CORO
Name three ways that scientists can ensure their results
are reliable

Answer:

grond water

Explanation:

Answer:

1.61 mL

Explanation:

Step 1:

Data obtained from the question. This includes the following:

Initial volume (V1) = 1.35 mL

Initial pressure (P1) = 125 kPa

Final pressure (P2) = 105 kPa

Final volume (V2) =..?

Step 2:

Determination of the volume of the air bubble at the surface of the lake.

This can be obtained by use the Boyle's law equation as follow:

P1V1 = P2V2

125 x 1.35 = 105 x V2

Divide both side by 105

V2 = (125 x 1.35)/105

V2 = 1.61 mL

Therefore, the volume of the air bubble at the surface of the lake is 1.61 mL

Answer:

C . A person lifting a weight

Answer:

Both are equal

Explanation:

Mass of starting material i.e Aluminium is [tex]4.480 * 10^{-23}[/tex] grams

The weight of oxygen is [tex]2.65 * 10^{-23}[/tex]

There are 4 atoms of aluminium and 3 atoms of oxygen

Thus, the total mass of starting material is

[tex]4 *[/tex] mass of one atom of aluminium [tex]+ 6 *[/tex] mass of one atom of oxygen

[tex]4 * 4.480 * 10^{-23} + 6* 2.65 * 10^{-23}[/tex]

[tex]35.1 * 10^{-23}[/tex] grams

Mass of new substance is also equal to

[tex]4 *[/tex] mass of one atom of aluminium [tex]+ 6 *[/tex] mass of one atom of oxygen

[tex]4 * 4.480 * 10^{-23} + 6* 2.65 * 10^{-23}[/tex]

[tex]35.1 * 10^{-23}[/tex] grams

Answer:

2.58 L

Explanation:

Please see the step-by-step solution in the picture attached below.

Hope this answer can help you. Have a nice day!

At constant temperature, if the pressure of the gas decreases to the given value, the volume increases to 2.58L.

Boyle's law simply states that "the volume of any given quantity of gas is inversely proportional to its pressure as long as temperature remains constant.

Boyle's law is expressed as;

P₁V₁ = P₂V₂

Where P₁ is Initial Pressure, V₁ is Initial volume, P₂ is Final Pressure and V₂ is Final volume.

Given the data in the question

P₁V₁ = P₂V₂

V₂ = P₁V₁ / P₂

V₂ = ( 1.03atm × 2.45L ) / 0.980atm

V₂ = 2.5235Latm / 0.980atm

V₂ = 2.58L

Therefore, at constant temperature, if the pressure of the gas decreases to the given value, the volume increases to 2.58L.

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Answer: 780 kcal are required to produce 12.00 mol of [tex]Cl_2O_7[/tex]

Explanation:

Endothermic reactions are defined as the reactions in which energy of the product is greater than the energy of the reactants. The total energy is absorbed in the form of heat and written along with reactants.

The balanced chemical reaction is:

[tex]2Cl_2(g)+7O_2(g)+130kcal\rightarrow 2Cl_2O_7(g)[/tex]

According to stoichiometry :

2 moles of [tex]Cl_2O_7[/tex] are produced by absorption of energy = 130 kcal

Thus 12.00 moles of [tex]Cl_2O_7[/tex] are produced by absorption of energy = [tex]\frac{130}{2}\times 12.00=780kcal[/tex]

Thus 780 kcal are required to produce 12.00 mol of [tex]Cl_2O_7[/tex]

Answer:

determining how many ozone molecules are lost in the atmosphere

Pls Mark as Brainliest!!! if this helps...

The mole concept The mole concept can be used to determine the number of ozone molecules are lost in the atmosphere.

The mole concept was introduced by Avogadro. The mole is the SI unit of amount of substance. According to Avogadro, one mole of a substance contains 6.02 × 10^23 atoms, ions, molecules etc.

The mole concept is important in many chemical calculations. The mole concept can be used to determine the number of ozone molecules are lost in the atmosphere. (option C)

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Answer:

5.9 kg  

Explanation:

We must work backwards from the second step to work out the mass of oxygen.

1. Second step

Mᵣ:                                     55.84

            Fe₂O₃ + 3CO  ⟶  2Fe  +  3CO₂

m/kg:                                    7.0

(a) Moles of Fe

[tex]\text{Moles of FeO} = \text{7000 g Fe} \times \dfrac{\text{1 mol Fe}}{\text{55.84 g Fe}} = \text{125 mol Fe}[/tex]

(b) Moles of CO

[tex]\text{Moles of CO} = \text{125 mol Fe} \times \dfrac{\text{3 mol CO}}{\text{2 mol Fe}} = \text{188 mol CO}[/tex]

However, this is the theoretical yield.

The actual yield is 72. %.

We need more CO and Fe₂O₃ to get the theoretical yield of Fe.

(c) Percent yield

[tex]\begin{array}{rcl}\text{Percent yield} &=& \dfrac{\text{ actual yield}}{\text{ theoretical yield}} \times 100 \, \%\\\\ 72. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.72 &= &\dfrac{\text{188 mol}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{188 mol}}{0.72}\\& = & \textbf{261 mol}\\\\\end{array}[/tex]

We must use 261 mol of CO to get 7.0 kg of Fe.

2. First step

Mᵣ:                32.00

            2C   +  O₂   ⟶  2CO

n/mol:                             261

(a) Moles of O₂

[tex]\text{Moles of O}_{2} = \text{261 mol CO} \times \dfrac{\text{1 mol O}_{2}}{\text{2 mol CO}} = \text{131 mol O}_{2}[/tex]

(b) Mass of O₂

[tex]\text{Mass of O}_{2}= \text{131 mol O }_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \text{4180 g O}_{2}[/tex]

However, this is the theoretical yield.

The actual yield is 71. %.

We need more C and O₂ to get the theoretical yield of CO.

(c) Percent yield

[tex]\begin{array}{rcl}71. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.71 &= &\dfrac{\text{4180 g}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{4180 g}}{0.71}\\\\& = & \text{5900 g}\\& = & \textbf{5.9 kg}\\\end{array}[/tex]

We need 5.9 kg of O₂ to produce 7.0 kg of Fe.

Answer:

19.47%

Explanation:

The percentage by mass of [tex]H_2SO_4[/tex] would be 19.47%.

The percentage by mass of a substance in solution is calculated as:

   [tex]\frac{mass of substance}{mass of substance + water} * 100%[/tex]

Given that the mole fraction of [tex]H_2SO_4[/tex] = 0.432

The total number of mole fraction of a solution = 1

Hence, mole fraction of water = 1 - 0.432 = 0.568

Mass of water = molar mass x mole

                              = 98.079 x 0.432 = 42.37 g

Mass of [tex]H_2SO_4[/tex] = molar mass x mole

                          = 18.02 x 0.568 = 10.24 g

Hence,

%mass of [tex]H_2SO_4[/tex] = [tex]\frac{10.24}{10.24 + 42.37} * 100[/tex]

                         = 19.47%

Answer: The answer would be D

Explanation:

The magnitude of the energy change of metal X during the experiment is 6500 J, and the mass of ice melted by metal X is 19.7 g and the claim of the student is correct.

The magnitude of energy change of metal is equal to the mass of metal x specific heat capacity of metal x temp. difference

= 100 g x 0.13 J / ( g- oC) x (500 - 0) oC

= 6500 J

According to the question, the enthalpy of the fusion of ice is 330 J / g

Thus 330 J heat is used to melt 1 g of ice

So 6500 J heat is used to melt = 1 x (6500 / 330) = 19.7 g ice

Although hydrogen bonds can form in both a solid and a liquid state, they are more stronger in the solid state. In order to partially dissolve its hydrogen bonds and turn solid ice into liquid water, whatever heat is applied to it is therefore used.

Therefore, the student's assertion is true.

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Answer:

2.31M

Explanation:

The following data were obtained from the question:

Mole of K2SO4 = 0.450 mole

Volume of water = 195.0 mL = 195/1000 = 0.195L

Molarity =...?

Molarity is defined as the mole of solute per unit litre of the solution. This can be expressed as:

Molarity = mole /Volume

With the above formula we can calculate the molarity of the K2SO4 solution as follow:

Molarity = mole /Volume

Molarity = 0.450/0.195

Molarity = 2.31M

Answer:

The reaction will not occur unless the activation energy is met.

Explanation

Answer:

A. The reaction will not occur unless the activation energy is met.

Explanation:

a.p.e.x

Answer:

The metals have the tedency to lose electrons and become positive ions

Explanation:

In order to attain noble gases electronic configuration, metals of group I A lose one electron and II A lose 2 electrons with ionization energy.

Answer:

i agree with the above to collect rock samples

Explanation:

took test got 100 best of luck

The  purpose of the Apollo space missions was to to collect rock samples from the moon.

The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of Australia).The Moon is a planetary-mass object with a differentiated rocky body, making it a satellite planet under the geophysical definitions of the term and larger than all known dwarf planets of the Solar System.

It lacks any significant atmosphere, hydrosphere, or magnetic field. Its surface gravity is about one-sixth of Earth's at 0.1654 g, with Jupiter's moon Io being the only satellite in the Solar System known to have a higher surface gravity and density.

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Answer:

False

Explanation:

The Strong Nuclear Force is defined as an attractive force between neutrons and protons which is responsible to hold the nucleus together.

Electrostatic force is the repulsive or attractive force between two electrically charged objects.

Strong nuclear force is always greater than electrostatic force but changes with the distance. Strong nuclear attraction keeps the nucleus of an atom together in a small space as well which is stronger  than their electrostatic repulsion.

it is said that, the strong nuclear force is the strongest force in the universe.

Hence, the given statement is false.

Answer:

False

Explanation:

Strong nuclear forces are much higher than the electrostatic repulsive force. In case if these strong nuclear forces would have not been there, then the nucleus would have disintegrated. This is so because only gravity cannot keep hold on these particles. The nuclear force varies with the size of nucleus. As the size of nucleus increases, the electrostatic repulsion becomes greater

Hence, the given statement is false

Answer:

The Eocene Period is experiencing net gain in energy while Cryogenian Period is experiencing a net loss in energy.

Explanation:

In Eocene Period, the population of mammals such as horses , whales and bats etc were high due to the presence of high amount of food and good atmospheric condition such as high temperature while the population of animals were low in Cryogenian Period due to the presence of very low temperature which experiencing loss of energy. Most of area of the earth consist of icy desert.

Answer:

In the roller coasters the potential energy that is given is the gravitational potential energy, which this energy increases its value as the object moves away from the earth, that is to say, the more height the roller coaster acquires the more gravitational potential energy it will have, and Said train where people usually get on the roller coaster will descend or descend with greater acceleration.

This gravitational potential energy once the mountain begins to descend or descend is converted into kinetic energy

Explanation:

This that we wrote above is considering that the roller coaster does not have curved routes but rectilinear, in the case that it had curved routes, a force would be added in addition to those written that is the centripetal force, it is the same force that appears in the centrifuges or dryers of clothes or the same washing machine. This force, the centripetal force is the force that draws a moving object, in a curvilinear path, towards the center of the curvature.

Answer:

1. (i) H₂ will decrease

(ii) H₂ will increase

2. (i) Shift right

(ii) Shift left

(iii) Shift left

(iv) Shift left

3. (i) Shift left

(ii) Shift right

(iii) Shift left

4. (i) H₂O will increase

(ii) H₂O will increase

Explanation:

1. For the reaction, N₂ (g) + 3H₂ (g) ↔ 2NH₃ (g) + 22 kJ

(i) When the NH₃ is removed, the concentration of the products is reduced favoring the consumption of further reactants hence the H₂ will decrease

(ii) When N₂ is removed, N₂ will become the limiting reactant resulting in the presence of excess H₂, hence H₂ will increase

2. 2NO (g) + H₂ (g) ↔ N₂O (g) + H₂O (g) 36 kJ

(i) When NO is added, it will favor the increase of the reaction and the equilibrium will shift to the right

(ii) H₂ is removed, it will favor the decomposition of the products hence the equilibrium will shift to the left

(iii) When N₂O is added, it will cause the increase in the partial pressure of the products which will result in the increase in the partial pressures of the reactants to compensate, hence the equilibrium will shift to the left

(iv) When H₂ is removed it will cause the equilibrium to shift left as more products will decompose to form the balance H₂

3. For the reaction;

CO₂ (g) + H₂ (g) + heat ↔ CO (g) + H₂O (g)

(i) When CO is added, there will be an excess partial pressure of the products and the equilibrium will shift left

(ii) When CO₂ is added, there will be an excess partial pressure of the reactants which will favor the formation of the products and the equilibrium will shift right

(iii) When H₂ is removed, there will be an decrease in the partial pressure and concentration of the reactants which will favor the decomposition of the products to balance up the partial pressures of the reactant and the equilibrium will shift left

4. In the reaction  2NO (g) + H₂ (g) ↔ N₂O (g) + H₂O (g) + heat

(i) When NO is added, the concentration of the reactants will increase, hence increasing the likelihood of the formation of more products and the equilibrium will shift to the right and H₂O will increase

(ii) When N₂O is removed, the partial pressure and concentration of the products will reduce hence to balance up the partial pressures of the reacting mixture, more products will be formed and H₂O will increase.

Answer:

Cut trees at a sustainable rate

and

Plant one tree for every tree that is cut.

hope i helped, if i could get brainliest that would be great

Answer:

Explanation:

Khfxgkfxyfkx

Answer:

28.98°C

Explanation:

Mass = 52g

Initial temperature (T1) = 10°C

Final temperature (T2) = ?

Heat energy (Q) = 4130J

Specific heat capacity of water = 4.184J/g°C

Heat energy (Q) = mc∇T

Q = heat energy

M = mass of the substance

C = specific heat capacity of the substance

∇T = change in temperature (T2 - T1)

Q = mc∇T

4130 = 52 * 4.184 * (T2 - 10)

4130 = 217.568 * ( T2 - 10)

4130 = 217.568T2 - 2175.68

217.568T2 = 4130 + 2175.68

217.57T2 = 6305.68

T2 = 6305.68 / 217.57

T2 = 28.98°C

Final temperature is 28.98°C

Answer:

Matals tend to LOSE electrons to become POSITIVE ions

Answer:

HDHERFEHFFFHRF

Explanation:

Answer:

10moles of NH₃ will produce 660g of (NH₄)₂SO₄

Explanation:

Equation of reaction:

2NH₃ + H₂SO₄ → (NH₄)₂SO₄

2 mole of NH₃ = 1 Mole of (NH₄)₂SO₄

Molar mass of NH₃ = [14 + (3*1)] = 17g/mol

Number of moles = mass / molarmass

Mass = number of mole * molarmass

Mass = 2 * 17 = 34g

Molar mass of (NH₄)₂SO₄ = [(14 + 4)*2 + (32 + 64)

Molar mass of (NH₄)₂SO₄ = 132g/mol

Mass = molar mass * number of moles

Mass = 132 * 1 = 132g

From the equation of reaction,

34g of NH₃ will produce 132g of (NH₄)₂SO₄

34g of NH₃ = 132g of (NH₄)₂SO₄

X g of NH₃ = 660g of (NH₄)₂SO₄

X = (34*660) / 132

X = 170g of NH₃

170g of NH₃ will produce 660g of (NH₄)₂SO₄

Number of moles = mass / molarmass

Molar mass of NH₃ = 17g/mol

Number of moles = 170 / 17

Number of moles = 10moles

Therefore 10moles of NH₃ will produce 660g of (NH₄)₂SO₄

Answer:

It is called catalyst.

Answer:

A catalyst

Explanation:

is a substance that can alter the rate of a chemical reaction. Catalysts can be successfully used to increase the rate of a chemical reaction.

Answer:

I need the things after "which of the following would occur".

Explanation:

If you were to maintain a constant volume while decreasing pressure, the temperature would also have to decrease. This is Boyle's law.