During a lunar eclipse, the moon appears to be darkened because _______________ is casting a shadow on it.

the earth
the sun
Mars

Answer:

density

Explanation

Kilometer - km - 1,000

Hectameter - hm - 100

Decameter - dam - 10

Millimeter - mm - 0.001

The table provides clear prefix rules.

The prefixes can be used for most (if not all) units such as grams (kg,mg...).

Hello there i hope you are having a good day :) Answer :

Prefix with the base unit meter :   Symbol :        Number of meters  :

. (kilometre)                                       (Km)              =   1000 m

. (Hectometre)                                   (HM)             =   100 m

. (Decameter)                                    (Dam)            =   10 meters

. (Millimetre)                                       (mm)             =   0.001 meters

Hopefully this help you :)

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Your answer is In Image Provided.

Answer:

Explanation:

In a simple pendulum with no friction, mechanical energy is conserved.  Total mechanical energy is a combination of kinetic energy and gravitational potential energy.   As the pendulum swings back and forth, there is a constant exchange between kinetic energy and gravitational potential energy

Answer: combining rubber with sulphur

Explanation:

Chemical change is the change in which chemical composition of the substance changes by rearrangement of atoms.

Physical change is a change in which only the physical properties such as size, shape etc change and there is no rearrangement of atoms.

1. Deflating a rubber balloon only decreases the size of balloon and hence is a physical change.

2. Combining rubber with sulphur is vulcanisation in which sulphur forms bonds with rubber and thus is a chemical change.

3. Stretching an elastic rubber band only changes the shape and hence is a physical change.

4. Erasing pencil marks from a page does not involve any rearrangement of atoms and thus is a physical change.

Answer:

Instrinsic Solubility, Temperature, and Sample Size.

Answer:

Explanation:

From Einstein's postulate, mass can be converted to energy using the expression below:

         E = mc²

E is energy, m is the mass and c is the speed of light.

In a nuclear fusion process; 4 hydrogen atoms with a mass of 1.00794 combines to produce an helium atom of mass 4.0026. There is a mass difference between the 4 fusing hydrogen atoms and the resulting Helium atom:

   Mass difference = 4(mass of hydrogen) - mass of helium

   Mass difference = 4(1.00794 ) - 4.0026 = 4.03176 -  4.0026 = 0.02916

It is this difference in mass that is converted to energy that powers the sun.

Final answer:

The slight mass difference between four hydrogen atoms and one helium atom, through the process of nuclear fusion, is converted into a significant amount of energy, powering the sun's radiation and 'shine'.

Explanation:

The difference in the mass of four hydrogen atoms and one helium atom explains the energy released by the sun through the process of nuclear fusion. In nuclear fusion, four hydrogen nuclei (4 H) combine to form one helium nucleus (He), and this process results in a slight loss of mass. This mass is not lost but converted into energy according to Einstein's equation, E=mc2, where E is energy, m is mass, and c is the speed of light. The mass difference, although small (—0.7% less for helium compared to the combined mass of four hydrogen atoms), gets converted into a vast amount of energy. Specifically, this reaction produces about 3.6 × 1011 kJ of energy per mole of He produced. This energy is what causes the sun to 'shine' and radiate energy throughout the solar system.

Answer:

0.048M

Explanation:

Volume of acid = 25mL = 0.025L

Concentration of base NaOH = 0.12M

Volume of base NaOH = 10mL= 0.01L

Unknown:

concentration or molarity of the nitric acid = ?

Solution

We first write the balanced reaction equation:

           HNO₃ + NaOH → NaNO₃ + H₂O

In this problem, the focus is on the reacting acid and base which are on the left hand side.

Now, to find the molarity of the nitric acid that would be completely neutralized by the base, we adopt the mole concept.

First, we work from the known to the unknow. We can find the number of moles of the base given because its parameters are complete. The number of moles is given by the expression below:

        Number of moles = concentration x volume

To find the number of moles of the base, we put the parameters into the expression above:

Number of moles of NaOH = concentration of NaOH x volume of NaOH

                                              = 0.01 x0.12

                                              = 0.0012mol

From the number of moles of the base, we can find the unknown.

  In the reaction equation:

      1 mole of base neutralizes 1 mole of the acid

      0.0012mole of the base will neutralize 0.0012mole of the acid

Therefore, 0.0012mole of HNO₃ was neutralized.

Now we can calculate the molarity of the acid using the expression below:

     concentration of acid = [tex]\frac{ number of moles of acid}{volume of acid}[/tex]

     concentration of acid = [tex]\frac{0.0012 }{0.025}[/tex] = 0.048M

The molarity of nitric acid (HNO3) used in the titration with 0.12 M NaOH is 0.048 M, calculated using the moles of NaOH needed to neutralize the acid and the volume of HNO3.

Given that the NaOH base has a concentration of 0.12 M and a volume of 10.0 mL was used to neutralize the acid, we first convert the volume of NaOH to liters (10.0 mL = 0.010 L) to calculate the moles of NaOH:

Moles of NaOH = Molarity × Volume (in liters) = 0.12 M × 0.010 L = 0.0012 mol

Since the reaction between HNO3 and NaOH is 1:1, the moles of HNO3 are equal to the moles of NaOH. Using the volume of HNO3 (25.0 mL = 0.025 L), we can calculate its molarity:

Molarity of HNO3 = Moles of HNO3 / Volume of HNO3 in liters = 0.0012 mol / 0.025 L = 0.048 M

CO+2 H2=CH3OH

2.85 mol Co x (2mol H2/1 mol Co)=5.70 mol just concert to grams

5.70 mol H2 x (2 g H2/1 mol H2) =11.40 grams of H2

To react with 2.85 moles of CO, 11.4912 grams of hydrogen gas (H₂) are necessary based on the balanced equation 2 H₂ + CO → CH₃OH.

To determine how many grams of hydrogen are necessary to react with 2.85 mol of CO, we need to refer to the balanced chemical reaction equation that hydrogen and CO might participate in. One such reaction is the synthesis of methanol:

2 H₂ + CO → CH₃OH

According to this equation, 2 moles of hydrogen gas (H₂) react with 1 mole of carbon monoxide (CO) to produce methanol (CH₃OH). Therefore, to react with 2.85 moles of CO, we would need 5.70 moles of hydrogen gas (2 x 2.85 moles of CO). To convert moles of hydrogen to grams, we multiply by the molar mass of hydrogen (approximately 2.016 g/mol for H₂).

5.70 moles H₂ x 2.016 g/mol = 11.4912 g of H₂

Thus, 11.4912 grams of hydrogen are necessary to react with 2.85 moles of CO.

Answer:

from 2-pentanone  chloropentane  pentene  and pentane, the correct one is 2-pentanone .

Answer:

The reaction will continue in the forward direction until all the NO or all the NO₂ is used up.

Explanation:

Answer:

D

Explanation:

Answer:

A metallic bond

Explanation:

Answer:

True

Explanation:

There are four time zones in the continental United States: Eastern, Central, Mountain and Pacific.

There are four time zones in the continental United States. Hence, option A is correct.

A continent is a large continuous mass of land conventionally regarded as a collective region.

There are actually six time zones in the USA.

The four main ones are Eastern, Central, Mountain, and Pacific Standard Time.

Hence, option A is correct.

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Answer:

A. 1

Explanation:

The higher you get in the atmosphere the cooler the temperature will be. The reason it's actually colder is because, as you go up in the atmosphere, the Earth's atmosphere feels less pressure the higher up you go. So as the gas in the atmosphere rises it feels less pressure, which makes it expand.

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Answer:

The first one is right :)

Explanation:

I got it right on Plato.

The molarity of both solutions is the same, equaling to approximately 1.0 M (mol/L), because molarity is determined by the number of moles of solute per liter of solution, not just the solvent.

Yes, the molarity of both solutions would indeed be the same. Molarity is defined as the number of moles of solute per liter of solution. In your first solution, you dissolved 1.0 moles of NaCl in a total of 1.0 liter of solution. In your second situation, you added 1.0 moles of NaCl to 1.0 liters of water, assuming it does not change the volume substantially, the total volume of the solution is also about 1.0 liters. Thus, the molarity, in both cases, would be approximately 1.0 M (mol/L). It's important to remember that molarity takes into consideration the entire volume of the solution, not just the solvent.

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While both solutions have the same amount of sodium chloride, the process of preparation leads to different volumes of the final solution which influences the molarity. Thus, the molarities of the two solutions are different with the first one being more concentrated.

The molarity of a solution is calculated by dividing the number of moles of solute by the volume of the solution in liters.

In the first solution, 1.0 mole of sodium chloride (NaCl) is dissolved to make 1.0 liters of solution, hence its molarity is 1.0 moles/liter.

In the second solution, 1.0 moles of NaCl is added to 1.0 liters of water; however, when sodium chloride is added, the volume of the solution increases, so the resulting volume of the solution is greater than 1.0 liter which ultimately lessens the molarity of the solution.

Therefore, the molarity of the first solution is greater than the molarity of the second solution despite having the same amount of sodium chloride.

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Answer:

Gravity and Mass.

Explanation:

The Earth has more mass than the moon and therefore a higher force of gravity. Because the Earth has a higher mass and force of gravity the moon is attracted to it.

Answer:

The positions of the planets at the time of birth have influence on a person's life

the niche of an organism is largely based on the evolution of an organism's physiology, behavior, and morphology

The mass of [tex]\( \text{Al}_2\text{O}_3 \)[/tex] produced is approximately [tex]\( 709 \text{ g} \).[/tex]

To determine the mass of [tex]\( \text{Al}_2\text{O}_3 \)[/tex] produced when 375 grams of [tex]\( \text{Al} \)[/tex] react completely, follow these steps:

Given Reaction:

[tex]\[ 4 \text{Al} + 3 \text{O}_2 \rightarrow 2 \text{Al}_2\text{O}_3 \][/tex]

Steps:

1. Calculate the molar mass of [tex]\( \text{Al} \) and \( \text{Al}_2\text{O}_3 \):[/tex]

Molar mass of Al aluminum: [tex]\( 26.98 \text{ g/mol} \)[/tex]

Molar mass of [tex]\( \text{Al}_2\text{O}_3 \)[/tex] aluminum oxide:

[tex]\[\text{Molar mass of } \text{Al}_2\text{O}_3 = (2 \times 26.98 \text{ g/mol}) + (3 \times 16.00 \text{ g/mol}) = 53.96 \text{ g/mol} + 48.00 \text{ g/mol} = 101.96 \text{ g/mol}\][/tex]

2. Convert the mass of [tex]\( \text{Al} \)[/tex] to moles:

[tex]\[\text{Moles of Al} = \frac{\text{mass of Al}}{\text{molar mass of Al}} = \frac{375 \text{ g}}{26.98 \text{ g/mol}} \approx 13.91 \text{ mol}\][/tex]

3. Use the stoichiometry of the reaction to find the moles of [tex]\( \text{Al}_2\text{O}_3 \)[/tex] produced:

According to the balanced equation, 4 moles of Al produce 2 moles of[tex]\( \text{Al}_2\text{O}_3 \)[/tex]. So:

[tex]\[\text{Moles of } \text{Al}_2\text{O}_3 = \left(\frac{2 \text{ moles } \text{Al}_2\text{O}_3}{4 \text{ moles Al}}\right) \times 13.91 \text{ mol} = 6.95 \text{ mol}\][/tex]

4. Convert the moles of [tex]\( \text{Al}_2\text{O}_3 \)[/tex] to grams:

[tex]\[\text{Mass of } \text{Al}_2\text{O}_3 = \text{moles of } \text{Al}_2\text{O}_3 \times \text{molar mass of } \text{Al}_2\text{O}_3\][/tex]

[tex]\[\text{Mass of } \text{Al}_2\text{O}_3 = 6.95 \text{ mol} \times 101.96 \text{ g/mol} \approx 708.7 \text{ g}\][/tex]

Answer: C. Secondary data

Explanation:

It means that the data that was collected by someone else that is not the scientist, it may include censuses, surveys, data bases or other sort of information. Such data could be collected by different private companies, from organizational records to government departments, as they often collect data for other research purposes and the information is available to be used for other scientific purposes.

A data that is not directly collected or observed by the scientist is called: C. Secondary data.

Data can be defined as a representation of instructions or factual information in a formalized manner, especially as a series of binary digits (bits) or samples that are used by scientist in an experiment or research.

Generally, there are two (2) main types of data and these include:

In Science, a secondary data refers to a type of data that isn't directly collected or observed by the scientist but from a primary source.

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Answer: Accepted Theory

Explanation: A scientific theory is an explanation of an aspect of the natural world that can be repeatedly tested and verified in accordance with the scientific method, using accepted protocols of observation, measurement, and evaluation of results. Where possible, theories are tested under controlled conditions in an experiment.

Answer:

B. Nonpolar covalent bond

Explanation:

Between two Nitrogen atoms, a non-polar covalent bond would be formed.

So, what is the nature of a covalent bond, and what makes a covalent bond non-polar?

A covalent bond is a type of bond that forms between two atoms that shares their valence electrons. The valence electrons are donated by the two atoms and they are shared in order to achieve an octet. This bond type is predominantly between atoms that have an electronegativity difference less than 0.5. Using the electronegativity values, we see that a difference of 0 would be obtained.

Due to equal affinities of the two atoms for the valence electrons, none of them will pull the electrons closer to themselves. There won't be any form of charge separation on the two atoms and a Nitrogen molecule will form. This makes the bond type a non-polar covalent type.

Answer:

B. Nonpolar covalent bond

Explanation:

Between two Nitrogen atoms, a non-polar covalent bond would be formed.

So, what is the nature of a covalent bond, and what makes a covalent bond non-polar?

A covalent bond is a type of bond that forms between two atoms that shares their valence electrons. The valence electrons are donated by the two atoms and they are shared in order to achieve an octet. This bond type is predominantly between atoms that have an electronegativity difference less than 0.5. Using the electronegativity values, we see that a difference of 0 would be obtained.

Due to equal affinities of the two atoms for the valence electrons, none of them will pull the electrons closer to themselves. There won't be any form of charge separation on the two atoms and a Nitrogen molecule will form. This makes the bond type a non-polar covalent type.

Answer:

A very large amount of energy is produced from a very small mass

Explanation:

Nuclear energy is produced either by fusion or fission. The former is the fusion of lighter atoms into heavier elements while the latter is the splitting of a heavier atom into lighter atoms. Both produce tremendous amounts of energy. Fusion, causes compaction of mass while fission reduces it. Fusion does not produce radioactive particles while fission does (alpha and beta particles and neutrons).

Energy changes during nuclear fission involve the conversion of a very small amount of mass into a large amount of energy, much more than is produced in chemical reactions like burning coal.

Nuclear fission is a process where the nucleus of an atom, typically a heavy element like uranium-235, is split into smaller, lighter nuclei. The correct description of energy changes during nuclear fission is: a very large amount of energy is produced from a very small mass. This is due to the relationship between mass and energy as described by Einstein's mass-energy equivalence formula, E=mc2. When a mole of uranium-235 undergoes fission, there is a small decrease in the total mass of the products compared to the original mass (about 0.2 grams). According to the formula, this 'lost' mass is converted into a vast amount of energy, approximately 1.8 × 1010 kJ per mole. This energy release in nuclear fission reactions far exceeds the energy produced in chemical reactions, such as the burning of coal.

Answer:

3.07 × 10^4=30,700

3.07 × 10^-4=0.000307

3.07 × 10^-6=0.00000307

3.07 × 10^6=3,070,000

Explanation:

Answer:

Explanation:

Scientific notation: It is the representation of expressing the numbers which are too big or too small by representing them in decimal form with one digit before the decimal point times 10 raise to the power.

For example : 6,000,000 is written as [tex]6.0\times 10^6[/tex]

Answer:

32 mols of water

Explanation:

2H2 + O2 ==> 2H2O

What your givens are telling you and what the equation is saying is that

for every mol of O2, you get 2 mols of H2O

So you could do it with the proportion about.

1/16 = 2/x                 Cross multiply

x = 16 * 2

x = 32

Answer:

32 mol

Explanation:

The balanced reaction from Oxygen and Hydrogen to form Water is:

(1/2)O₂ + H₂ ⇒ H₂O

So, 1/2 mol of oxygen forms 1 mol of water. The stoichiometry calculus must be:

1/2 mol of O₂ -------------------------- 1 mol of H₂O

16 mol of O₂ --------------------------- x mol of H₂O

By a direct simple three rule:

(1/2)x = 16

x = 32 mol

Answer:

- 386.6 kJ/mol.

Explanation:

ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants)

∴ ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants) = [ΔHf(Ca(OH)₂(s)) + ΔHf(H₂)(g)] - [ΔHf(Ca)(s) + 2*ΔHf(H₂O)(l)].

ΔHf(Ca(OH)₂(s)) = - 985.2 kJ/mol, ΔHf(H₂)(g) = 0.0 kJ/mol, ΔHf(Ca)(s) = 0.0 kJ/mol, ΔHf(H₂O)(l) = - 285.8 kJ/mol.

∴ ΔHrxn = ΣΔHf(products) - ΣΔHf(reactants) = [ΔHf(Ca(OH)₂(s)) + ΔHf(H₂)(g)] - [ΔHf(Ca)(s) + 2*ΔHf(H₂O)(l)] = [(- 985.2 kJ/mol) + (0.0 kJ/mol)] - [(0.0 kJ/mol) + 2*(- 285.8 kJ/mol)] = - 386.6 kJ/mol.

Answer:

.18 M

Explanation:

1st

The molarity of an aqueous solution (a solution that has water as the solvent) can be found just by remember this one formula = [tex]\frac{mol}{liters}[/tex].

[moles of solute / volume of solution in L]

So, what do we have? From a glance we have the number of solute (Potassium Chromate), that tells us that we need to convert that value that is in grams (g) into...Moles or (mol), we can do that like this

[tex]\frac{3.50 g}{ } \frac{1 mol}{194.19 g}[/tex]

After we cross multiply 3.50 times 1 and then divide by 194.19 - we get this value ⇒ .018 mol (the g cancels, and we keep mol)

(We get the 194.19 from adding up the molecular weight of Potassium Chromate, which is about 194.19 g/mol. In the above equation though, we flipped this, so that 1 mol is in the numerator and the 194.19 is in the denominator; this helps us convert the 3.50 g to moles).

2nd

Now, we just have to remember that 1 liter = 1000 ml. Because its easier for us to use a L instead of "ml" in the molarity formula. So...

100.00 ml = .1 L         ....

(because [tex]\frac{100 ml}{ } \frac{1 L}{1000 ml} = .1L[/tex]

Finally, we just add our (.018 mol and .1 L) into one nice equation (plug the numbers we converted to back in)

[tex]\frac{.018 mol}{.1L} = .18 M[/tex]

Is it clear now?