Which two forces drive the rock cycle?

A. Weathering and erosion
B. Transportation and deposition
C. Mineral composition of existing rock and time
D. Earth's internal heat engine and the water cycle

Answer:

allows scientists to avoid the effects of light pollution

Explanation:

Space Observatories are instruments such as telescopes that are used for explorations in space.

The main functions of a space observatory is that it helps scientists to be able to view very clear images of objects that are in space such as stars and other planetary bodies.

Space observatories when used on earth , have the tendency to absorb ultraviolet and infrared rays which can be very dangerous to the health of scientists but when these space observatories are used for explorations in space, it's major benefit is that it protects the scientists from light pollution such as ultraviolet radiation and infrared light.

i think A because .10 divided by 40 would be .0025

Answer:

0.0040

Explanation:

Answer:

farther apart and move faster.

Explanation:

Answer:

#11: In a nonpolar covalent bond, electrons are shared equally between two atoms.

#12: Only the diatomic nitrogen molecule [tex]\rm N_2[/tex] contains a triple covalent bond among the four molecules.

Explanation:

Consider: what is a covalent bond?

Two atoms share a pair of electrons (called a bonding pair as opposed to a lone pair) between them.

Nonpolar covalent bonds exist only between atoms with similar electronegativity values. The two bonding atoms attract the bonding pair with similar strength, such that the bonding pair is shared mostly equally between the two atoms.

In case the two atoms differ in their electronegativity, the bonding pair will be closer to the more electronegative atom. That will make a polar covalent bond.

Atoms share electrons with each other to achieve an octet of eight valence electrons (two for hydrogen.) Atoms form a covalent bond for every two valence electrons that they need.

Consider: how many electrons do atoms in each molecule need to gain before achieving an octet?

Fluorine is in group 17 of the new IUPAC periodic table. Each fluorine atom needs 18 - 17 = 1 valence electron to achieve an octet. There are two fluorine atoms in an [tex]\rm F_2[/tex] molecule. These two atoms will need two electrons in total to achieve an octet. They will thus need to form [tex]2/2 = 1[/tex] covalent bond.

Similarly:

Answer:

11.  Electrons are shared equally by two atoms.

12. Diatomic nitrogen

Explanation:

An example of  the  the first  bond is the diatomic hydrogen.

There are 5  electrons in the nitrogen atom's outer shell. The 2 nitrogen atoms will each share 3 electrons to form 3 covalent bonds.

Answer:

11.21 L.

Explanation:

where, P is the pressure of the gas in atm (P = 1.0 atm, Standard P).

V is the volume of the gas in L (V = ??? L).

n is the no. of moles of the gas in mol (n = 0.5 mol).

R  is the general gas constant (R = 0.0821 L.atm/mol.K),

T is the temperature of the gas in K (T = 273 K, Standard T).

∴ V = nRT/P = (0.5 mol)(0.0821 L.atm/mol.K)(273 K)/(1.0 atm) = 11.21 L.

Answer:

BaCo3 (s)

Explanation:

Because it is being formed from two aqueous solutions, and the (s) indicates that it is a solid. Precipitate means "formed into solid". Since BaCo3 is a product, is solid, is formed from two aqueous solutions, it is a precipitate.

Answer:

[tex]\boxed{\text{CH$_{2}$}}[/tex]

Explanation:

1. Calculate the mass of each element

[tex]\text{Mass of C} = \text{2.67 g } \text{CO}_{2}\times \dfrac{\text{12.01 g C}}{\text{44.01 g }\text{CO}_{2}}= \text{0.7286 g C}\\\\\text{Mass of H} = \text{1.10 g }\text{H$_{2}$O}\times \dfrac{\text{2.016 g H}}{\text{18.02 g } \text{{H$_{2}$O}}} = \text{0.1231 g H}[/tex]

2. Calculate the moles of each element

[tex]\text{Moles of C = 0.7286 g C}\times\dfrac{\text{1 mol C}}{\text{12.01 g C }} = \text{0.060 67 mol C}\\\\\text{Moles of H = 0.1231 g H} \times \dfrac{\text{1 mol H}}{\text{1.008 g H}} = \text{0.1221 mol H}[/tex]

3. Calculate the molar ratios

Divide all moles by the smallest number of moles.

[tex]\text{C: } \dfrac{0.06067}{0.06067}= 1\\\\\text{H: } \dfrac{0.1221}{0.06067} = 2.015[/tex]

4. Round the ratios to the nearest integer

C:H = 1:2

5. Write the empirical formula

The empirical formula is [tex]\boxed{\text{CH$_{2}$}}[/tex]

The empirical formula of the compound is CH.

To find the empirical formula of the compound, we need to determine the molar ratios of carbon and hydrogen in the compound based on the masses of carbon dioxide (CO₂) and water (H₂O) produced during combustion.

First, we calculate the moles of carbon in CO₂:

The molar mass of CO₂ is 44.01 g/mol (12.01 g/mol for C and 2 × 16.00 g/mol for O₂).

Moles of CO₂ = 2.67 g / 44.01 g/mol = 0.0607 mol

Since there is one mole of carbon in one mole of CO₂, the moles of carbon are also 0.0607 mol.

 Next, we calculate the moles of hydrogen in H₂O:

The molar mass of H₂O is 18.015 g/mol (2 × 1.008 g/mol for H₂ and 16.00 g/mol for O).

Moles of H₂O = 1.10 g / 18.015 g/mol = 0.0611 mol

The moles of hydrogen:

Moles of H in H₂O = 2 × Moles of H₂O = 2 × 0.0611 mol = 0.1222 mol

Now, let's re-calculate the molar ratio of carbon to hydrogen:

Moles of C / Moles of H = 0.0607 mol / 0.1222 mol = 1/2

This ratio simplifies to:

C: 1

H: 1

Therefore, the correct empirical formula of the compound is CH, not CH₂ as previously stated. The error in the initial calculation has been corrected, and the correct empirical formula is CH.

The oxidation state of a Mn atom in its elemental state is zero. However, in compounds, Mn has multiple potential oxidation states depending on the number of electrons it has lost.

The oxidation state of an atom is typically zero when it is in its elemental state. In the case of a manganese (Mn) atom, this rule applies: the manganese atom has an oxidation state of zero.

However, this can change under certain conditions. For instance, in a chemical reaction, the oxidation state of Mn can vary. Transition metals like Mn usually have multiple oxidation states due to their ability to lose different numbers of d or s orbital electrons.

For example, in a compound such as MnO2, the oxidation state of Mn is +4. Here, Mn has lost four electrons. In another compound such as Mn2+, Mn has lost two electrons, giving it an oxidation state of +2.

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Final answer:

The oxidation state of Mn in the permanganate ion (MnO₄) is +7. This is calculated using the known oxidation state of oxygen (-2) and balancing it with the overall charge of the permanganate ion (-1).

Explanation:

The oxidation state of manganese (Mn) varies depending on the compound it is in. For instance, in the permanganate ion (MnO₄), the oxidation state of Mn is determined using the known oxidation state of oxygen, which is -2. Since there are four oxygen atoms, their combined oxidation state is -8. The permanganate ion itself carries an overall charge of -1, so when adding up the oxidation states of all atoms in the ion, their sum must equal this charge.

The calculation is as follows: Mn + (-2) × 4 = -1, which simplifies to Mn - 8 = -1. Solving for Mn gives us an oxidation state of +7. Therefore, in MnO₄, manganese has an oxidation state of +7. This demonstrates that manganese can have a high oxidation state and act as a strong oxidizing agent.

In other compounds, such as MnO₂ or Mn₂O₇, Mn may have different oxidation states, such as +4 or +7, respectively. The principle is to always include the charge on the atom, and balance the oxidation states with the overall charge of the compound or ion.

Answer:

30m/s

Explanation:

100 / 50 = 2 * 15 = 30m/s

Answer:

[tex]\boxed{\text{10 m/s}}[/tex]

Explanation:

Data:

Cart 1: m₁ = 100 kg; v  =15 m/s

Cart 2: m₂ =  50 kg; v₂ = ?

Calculations:

I assume that the two carts are going at the same speed v₂ after the collision.

[tex]\begin{array}{rcl}\text{Momentum before collision} & = & \text{Momentum after collision} \\\text{100 kg} \times\text{15 m/s} & = &\text{100 kg} \times v_{2} + \text{50 kg} \times v_{2}\\\text{1500 m/s} & = & 100 v_{2} +50 v_{2}\\\text{1500 m/s} & = & 150 v_{2}\\v_{2}& =&\textbf{10 m/s}\\\end{array}\\\\\text{The two carts are now moving at a speed of }\boxed{\textbf{10 m/s}}[/tex]

Answer:

If aluminum is the limiting reactant, NONE of it will still be visible after the reaction completes.

If CuCl2 is the limiting reactant, SOME of the aluminum will still be visible.

Explanation:

So,

If aluminum is the limiting reactant, NONE of it will still be visible after the reaction completes.

and,

If CuCl2 is the limiting reactant, SOME of the aluminum will still be visible.

Answer:

If aluminum is the limiting reactant, none of it will still be visible after the reaction completes.

If CuCl2 is the limiting reactant,  some of the aluminum will still be visible.

Answer:

C

Explanation:

if you heat up a solid - you give it some energy. This causes the particles to move more and the solid to change into a liquid, or melt. If the liquid is heated then it may evaporate and turn into a gas. Taking energy away from a gas (cooling it down) may cause it to turn into a liquid - or condense.

Answer: D. The attractive force between them decreases.

Explanation:

Solid state : It is a state in which the particles are closely packed and does not have any space between them. They have strong intermolecular forces of attraction between them. This state has a definite shape and volume.

Liquid state : It is a state in which the particles are present in random and irregular pattern. The particles are closely arranged but they can move from one place to another.Theintermolecular forces are less as compared to the solids.This state has a definite volume but does not have a fixed shape.

Fusion process is a process where solid state changes to liquid state.The size of particles remain same but the attractive forces between them decrease, thus leading to a random motion of particles.

From the equation,

4 mole of lithium produces 2 mole of lithium oxide

4.37 mol of lithium produces (4.37÷4)x2 mol of lithium oxide

Answer:

D. 86.5 grams

Explanation:

∵ The percentage yield = (actual yield/theoretical yield)*100.

From the balanced reaction:

CaCO₃ + 2HCl → CaCl₂ + CO₂ + H₂O,

It is clear that 1 mol of CaCO₃ reacts with 2 mol of HCl to produce 1 mol of CaCl₂, 1 mol of CO₂, and 1 mol H₂O.

n = mass/molar mass = (95.0 g)/(100.0869 g/mol) = 0.95 mol.

Using cross multiplication:

1 mol of CaCO₃ produce  → 1 mol of CaCl₂, from stichiometry.

∴ 0.95 mol of CaCO₃ produce → 0.95 mol of CaCl₂.

∴ The mass of CaCl₂ (theoretical yield) = (no. of moles) * (molar mass) = (0.95 mol)*(110.98  g/mol) = 105.34 g.

∵ The percentage yield = (actual yield/theoretical yield)*100.

The percentage yield = 82.15%, theoretical yield = 105.34 g.

∴ The actual yield of CaCl₂ = (The percentage yield)(theoretical yield)/100 = (82.15%)(105.34 g)/100 = 86.53 g ≅ 86.5 g.

Answer:

The correct answer is option D.

Explanation:

[tex]CaCO_3 + 2HCl \rightarrow CaCl_2 + CO_2 + H_2O[/tex]

Moles of calcium carbonate = [tex]\frac{95 g}{100.08 g/mol}=0.9492 mol[/tex]

According to reaction,1 mol of calcium carbonate gives 1 mol of calcium chloride.

Then 0.9492 mol of calcium carbonate will give :

[tex]\frac{1}{1}\times 0.9492 mol=0.9492 mol[/tex] of calcium chloride.

Theoretical yield of the calcium chloride = [tex]110.98 g/mol\times 0.9492 mol=105.3422 g[/tex]

Experimental yield of calcium chloride = 95 g

Percentage yield of a calcium chloride = 82.15 %

[tex]\frac{\text{experimental yield}}{\text{Theoretical yield}}\times 100=82.15\%[/tex]

[tex]\frac{\text{experimental yield}}{105.3422 g}\times 100=82.15\%[/tex]

Experimental yield = 86.53 g

The closest option to our answer is option D. Hence, option D is correct answer.

Answer:

Explanation:

Iodine is a halogen so it is the group (column number) 17 of the periodic table. It is a representative element.

The number of valence electrons for the representative elements is equal to the second digit of the group number. So, group 17 means that iodince has 7 valence electrons.

Now, more formally, the valence electrons are the electrons in the outermost shell of the atom and you can determine how many of them an atom has by doing the electron configuration.

These are the steps:

An iodine atom has seven valence electrons and generally gains one electron to become a negatively charged iodide ion (I-). Iodine is in the 17th group of the periodic table and prefers to achieve a full octet by accepting an additional electron rather than losing seven electrons.

An iodine atom has seven valence electrons. When looking to achieve a stable electronic configuration, iodine typically gains one electron to complete its octet because it is more energetically favorable than losing seven electrons. When an iodine atom gains an electron, it forms a negatively charged ion known as an iodide ion (I-). The formula of the resulting ion is I-.

The atomic number of iodine (53) reveals that a neutral atom of iodine consists of 53 protons and an equal number of electrons. Iodine is a halogen and is part of the 17th group in the periodic table which is characteristic of elements with seven valence electrons. According to the octet rule, atoms tend to bond in such a way that they each end up with eight valence electrons; gaining one electron is the preferred pathway for iodine.

The concept of a hypervalent structure involves molecules that contain more than eight electrons in their valence shell. However, in the case of the triiodide ion, resonance structures without violating the octet rule offer a more accurate representation of the bonding. As iodine tends to form weak bonds, the I2 molecule can dissociate into atomic iodine at a relatively lower energy compared to lighter halogens.

Answer:

D

Explanation:

100% on test

The correct answer is: to lend credibility and additional support to their conclusion.

In the excerpt from Levitt and Dubner Freakonomics, the authors are discussing the intersection of morality and economics through the example of a bagel business that operates on an honor system. Despite the predictions of economists that such a system would fail due to rampant theft, the business succeeds because most people choose not to steal even when unsupervised.

The authors then reference Adam Smith's The Theory of Moral Sentiments, where Smith discusses the innate honesty and empathy within humanity.

 The purpose of including the quotation from Adam Smith is not merely to showcase their knowledge of the Scottish philosopher, as this would be more of a display of erudition rather than a contribution to their argument.

Similarly, they are not using the quotation to prove that people are inherently dishonest, as Smith's work actually suggests the opposite that there is an inherent honesty and concern for others in human nature.

The authors also do not use the quotation to argue that incentive is the driving force behind cheating.

While incentives are a significant topic in economics and are discussed in Adam Smith's other major work, The Wealth of Nations, the quotation provided here emphasizes the natural inclination towards honesty rather than the role of incentives in promoting dishonesty.

 Instead, the authors use Smith's quotation to lend credibility and additional support to their conclusion that the honor-system scheme works because of an inherent sense of morality in most people.

By invoking a respected economist and moral philosopher who argued for the existence of moral principles that guide human behavior, even when there is no direct benefit to oneself, Levitt and Dubner strengthen their argument that moral behavior can prevail in economic transactions, contrary to what might be expected based on pure economic self-interest.

Adam Smith's authority in both economics and moral philosophy makes his perspective particularly relevant and persuasive in supporting the authors' observations about human behavior in the context of the bagel business.

Answer:

2RbNO₃ + BeF₂ → Be(NO₃)₂ + 2RbF, because Be keeps a 2+ charge throughout the reaction.

Explanation:

2RbNO₃ + BeF₂ → Be(NO₃)₂ + 2RbF, because Be keeps a 2+ charge throughout the reaction.

Answer:

b

Explanation:

Answer:

In the electrolysis of brine, the substances produced at the cathode are sodium metal and hydrogen gas.

Explanation:

In the electrolysis of brine (Sodium chloride solution) using carbon as electrode, Chlorine gas is produced in the positive electrode (anode), while hydrogen gas is produced in the negative electrode (cathode).

Again, in the electrolysis of molten sodium chloride, chlorine gas is produced in anode, while sodium metal is produced in the cathode.

Nacl ⇄ Na⁺ + Cl⁻

Case 1: Molten Nacl

Anode(+ve) Product                              |    Cathode (-ve) product  

Cl⁻ -----> Cl + e⁻                                      |   Na⁺ + e⁻ ---------> Na

Cl + Cl ------> Cl₂

Case 2: Nacl solution

Anode(+ve) Product                              |    Cathode (-ve) Product

Cl⁻ -----> Cl + e⁻                                      |   H⁺ + e⁻ ---------> H

Cl + Cl ------> Cl₂                                     |   H + H ------------> H₂

Thus, cathodic products of electrolysis of brine are sodium metal and hydrogen gas                                

Answer:

fossil fuel combustion

Explanation:

Fossil fuel is the source of energy that drives almost all industrial processes on the surface of earth. Burning of these fuels releases energy for use in automobiles, industries, homes e.t.c. The complete combustion of these fuels in the presence of oxygen liberates carbon-dioxide and water with heat energy.

Fossil fuels are to a large extent hydrocarbon compounds and their derivatives. They form from organisms million of years ago. When organic matter is prevented from decay in an oxic or oxygen rich environment, they are able to conserve and preserve the energy in them for a vast duration in geologic time. This preserved energy is what becomes available during combustion.

Some of the fossil fuels are oil, natural gas, coal, e.t.c.

Answer: If it has a 1/2 life of 14 days, after 14 days there will be half of it left correct?  

Explanation:So, how many half-lifes are in 42 days?  

42 / 14 = 3  

This means it will divide 3 times.  

1st half life period: 10 / 2 = 5g  

2nd period: 5 / 2 = 2.5g  

3rd period: 2.5 / 2 = 1.25g

10 g at start, 5 g at 14 days, 2.5 g at 28 days, 1.25 g at 42 days.

Answer: The amount of substance left will be 0.316 grams.

Explanation:

All the decay processes follow first order kinetics.

The equation used to calculate half life for first order kinetics:

[tex]t_{1/2}=\frac{0.693}{k}[/tex]

where,

[tex]t_{1/2}[/tex] = half life of the reaction = 14 days

k = ?

Putting values in above equation, we get:

[tex]k=\frac{0.693}{14days}=0.0495days^{-1}[/tex]

Rate law expression for first order kinetics is given by the equation:

[tex]t=\frac{2.303}{k}\log\frac{a}{y}[/tex]

where,

k = rate constant  = [tex]0.0495days^{-1}[/tex]

t = time taken for decay process = 70 days

a = initial amount of the reactant  = 10 grams

y = amount left after decay process  = ? grams

Putting values in above equation, we get:

[tex]70days=\frac{2.303}{0.0495days^{-1}}\log\frac{10g}{y}\\\\y=0.316g[/tex]

Hence, the amount of substance left will be 0.316 grams.

Answer: a) 3

On the right side of the equation you have 6F, so you need 3 copies of F2 to balance the equation.

Answer:

a) 3

Explanation:

The unbalanced combustion reaction is shown below as:-

[tex]N_2+F_2\rightarrow 2NF_3[/tex]

On the left hand side,  

There are 2 nitrogen atoms and 2 fluorine atoms

On the right hand side,  

There are 2 nitrogen atoms and 6 fluorine atoms

Nitrogen atoms are balanced and only fluorine atoms have to be balanced by applying a stoichiometric coefficient of 3 in from of [tex]F_2[/tex] in the reactant side.

Thus, the balanced reaction is:-

[tex]N_2+3F_2\rightarrow 2NF_3[/tex]

Coefficient in front of the [tex]F_2[/tex] in the balanced equation - 3

Answer:

Explanation:

The notation of the most common isotope of silicon is:

The superscript, 28, to the left of the chemical symbol, Si, is the mass number, usually identified with the symbol A, and it is the sum of the protons and neutrons.

The subscript, 14, to the left of the chemical symbolr, Si, is the atomic number, Z, which is the number of protons.

Then, you have this equation:

The number of protons is the same for any isotope of the same element. This is, all the isotopic forms of silicon have the same number of prtons: 14

The number of neutrons is determined from the equation A = Z + N, solving for N:

Hence, the most common isotope of silicon has 14 protons and 14 neutrons.

Answer:

Hydrogen ions

Explanation:

Acidic solutions have high concentrations of hydronium ions and a lower concentration of hydroxide ions. The concentration of hydronium ions determines the acidity of the solution.

Acidic solutions have high concentrations of hydronium ions (H+) and a proportionally lower concentration of hydroxide ions (OH-). This is due to the ionization of the acid, which releases H+ ions into the solution. The concentration of hydronium ions is a critical determinant of the solution's acidity.

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The answer is in the photo.

Answer:

add 7.5L of water

Explanation:

M1×V1=M2×V2

M is molarity, V is volume

0.7 × 10 = 0.4 × V2

V2= 17.5L

vol. of water to add= 17.5 - 10 = 7.5L

The volume which is required to prepare 0.4M lemonade is 17.5L.

Required volume of the solution will be calculated by using the below equation as:

M₁V₁ = M₂V₂, where

M₁ & V₁ are the molarity and volume of initial lemonade.

M₂ & V₂ are the molarity and volume of final prepared lemonade.

On putting all values from the question, we get

V₂ = (0.7)(10) / (0.4) = 17.5 L

Hence required volume of final lemonade is 17.5 L.

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Answer:

a. endothermic

Explanation:

So, Any reaction that absorbs 150 kcal of energy can be classified as a. endothermic.

Final answer:

The molarity of sulfuric acid when titrated with potassium hydroxide, given the volumes and molarity of KOH used, is calculated to be 0.200 M, option C.

Explanation:

To find the molarity of sulfuric acid (H₂SO₄) when titrated with potassium hydroxide (KOH), we use the equation for the reaction:

H₂SO₄ (aq) + 2KOH(aq) → K₂SO₄ (aq) + 2H₂O (l)

Note that the stoichiometry requires 2 moles of KOH to neutralize 1 mole of H₂SO₄. Given that 50.0 mL of 0.200 M KOH is used, we can calculate the moles of KOH used:

Since it takes 2 moles of KOH to neutralize 1 mole of H₂SO₄, the moles of H₂SO₄ neutralized will be half that of KOH used:

Finally, to find the molarity of H₂SO₄ in the 25.0 mL sample:

Therefore, the molarity of the sulfuric acid is 0.200 M, which corresponds to option C.

Answer:

Explanation:

1) Definition of mole fraction: number of moles of a component / number of moles total number of moles.

2) The number of moles of each component is determined from the respective molar mass. Using the letter n for the number of moles of a component:  

3)      CH₄O

        Molar mass CH₄O = 32.04 g/mol

        n₁ = mass CH₄O / 32.04 g/mol

4)  C₂H₆O

        Molar mass C₂H₆O = 46.07 g/mol

        n₂ = C₂H₆O = mass of C₂H₆O / 46.07 g/mol

5) Both masses are equal; call them m.

6) Mole fraction of CH₄O:

Use the letter X for mole fraction.

Cancel the common factor m:

        X₁ =  [ 1 / 32.04] / [1 / 32.04 + 1 /46.07] = 0.590

7) Mole fraction of C₂H₆O

The mole fractions are rounded to three significant figures.

Answer:

if in excess the carbon dioxide is harmful to both the humen and other living things.

Explanation:

in our daily life we exhale carbon dioxide after inhaling oxygen.

but if carbon dioxide is in excess  in atmosphere which is caused by burning fossils may cause changes in weather and climate at large due to aerosol particle emittion which inturn cause damage to o-zone layer causing global warming.which are effect to aquatic life and also to human.

Answer:

They have a definite volume

Explanation:

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Answer: Option (c) is the correct answer.

Explanation:

In solids, particles are held together by strong intermolecular forces of attraction between them. Due to this reason solids acquire a definite shape and volume.

Whereas in liquids, particles are held by less strong intermolecular forces of attraction. As a result, molecules are able to slide past each other. Liquids acquire the shape and volume of a container in which they are kept.

Hence, liquids also show fixed volume.

Thus, we can conclude that property shared by solids and liquids is that they have a definite volume.

Answer:   D.  400

Explanation:  The given image of the graph explains the relation between the pressure and the temperature of the substance.

Through this graph, one can find the approximate vapor pressure at any phase of the substance.

Thus as we can observe from the graph that the  the approximate vapor pressure when the gas condenses at 80°C is 400.