
= 2400000 torr (3 s.f.)
