HELPPP PLZZ

During lunch each day, Alex and Hailey have been noticing the trashcans around the lunchroom are filling rather quickly with cans and bottles. They decide a recycling program would be beneficial for their school and the environment, so they brainstorm ways to get the program started. Before discussing their idea with the principal, they need to decide which of their plans would best solve the problem. Which of their ideas would best solve the problem with the least amount of inconvenience (disturbance) for everyone involved? A) Ask volunteers to separate recyclable materials from the trash. B) Remove all vending machines that sell plastic bottles or aluminum cans. C) Get a petition started to build a recycling center close to the school. D) Place plastic and metal recycling bins next to each lunchroom trash can

Answer:

Answer is B

Explanation:

It's not A because we're boiling only water.

It's not C because the last dot for 2 cups ends at 70 min while the last dot for 4 cups ends at 90 min.

It's not D because water boils at around 100 C, as shown in the graph. The highest dot for both 2 cups and 4 cups were about the same near 100 C.

The graph shows that 4 cups of water is able to retain heat more (higher heat capacity), so it takes more time for water to cool down than 2 cups of water.

Answer:

Meter, kilometer & inch - used to measure length or distance.

Answer:

3

Explanation:

Answer:

2)

[tex]\% Mg=20.2\%\\\\\% S=26.6\%\\\\\% O=53.2\%[/tex]

3)

[tex]\% Ag=93.1\%\\\\\% O=6.9\%[/tex]

Explanation:

Hello!

2) In this case, since magnesium sulfate is MgSO₄, we can see how magnesium weights 24.305 g/mol, sulfur 32.06 g/mol and oxygen 64.00 g/mol as there is one atom of magnesium as well as sulfur but four oxygen atoms for a total of g/mol; thus the percent compositions are:

[tex]\% Mg=\frac{24.305}{120.36 } *100\%=20.2\%\\\\\% S=\frac{32.06}{120.36 } *100\%=26.6\%\\\\\% O=\frac{64.00}{120.36 } *100\%=53.2\%[/tex]

3) In this case, although the element seems to contain Ag and O, we infer its molecular formula is Ag₂O; thus, since we have two silver atoms weighing 215.74 g/mol and one oxygen atom weighing 16.00 g/mol for a total of 231.74 g/mol, we obtain the following percent compositions:

[tex]\% Ag=\frac{215.74}{231.74} *100\%=93.1\%\\\\\% O=\frac{16.00}{231.74} *100\%=6.9\%[/tex]

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Answer:

[Fe⁺³] = 0.0010 M

[SCN⁻] = 0.0006 M

Explanation:

First we calculate how many moles of Fe⁺³ and SCN⁻ were added, using the given volumes and concentrations:

Now we can calculate the initial concentrations, after calculating the new volume of the solution:

Answer:

0.64 L

Explanation:

Step 1: Given data

Step 2: Calculate the volume corresponding to 5.4 kg of oil

Density is an intrinsic property and it is equal to the quotient between the mass and the volume.

ρ = m/V

V = m/ρ

V = 5.4 kg/(8.5 kg/L) = 0.64 L

Answer:

21 Kg of CO.

Explanation:

The balanced equation for the reaction is given below:

Fe₂O₃ + 3CO —> 2Fe + 3CO₂

Next, we shall determine the masses of Fe₂O₃ and CO that reacted from the balanced equation. This can be obtained as illustrated below:

Molar mass of Fe₂O₃ = (56×2) + (16×3)

= 112 + 48

= 160 g/mol

Mass of Fe₂O₃ from the balanced equation = 1 × 160 = 160 g

Molar mass of CO = 12 + 16 = 28 g/mol

Mass of CO from the balanced equation = 3 × 28 = 84 g

SUMMARY:

From the balanced equation above,

160 g Fe₂O₃ required 84 g of CO.

Finally, we shall determine the mass of of CO required for the reduction of 40 kg of Fe₂O₃. This can be obtained as follow:

From the balanced equation above,

160 g Fe₂O₃ required 84 g of CO.

Therefore, 40 Kg of Fe₂O₃ will require = (40 kg × 84 g) / 160 g = 21 Kg of CO.

Thus, 21 Kg of CO is required for the reaction.

Answer:

0.0103 mol

Explanation:

Step 1: Given data

Step 2: Convert "m" to grams

We will use the conversion factor 1 g = 1000 mg.

200. mg × 1 g/1000 mg = 0.200 g

Step 3: Calculate the moles (n) of naproxen sodium

We will use the following expression.

n = m/M = 0.200 g / (252 g/mol) = 7.94 × 10⁻⁴ mol

Step 4: Calculate the moles of hydrogen in 7.94 × 10⁻⁴ moles of naproxen sodium

According to the chemical formula, the molar ratio of naproxen sodium to H is 1:13. The moles of H are 13/1 × 7.94 × 10⁻⁴ mol = 0.0103 mol.

Answer:

Explanation:

F=mg

F=35*9.81

F=343.35N

Answer:

its B

Explanation:

The earthquakes are occurring more in the land region of earth surface. Hence, the waves would arrive at point B before they arrived at point.

When two layers of the ground abruptly slide past one another, an earthquake results. The fault or fault plane is the area where they slide. The epicenter is the point on the earth's surface that is directly above the hypocenter, which is where the earthquake begins under the surface.

The energy that would typically force the blocks to move past one another is being saved up while the fault edges are glued together and the rest of the block is moving.

All that accumulated energy is released when the force of the sliding blocks ultimately displaces the resistance of the sharp edges of the fault and causes it to unstick. Like ripples on a pond, the energy radiates from the fracture in all directions as seismic waves. Therefore, point B in the land surface will first experience the seismic waves.

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D. Matter and energy are the same.

Mole measure the number of elementary entities of a given substance that are present in a given sample. Therefore, 8.12×10²³ atoms are in  90.43 mole of copper.

The SI unit of amount of substance in chemistry is mole. The mole is used to measure the quantity of amount of substance. It measure the number of elementary entities of a given substance that are present in a given sample. There are so many formula for calculating mole.

we know one mole of any element contains 6.022×10²³ atoms which is also called Avogadro number

number of atoms/molecules=number of moles × 6.022×10²³(Avogadro number)

number of moles of copper=90.43 moles

Substituting all the given values in the above equation, we get

number of atoms/molecules= 90.43 × 6.022×10²³

number of atoms/molecules=8.12×10²³ molecules

Therefore, 8.12×10²³ atoms are in 90.43 mole of copper.

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Answer:

B) A control group is used for comparison to other groups.

E) A controlled experiment must have a control group and test group(s).

Explanation:

Answer:

B & E should be the answers

Answer:

In 1851 gold-seekers from around the world began pouring into the colonies, changing the course of Australian history. The gold rushes greatly expanded Australia's population, boosted its economy, and led to the emergence of a new national identity.

Explanation:

Answer:

People from all over the world look for gold and in 1851 people started forming colonies to look for it which had a huge impact on the history of Australia.   The gold rushes increased Australia's population which improved its economy.

Answer:

V₂ = 25.065 L

Explanation:

Given data:

Initial volume = 15L

Initial pressure = 1500 mmHg (1500/760 = 1.97 atm)

Initial temperature = 299 K

Final temperature = 350 K

Final volume = ?

Final pressure = 1050 mmHg (1050/760 = 1.38 atm)

Formula:

P₁V₁/T₁ = P₂V₂/T₂  

P₁ = Initial pressure

V₁ = Initial volume

T₁ = Initial temperature

P₂ = Final pressure

V₂ = Final volume

T₂ = Final temperature

Solution:

V₂ = P₁V₁ T₂/ T₁ P₂  

V₂ = 1.97 atm × 15 L × 350 K / 299 K × 1.38 atm

V₂ = 10342.5 atm .L. K / 412.62 K.atm

V₂ = 25.065 L

Answer: The concentration of a benzene solution is 4.05 molal

Explanation:

Molality of a solution is defined as the number of moles of solute dissolved per kg of the solvent.

[tex]Molality=\frac{n\times 1000}{W_s}[/tex]

where,

n = moles of solute

[tex]W_s[/tex] = weight of solvent in g

moles of [tex]C_6H_6[/tex] = [tex]\frac{\text {given mass}}{\text {Molar mass}}=\frac{12.0g}{78g/mol}=0.154mol[/tex]

Now put all the given values in the formula of molality, we get

[tex]molality=\frac{0.154\times 1000}{38.0g}=4.05[/tex]  

Therefore, the concentration of a benzene solution is 4.05 molal

Answer: A> B> C > D> E

Explanation:

pH or pOH is the measure of acidity or alkalinity of a solution.

pH is calculated by taking negative logarithm of hydrogen ion concentration.

[tex]pH=-\log [H^+][/tex]

a) Solution A: pH =2  

[tex][H^+]=10^{-2}[/tex]

b) Solution B: pH =5  

[tex][H^+]=10^{-5}[/tex]

c) Solution C: pH = 7  

[tex][H^+]=10^{-7}[/tex]

d) Solution D: pH = 8  

[tex][H^+]=10^{-8}[/tex]

e) Solution E: pH =13

[tex][H^+]=10^{-13}[/tex]

Thus the decreasing order of hydrogen ion concentration is A> B> C > D> E

the first one is A covalent bond.

the second one is Answer: B Decomposition

Answer and Explanation:

V1/n1 = V2/n2

450.0 mL / 0.0184 mol = 200.0 mL / n2

n2 = 8.17X10^-3 mol

moles removed = 0.0184-8.17X10^-3 = 0.0102 mols removed, I think I'm right but I'm not 100% sure..

According to Avogadro's law, 0.008 moles of gas must be removed to shrink balloon to 200 ml.

Avogadro's law is a gas law which states that the total number of atoms or molecules has a direct proportion to the volume occupied by a gas at a constant temperature and pressure.

It is closely related to ideal gas equation as it links temperature, pressure, volume and the amount of substance.It is given as, V∝n,

The straight line graph of volume versus moles is a straight line passing through the origin which implies that zero moles of gas occupy zero volume.

Here, the number of moles is calculated as, V₁/n₁=V₂/n₂

Therefore on substitution, n₂=0.0184×200/450=0.008 moles.

Thus,0.008 moles are required to shrink  the balloon to 200 ml.

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Answer:

2Fe + 3Cl2 → 2FeCl3

Explanation:

Answer:

2) 0.4 mol

Explanation:

Step 1: Given data

Step 2: Convert "V" to L

We will use the conversion factor 1 L = 1000 mL.

500 mL × 1 L/1000 mL = 0.500 L

Step 3: Calculate the moles of KBr (solute)

The molarity is the quotient between the moles of solute (n) and the liters of solution.

M = n/V

n = M × V

n = 0.8 mol/L × 0.500 L = 0.4 mol

Solution :

For the reaction given :

[tex]$\text{2Hg}_{(l)}+\text{O}_2_{(g)} \rightarrow \text{2HgO}_{(s)}$[/tex]

Thus we know that the equilibrium constant [tex]$K_c$[/tex] contains aqueous an dgas species only.

∴       [tex]$K_c=\frac{1}{[O_2]}$[/tex]    ............(1)

Now at the equilibrium, an amount of the 13.4 g of oxygen was found in the vessel of 6.9 liters. For determining the concentration of the oxygen gas, we use :

[tex]$[O_2]= \frac{n_{O_2}}{V_{soln}}$[/tex]  ...................  (2)

Here, [tex]$n_{O_2}$[/tex] = no. of moles of oxygen gas (mol)

         [tex]$V_{soln}$[/tex] = volume of solution (L)

Therefore the number of moles of the oxygen gas is calculated by directly using the molecular weight (31.9988 g/mol) as the conversion factor.

∴      [tex]$n_{O_2}= 13.4 \ g \times \frac{\text{1 mol}}{31.9988 \ g}$[/tex]

              = 0.418 mol

Now substituting the known values in (2), we can find the equilibrium concentration of the oxygen gas :

[tex]$[O_2] =\frac{0.418 \ \text{mol}}{6.9 \ \text{L}}$[/tex]

     = 0.0605 M

Therefore substituting the result in (1), the equilibrium constant for the reaction is :

[tex]$K_c=\frac{1}{0.0605}$[/tex]

    = 16.52

Answer:

N2O.

Explanation:

Hello there!

In this case, according to the Avogadro's number, we can compute the number of atoms, taking into account that CO2 has three moles of atoms, N2O has three moles of atoms, He one mole of atoms and CO two moles of atoms:

[tex]atoms_{CO_2}=1molCO_2*\frac{3*6.022x10^{23}atoms}{1molCO_2}=1.81x10^{24}atoms\\\\atoms_{N_2O}=3molN_2O*\frac{3*6.022x10^{23}atoms}{1molN_2O}=5.4x10^{24}atoms\\\\atoms_{He}=2molHe*\frac{1*6.022x10^{23}atoms}{1molHe}=1.2x10^{24}atoms\\\\atoms_{CO}=4molCO*\frac{2*6.022x10^{23}atoms}{1molCO}=4.82x10^{24}atoms[/tex]

Thus, we infer that 3 moles of N2O have the greatest number of atoms.

Answer:

stars and lightning. this is the answer ok