Which statement is true about fossils?

a.Only the remains of animals, and not plant, can be made into a fossil.
b.To officially be a fossil, the remains of an entire organism must be found.
c.The remains of an organism that lived 500 years ago is called a fossil.
d.A fossil is any trace of prehistoric life.

Answers

Answer 1

Answer:

d, the remains of an organism have to be 10,000 years old to be classified as a fossile:)

Answer 2

Answer:

(d)

Explanation:took the quiz


Related Questions

Can somebody please help me!!!!

Answers

Answer and Explanation:

The answer is Motion.

We can see that part of the image is blurry, which shows that the fish are moving fast. Moving = motion, so that means the fish has motion.

#teamtrees #PAW (Plant And Water)

Answer:

motion

Explanation:

Please give me the answer please

Answers

Answer:

A. 30cm³

Explanation:

Based on the chemical reaction:

CaCO₃ + 2HCl → CaCl₂ + H₂O + CO₂

1 mol of calcium carbonate reacts with 2 moles of HCl to produce 1 mol of CO₂

To solve this question we must convert the mass of each reactant to moles. With the moles we can find limiting reactant and the moles of CO₂ produced. Using PV = nRT we can find the volume of the gas:

Moles CaCO₃ -Molar mass: 100.09g/mol-

1.00g * (1mol / 100.09g) = 9.991x10⁻³ moles

Moles HCl:

50cm³ = 0.0500dm³ * (0.05 mol / dm³) = 2.5x10⁻³ moles

For a complete reaction of 2.5x10⁻³ moles HCl there are necessaries:

2.5x10⁻³ moles HCl * (1mol CaCO₃ / 2mol HCl) = 1.25x10⁻³ moles CaCO₃. As there are 9.991x10⁻³ moles, HCl is limiting reactant.

The moles produced of CO₂ are:

2.5x10⁻³ moles HCl * (1mol CO₂ / 2mol HCl) = 1.25x10⁻³ moles CO₂

Using PV = nRT

Where P is pressure = 1atm assuming STP

V volume in L

n moles = 1.25x10⁻³ moles CO₂

R gas constant = 0.082atmL/molK

T = 273.15K at STP

V = nRT / P

1.25x10⁻³ moles * 0.082atmL/molK*273.15K / 1atm = V

0.028L = V

28cm³ = V

As 28cm³ ≈ 30cm³

Right option is:

A. 30cm³

A 31.0 mL sample of 0.624M perchloric acid is titrated with a 0.258M sodium hydroxide solution.

What is the (H+) molarity after the addition of 15.0 mL of KOH?

Answers

Answer:

0.0922 M

Explanation:

The problem first states that the titration is made using NaOH, and later asks about the addition of KOH. I'm going to assume NaOH was used throughout the whole problem. The result does not change if it was KOH instead.

The reaction that takes place is:

HClO₄ + NaOH → NaClO₄ + H₂O

First we calculate how many HClO₄ moles are there in the sample, using the given molarity and volume:

0.624 M * 13.0 mL = 8.11 mmol HClO₄

Then we calculate how many NaOH moles were added:

0.258 M * 15.0 mL = 3.87 mmol NaOH

Now we calculate how many HClO₄ remained after the reaction:

8.11 - 3.87 = 4.24 mmol HClO₄

As HClO₄ is a strong acid, 4.24 mmol HClO₄ = 4.24 mmol H⁺

Finally we calculate the molarity of H⁺, using the calculated number of moles and final volume:

Final volume = 31.0 mL + 15.0 mL = 46.0 mL4.24 mmol / 46.0 mL = 0.0922 M

almunium has a density of 2.70g/cm3. how many moles of aluminium are in a 13.2cm3 block of the metal substances?

Answers

Answer:

1.32 moles.

Explanation:

From the question given above, the following data were obtained:

Density of Al = 2.70 g/cm³

Volume of Al = 13.2 cm³

Number of mole of Al =.?

Next, we shall determine the mass of Al.

This can be obtained as follow:

Density of Al = 2.70 g/cm³

Volume of Al = 13.2 cm³

Mass of Al =?

Density = mass / volume

2.7 = mass of Al / 13.2

Cross multiply

Mass of Al = 2.7 × 13.2

Mass of Al = 35.64 g

Finally, we shall determine the number of mole of Al. This can be obtained as follow:

Mass of Al = 35.64 g

Molar mass of Al = 27 g/mol

Number of mole of Al =?

Mole = mass / molar mass

Number of mole of Al = 35.64 / 27

Number of mole of Al = 1.32 moles

Thus, 1.32 moles of aluminum are present in the block of the metal.

What scientifically goes on with a plasma ball?

Answers

Answer:

the electrode at the center of a plasma ball emits a high-frequency,high-voltage alternating electric current. This current flows through the plasma filaments to create colorful tendrils of light.

Explanation:

what colors depend upon the gases used inside the plasma ball? common gases include neon, argon, xenon, and krypton.

h20 (s) -> h20 (g)
endothermic or exothermic

Answers

Answer:

Endothermic.

Explanation:

Hello there!

In this case, it is necessary to keep in mind that exothermic processes are characterized by the release of energy and the endothermic processes by the absorption of heat. In such a way, every process from solid to liquid or gas is endothermic as they require energy to separate the molecules and therefore turn out in the phase change. On the other hand, every process from gas to liquid or solid is exothermic as heat is released to rejoin the molecules and produce the phase change.

Therefore, since solid water molecules tend to be well-arranged, it is necessary to add heat to the system to produce the phase change until gas; in such a way, this process is endothermic as energy must be absorbed by the ice.

Best regards!

How tightly particles are packed determines what state it takes.
True or False​

Answers

Answer:

True

Explanation:

tighter the molecules the slower it moves and the harder it gets

solid has very tight particles packed together

gas has its particles spread out

Can somebody please help me!!!

Answers

Answer:

javier applied force how this helps

Did you hear the one about a chemist who was reading a book about helium?

Answers

Answer: I had that before it's a riddle. Here lemme find it and give you the answer.

Explanation:

1.H

2.E

3.C

4.O

5.U

6.L

7.D

8.U

9.T

10.P

11. N

12.T

13.I

14.T

15.D

16.O

17.N

18.W

Helium is a type of chemical element which is a noble gas that does not have odor, color, taste and does not contain toxicity. It's atomic number is 2  and is chemically represented with "He"

As a result of this, there are some unique characteristics of the Helium element which includes:

Low boiling pointLow densityHigh thermal conductivityLow solubility, etc

Please note that your question is disjointed so I gave you a general overview to help you understand the concept

Read more here:

https://brainly.com/question/19099891

Complexes containing metals with d10 electron configurations are typically colorless because ________. Complexes containing metals with d10 electron configurations are typically colorless because ________. d electrons must be emitted by the complex in order for it to appear colored there are no d electrons to form bonds to ligands a complex must be charged to be colored there is no d electron that can be promoted via the absorption of visible light the empty d orbitals absorb all of the visible wavelengths

Answers

Answer:

there is no d electron that can be promoted via the absorption of visible light

Explanation:

One of the properties of transition elements is the possession of incompletely filled d orbitals. This property accounts for their unique colours.

The colours of transition metal compounds stem from d-d transition of electrons due to the presence of vacant d orbitals of appropriate energy to which electrons could be promoted.

For elements whose atoms have a d10 configuration, such vacant orbitals does not exist hence their compounds are not colored.

Sometimes, the colour of transition metal compounds stem from ligand to metal charge transfer(LMCT) for instance in KMnO4.

A gas that exerts a pressure of
15.6 psi in a container with a volume of
L will exert a pressure of
25.43 psi when transferred to a
container with a volume of 1.895 L.

Answers

Answer:

3.089 L

Explanation:

From the given information, provided that the no of moles and the temperature remains constant;

[tex]P_1[/tex] = 15.6 psi

[tex]V_1[/tex] = ???

[tex]P_2[/tex] = 25.43 psi

[tex]V_2[/tex] = 1.895 L

Using Boyle's law:

[tex]P_1V_1 =P_2V_2 \\ \\ V_1 = \dfrac{P_2V_2}{P_1} \\ \\ V_1 = \dfrac{25.43 \times 1.895}{15.6} \\ \\ \mathbf{ V_1 = 3.089 \ L}[/tex]

What is the volume of a 5.00 molar solution containing 20 moles of 0.40 10.0L 0.010L

Answers

Answer:

Volume of solution = 4 liter

Explanation:

Given:

Molarity = 5 M

Number of moles = 20 moles

Find:

Volume of solution

Computation:

Moles of solute mixed per litre of solution is known as molarity. A 1 M sample is the one in which 1 molecule of solvent is soluble in one liter of solution volume.

M = Mol / L

5 = 20 / L

Volume of solution = 4 liter

what is a chemical property​

Answers

Answer:

Chemical property is a characteristic of a particular substance that can be observed in a chemical reaction.

Explanation:

Hope this helps :)

Answer:

A chemical property is any of a material's propertiesthat becomes evident during, or after, a chemicalreaction; that is, any quality that can be established only by changing a substance's chemical identity. ... They can also be useful to identify an unknown substance or to separate or purify it from other substances.

why does oxygen and carbon dioxide travel within the seed and the egg

Answers

Answer: Inside the egg, oxygen is used by the chick as a source of energy and is turned into carbon dioxide. The carbon dioxide then leaves through the egg's shell. Oxygen enters through the egg's shell. Inside the egg, oxygen reacts with molecules from the yolk to release energy for the growth of the chick.

Aqueous hydrochloric acid will react with solid sodium hydroxide to produce aqueous sodium chloride and liquid water . Suppose 1.5 g of hydrochloric acid is mixed with 2.67 g of sodium hydroxide. Calculate the maximum mass of water that could be produced by the chemical reaction. Round your answer to significant digits.

Answers

Answer: The maximum amount of water that can be produced is 0.74 g

Explanation:

To calculate the number of moles, we use the equation:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]      .....(1)  

Putting values in equation 1, we get:

[tex]\text{Moles of hydrochloric acid:}=\frac{1.5g}{36.5g/mol}=0.041mol[/tex]

[tex]\text{Moles of sodium hydroxide}=\frac{2.67g}{40g/mol}=0.067mol[/tex]

The chemical equation for the reaction is

[tex]HCl+NaOH\rightarrow NaCl+H_2O[/tex]

By Stoichiometry of the reaction:

1 mole of HCl reacts with 1 mole of NaOH

So, 0.041 moles of HCl will react with = [tex]\frac{1}{1}\times 0.041=0.041mol[/tex] of NaOH

As, given amount of NaOH is more than the required amount. So, it is considered as an excess reagent. Thus, HCl is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of HCl produces = 1 mole of water

So, 0.041 moles of HCl will produce = [tex]\frac{1}{1}\times 0.041=0.041moles[/tex] of water

Mass of water=[tex]moles\times {\text{Molar Mass}}=0.041mol\times 18g/mol=0.74g[/tex]

Thus the maximum amount of water that can be produced is 0.74 g

How does the entropy change in the reaction 2C3H6(g) + 9O2(g) → 6C02(g) + 6H2O (g)?

I will mark brainliest!! Thank you so much!!

Answers

Answer:

The entropy increases!!!

Explanation:

a pex

The entropy increases in the reaction.

What is entropy?Entropy is defined as the measure of the disorder of a system.Entropy is an extensive property of a thermodynamic system, to put it in simple words, its value changes depending on the amount of matter that is present.Entropy is denoted by the letter S and has units of joules per kelvin    (JK−1)

The entropy increases in the reaction if the total number of product molecules are greater than the total number of reactant molecules.

2C3H6(g) + 9O2(g) → 6C02(g) + 6H2O (g)

In the above reaction, the product molecules are greater than the reactant molecules. Hence, entropy increases.

Hence, we can conclude that option A is the answer.

To learn more about entropy here

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#SPJ2

22.4 L is the volume of any gas regardless of atmospheric conditions.

O True

O False

Answers

This is false. One mole of a gas occupies 22.4 L at STP, which is taken to be 0°C (273 K) and 1 atm. If atmospheric conditions depart from these values, this assumption cannot be used.

How many grams of hydrogen gas are needed to completely react with excess nitrogen to produce 26.7 grams of ammonia (NH3)? N2 + H2 → NH3

Answers

Answer:

4.74 g H2

Explanation:

First, balance your reaction:

N2 + 3H2 --> 2NH3

Now convert 26.7 g NH3 to moles NH3 by dividing by its molar mass (17.031 g/mol). Then multiply by the mole ratio of 3 mol H2 for every 2 mol NH3 to get moles of H2. Finally multiply by the molar mass of H2 (2.016 g/mol) to get grams of H2.

26.7 g NH3 • (1 mol NH3 / 17.031 g NH3) • (3 mol H2 / 2 mol NH3) • (2.016 g H2 / 1 mol H2) = 4.74 g H2

what are possible source of error for rusting of a nail​

Answers

Answer:

A nail can rust when exposed to oxygen. the molecules of iron on the surface of the nail exchange atoms with the oxygen in the air and produce a new substance, the reddish brown ferrous oxide i.e rust.

Click on an olive tree and read about it. Based on what you read, do you think the climate of Barcelona is very wet or rather dry? Explain.

Answers

Answer:

In the Autumn, Spring, and Winter, It is wet. In the Summer it is dry.

Explanation:

state the conditions under which copper reacts with sulphuric (vi) acid and give an equation for the reaction​

Answers

Answer:

When the metal reacts with hot, concentrated sulphuric acid, the products of the reaction are copper (II) sulphate, sulphur dioxide and water. Cu + 2H2SO4 = CuSO4 + SO2 + 2H2O. This is a typical redox reaction in which the acid is reduced to SO2, but no hydrogen is produced here

with recessions government spending should


decrease

increase

or allowed to remain the same increased

Answers

Answer:

Increase to pay unemployment and get the economy back up

What volume of 0.215 M HCl is required to neutralize 50.0 mL of
0.800 M NaOH?

Answers

Answer:

186 mL HCl

Explanation:

M1V1 = M2V2

M1 = 0.215 M HCl

V1 = ?

M2 = 0.800 M NaOH

V2 = 50.0 mL

Solve for V1 --> V1 = M2V2/M1

V1 = (0.800 M)(50.0 mL) / (0.215 M) = 186 mL HCl

How many milliliters of 0.2560 M KCl solution will contain 20.00 g of KCl?
Answer is 1048 mL solution but how do I get to the answer?

Answers

Answer:

1048 mL

Explanation:

Step 1: Given data

Concentration of the solution: 0.2560 MMass of KCl (solute): 20.00 g

Step 2: Calculate the moles corresponding to 20.00 g of KCl

The molar mass of KCl is 74.55 g/mol.

20.00 g × 1 mol/74.55 g = 0.2683 mol

Step 3: Calculate the volume of the solution

Molarity is equal to moles of solute divided by liters of solution.

M = moles of solute / volume of solution

volume of solution = moles of solute / M

volume of solution = 0.2683 mol / (0.2560 mol/L)

volume of solution = 1.048 L = 1048 mL

What is the molarity of a solution containing 20moles of NaCl dissolved in 10 liters of water?
10 mol/L
2 mol/L
5mol/L
0.5 mol/L

Answers

m=20 moles
V=10 liters
M=?
M=moles (solute) / volume(L)
M= 20/10 = 2 mol/l

The molarity of a solution containing 20moles of NaCl dissolved in 10 liters of water is 2 mol/L.

How do we calculate molarity?

Molarity of any solution will be calculated by using the below formula:
M = n/V, where

n = moles of solute = 20 mol

V = volume of solution or solvent = 10 L

On putting values on above equation, we get

M = 20 / 10 = 2M

Hence required molarity of NaCl is 2 M.

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100 POINTS!!!!!!!
The following diagram shows the branching tree for four kingdoms and some of their shared derived characteristics.

A slanting line is shown. There are four lines drawn vertically on this line at equal intervals. There is a black circle between each pair of these vertical lines. Protists, Plants, Fungi, Animals are written on top of each vertical line in order from left to right. Common Cell is written on the left most end of the sloping line. The second black circle has Mostly Multicellular written on it. The first black circle has X written on it.

What shared characteristic can be written at point X? Use complete sentences to explain your answer.

Answers

Answer:

The answer could be "Autotrophs that photosynthesis".

Explanation:

At point X, the common characteristic can be written. The common character between protists and plants is autotrophs that photosynthesize which is the characteristic of plant-like protists. Plant-like protists are autotrophs, use carbon dioxide and water to produce glucose by the process of photosynthesis.

Nitric acid and nitrogen monoxide react to form nitrogen dioxide and water, like this: (aq)(g)(g)(l) At a certain temperature, a chemist finds that a reaction vessel containing a mixture of nitric acid, nitrogen monoxide, nitrogen dioxide, and water at equilibrium has the following composition: compoundamount Calculate the value of the equilibrium constant for this reaction. Round your answer to significant digits.

Answers

Answer:

The reaction given is  

Chemistry homework question answer, step 1, image 1

Since in equilibrium constant expression, the concentration of liquid components is not written.

Hence the equilibrium constant expression for the above reaction can be written as  

Chemistry homework question answer, step 1, image 2

where [NO] = equilibrium concentration of NO

[NO2 ] = equilibrium concentration of NO2

[HNO3 ] = equilibrium concentration of HNO3

Step 2

Given : mass of NO at equilibrium = 18.6 g

mass of NO2 at equilibrium = 15.1 g

and mass of HNO3 at equilibrium = 13.1 g

Since molar mass of HNO3 = 63 g/mol, molar mass of NO = 30 g/mol and molar mass of NO2 = 46 g/mol

Hence the moles of gases at equilibrium are

Chemistry homework question answer, step 2, image 1

Step 3

Since mass of solution = mass of HNO3 + mass of water = 13.1 + 234.8 = 247.9 g

Assuming density of solution = density of water = 1.00 g/mL

=> mass of solution = volume of solution X density of solution  

=> 247.9 = 1.00 X volume of solution  

=> volume of solution = 247.9 mL = 0.2479 L      

Explanation:

different between intermolecular and intra molecular dehydration​

Answers

Intermolecular bonds are the forces between the molecules. Intramolecular are the forces within two atoms in a molecule.

The relation between molarity and normality is expresses as: a) M = N x g.e.w/g.m.w
b) M = N x g.m.w/ g.e.w
c) M = N x no. of equiv./mole
d) M = N x no. of g.m.w/mole

Answers

Answer: [tex]Molarity=Normality\times \frac{gew}{gmw}[/tex]

Explanation:

Molarity is defined as the number of moles dissolved per liter of the solution.

[tex]Molarity=\frac{\text {moles of solute}}{\text {Volume in L}}[/tex]

[tex]{\text {moles of solute}=\frac{\text {given mass}}{\text {Molar mass}}[/tex]  

Normality is defined as the number of gram equivalents dissolved per liter of the solution.

[tex]Normality=\frac{\text {gram equivalents of solute}}{\text {Volume in L}}[/tex]

[tex]{\text {gram equivalents of solute}}=\frac{\text {given mass}}{\text {Equivalent mass}}[/tex]

Thus [tex]Molarity=Normality\times \frac{\text {Equivalent mass}}{\text {Molar mass}}[/tex]

What are primary observations in science?

Answers

Answer:

Observation is the active acquisition of information from a primary source. In living beings, observation employs the senses. In science, observation can also involve the recording of data via the use of scientific instruments. The term may also refer to any data collected during the scientific activity.

Explanation:

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