ONE ANSWER
Which statement describes an effect of large asteroid and comet impacts?
They may cause continents to move.
O They may cause small craters on Earth's surface.
O They may cause changes limited to within the crater,
O They may kick up dust and pollute Earth's atmosphere.

Answer:

11.31g NaClO₂

Explanation:

Is given 250mL of a 1.60M chlorous acid HClO2 solution. Ka is 1.110x10⁻². What mass of NaClO₂ should the student dissolve in the HClO2 solution to turn it into a buffer with pH =1.45?

It is possible to answer this question using Henderson-Hasselbalch equation:

pH = pKa + log₁₀ [A⁻] / [HA]

Where pKa is -log Ka = 1.9547; [A⁻] is the concentration of the conjugate base (NaClO₂), [HA] the concentration of the weak acid

You can change the concentration of the substance if you write the moles of the substances:

[Moles HClO₂] = 250mL = 0.25L×(1.60mol /L) = 0.40 moles HClO₂

Replacing in H-H expression, as the pH you want is 1.45:

1.45 = 1.9547 + log₁₀ [Moles NaClO₂] / [0.40 moles HClO₂]

-0.5047 = log₁₀ [Moles NaClO₂] / [0.40 moles HClO₂]

0.3128 = [Moles NaClO₂] / [0.40 moles HClO₂]

0.1251 = Moles NaClO₂

As molar mass of NaClO₂ is 90.44g/mol, mass of 0.1251 moles of NaClO₂ is:

0.1251 moles NaClO₂ ₓ (90.44g / mol) =

Answer:

2 CH₃OH  +  3 O₂  ⇒  2 CO₂  +  4 H₂O

Explanation:

Methanol is CH₃OH.  Oxygen is O₂.  A combustion produces CO₂ and H₂O.  Create an equation using this information and balance.

CH₃OH  +  O₂  ⇒  CO₂  +  H₂O

2 CH₃OH  +  3 O₂  ⇒  2 CO₂  +  4 H₂O

The balanced equation for the combustion of liquid methanol in air, assuming H2O(g) as a product is

CH₃OH(l) + O₂(g) → CO₂(g) + H₂O(g)

From the question,

We are to write a balanced equation for the combustion of liquid methanol in air.

The combustion of liquid methanol in air is the reaction between methanol (CH₃OH) and oxygen (O₂). The reaction yields carbon(IV) oxide and water.

Now, for the balanced equation for the combustion of liquid methanol in air

The balanced chemical equation is

CH₃OH(l) + O₂(g) → CO₂(g) + H₂O(g)

Hence, the balanced equation for the combustion of liquid methanol in air, assuming H2O(g) as a product is CH₃OH(l) + O₂(g) → CO₂(g) + H₂O(g)

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Answer:

2 PbS(s) + 1.5 O₂(g) + PbO(s) ⇒ 2 SO₂(g) + 3 Pb(s)

Explanation:

Lead can be prepared from galena [lead(II) sulfide] by first heating with oxygen to form lead(II) oxide and sulfur dioxide. The corresponding chemical equation is:

PbS(s) + 1.5 O₂(g) ⇒ PbO(s) + SO₂(g)

Heating the metal oxide with more galena forms the metal and more sulfur dioxide. The corresponding chemical equation is:

2 PbO(s) + PbS(s) ⇒ 3 Pb(s) + SO₂(g)

We can get the overall reaction by adding both steps and canceling what is repeated on both sides.

2 PbS(s) + 1.5 O₂(g) + 2 PbO(s) ⇒ PbO(s) + 2 SO₂(g) + 3 Pb(s)

2 PbS(s) + 1.5 O₂(g) + PbO(s) ⇒ 2 SO₂(g) + 3 Pb(s)

Answer:

Oxygen

Explanation:

First, list out all the ions in the aqueous solution:

Ag+, NO3-

H+, OH-

In the anode, the substance lose electrons to undergo oxidation.

From the 4 ions, only OH- can lose electrons to form water and oxygen,

4OH- --->  O2 + 2H2O + 4e-

While others tend to gain electrons to form new substances instead (they undergo reduction).

Oxygen is the gas produced.

The gas should be treated as the Oxygen.

here First, list out all the ions that should be in the aqueous solution:

Ag+, NO3-

H+, OH-

In the anode, the substance loses electrons for undergoing oxidation.

From the 4 ions, only OH- can lose electrons to form water and oxygen.

The balanced chemical equation be like

4OH- --->  O2 + 2H2O + 4e-

While on the other hand, it tend to gain electrons to create new substances. Therefore, Oxygen is the gas produced.

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Answer:

v/v % = 24.522 %

Explanation:

A percent v/v solution is calculated by the following formula using the milliliter as the base measure of volume (v):

v/v % = [(volume of solute) / (volume of solution)] x 100%

In this problem, the solute is ethylene gycol.

Mass = 136.1 g

Density = 1.11 g/mL

Density = Mass / Volume

Volume = Mass / Density = 136.1 / 1.11 = 122.61 mL

Volume of solution = 500 mL

v/v % = [(volume of solute) / (volume of solution)] x 100%

v/v % = (122.61 / 500 ) x 100

v/v % = 0.24522 x 100

v/v % = 24.522 %

Considering the definition of volume percentage and density, the %v/v of the solution is 24.522%.

Volume percentage is a measure of concentration that indicates the volume of solute per 100 volume units of the solution.

In other words, percent by volume is defined as the ratio of the volume of solute to the volume of the solution.

The volume percentage of a solution is determined by the following expression:

[tex]volume percentage=\frac{volume of solute}{total volume} x100[/tex]

In this case, you know that a solution made from 136.1 g of ethylene glycol (density is 1.11 g/mL) in water to form a total volume of 500.0 mL.

Knowing that the density is a quantity that allows us to measure the amount of mass in a certain volume of a substance, the expression for the calculation of density is the quotient between the mass of a body and the volume it occupies:

[tex]density=\frac{mass}{volume}[/tex]

So, being 136.1 g of ethylene glycol (solute) with a density of 1.11 [tex]\frac{g}{mL}[/tex], the volume can be calculated as:

[tex]1.11 \frac{g}{mL} =\frac{136.1 g}{volume}[/tex]

Solving:

[tex]volumex1.11 \frac{g}{mL} =136.1 g[/tex]

[tex]volume=\frac{136.1 g}{1.11 \frac{g}{mL} }[/tex]

volume= 122.61 mL

So, you know that:

Replacing in the expresion for volume percentage:

[tex]volume percentage=\frac{122.61 mL}{500 mL} x100[/tex]

Solving:

volume percentage= 0.24522 ×100

volume percentage= 24.522 %

Finally, the %v/v of the solution is 24.522%.

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Answer:

The answer is option D.

Hope this helps you

Answer:

1. Not to have enough salt water on the foil

2.not cleaning the foil well to remove interfering materials

Answer:

- Iron is oxidized from 0 to +2.

- Hydrogen is reduced from +1 to 0.

Explanation:

Hello,

In this case, for the given reaction, we must first indicate the oxidation state of each element (notice that HC2H3O is acetic acid)

[tex]Fe ^0(s)+ 2 H^+(C_2H_3O_2)^-(aq) \rightarrow Fe^{2+}(C_2H_3O_2)_2^-(aq) + H_2^0(g)[/tex]

Thereby, notcing that iron is alone at the beginning, it has zero as its oxidation state, but once the reaction is undergone, it changes to +2, moreover, the displaced hydrogen in the acetic acid is with +1 but after the chemical reaction it becomes alone for which its oxidation state is 0, thereby, we find that:

- Iron is oxidized from 0 to +2.

- Hydrogen is reduced from +1 to 0.

Best regards,

Answer:

#1

Explanation:

molarity of EDTA solution 0.0675

no1

Answer:

There are  [tex]\mathbf{8.90172 \times 10^{-14}}[/tex] moles of bactoX present in a 3.0 μL sample volume that contains 7.512×106 bacterial cells

Explanation:

Given that:

The number of molecules present in one bacterial cell is [tex]7.140 \times 10^3[/tex] molecules

and the sample  contains [tex]7.512 \times 10^6[/tex] molecules.

Number of moles = number of molecules /Avogadro's number

where;

Avogadro's number = 6.023 × 10²³

Number of moles = [tex]\dfrac{7.140 \times 10^3}{6.023 \times 10^{23}}[/tex]

Number of moles = [tex]1.185 \times 10^{-20}[/tex] moles

So;  [tex]1.185 \times 10^{-20}[/tex] moles  is present in one bacteria cell

Similarly;  the sample  contains [tex]7.512 \times 10^6[/tex] molecules.

Therefore; the number of moles present in the bactoX is = [tex]1.185 \times 10^{-20} \times 7.512 \times 10^6[/tex]

= [tex]\mathbf{8.90172 \times 10^{-14}}[/tex] moles

Answer:

0.45 moles

Explanation:

The computation of the number of moles left in the cylinder is shown below:

As we know that

[tex]\frac{n1}{V1} = \frac{n2}{V2}[/tex]

we can say that

[tex]n2 = n1 \times \frac{V2}{V1}[/tex]

where,

n1 = 1.80 moles of gas

V2 = 12.0 L

And, the V1 = 48.0 L

Now placing these values to the above formula

So, the moles of gas in n2 left is

[tex]= 1.80 \times \frac{12.0\ L}{48.0\ L}[/tex]

= 0.45 moles

We simply applied the above formulas so that the n2 moles of gas could arrive

Answer:

8 electrons

Explanation:

The second principal energy level has two sublevels: 2s and 2p

2s : 2 electrons

2p : 6 electrons (3 sublevels × 2 electrons each = 6 electrons)

It can hold a maximum of 8 electrons.

Hope this helps. :)

Answer:

5 degrees Celsius.

Explanation:

Temperature measures the average kinetic energy of  particles of the substances. Therefore a temperature of 41 Fahrenheit is the same as 5 degree Celsius

Temperature is used to measure degree or intensity of heat of a particular substance. Temperature is measured by an instrument called thermometer.

Temperature can be measured in degree celsius °c, Kelvin k or in Fahrenheit. Temperature is a physical quantity. Heat always flow from higher temperature source to lower temperature source.

We can convert these units of temperature into one another. The relationship between degree Celsius and  Fahrenheit can be expressed as:

°C={5(°F-32)}÷9

Substituting given values in above equation

°C= {5(41-32)}÷9

°C= 5°C

Therefore a temperature of 41 Fahrenheit is the same as 5 degree Celsius

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Answer:

Number of molecules = 1.8267×10^20

Explanation:

From the question, we can deuced that the gases behave ideally, the we can make use of the ideal gas equation, which is expressed below;

PV = nRT

where

P =pressure

V =volume

n = the number of moles

R is the gas constant equal to 0.0821 L·atm/mol·K

T is the absolute temperature

Given:

P = 6.75 atm;

T = 290.0 k,

; V = 1.07 cm³ = 0.001 L

( 6.75 atm)(0.00107 L) = n(0.0821 L·atm/mol·K)(290K)

n = 3.0335167*10^-4 moles

But there are 6.022×10²³ molecules in 1 mole,

Number of molecules = 1.8267×10^20

Answer:

54

Explanation:

Mass number = protones + neutrons

Mass number = 24 + 30

Mass number = 54

Answer:

a. 621.5 mL

b. 17.5 mL

c. 0.875 moles of salt

d. 0.022 M

Explanation:

3 moles of sodium hydroxide react to 1 mol of phosphoric acid in order to produce 1 mol of sodium phosphate and 3 moles of water. The reaction is:

3 NaOH + H₃PO₄  →  Na₃PO₄  +  3H₂O

a. Ratio is 1:3. We convert the mass of the acid, to moles:

4.568 g / 97.994 g/mol = 0.0466 moles

1 mol of acid react to 3 moles of hydroxide, therefore

0.0466 moles will react to (0.0466 . 3) /1 = 0.140 moles

Molarity (M) → mmol / mL

We convert mol to mmol → 0.140 mol . 1000 mmol / 1mol = 140 mmol

mL = mmol / M → 140 mmol / 0.225M = 621.5 mL

b. Ratio is 3:1. We need to determine, the moles of base.

50 mL . 0.404 M = 20.2 mmol → 0.0202 mol of NaOH

3 moles of hydroxide react to 1 mol of acid.

20.2 mmol of hydroxide would react to (20.2 . 1) / 3 = 6.73 mmol

mL = mmol / M → 6.73 mmol / 0.385M = 17.5 mL

c. First of all, we need to find out the limiting reactant:

25 mL . 0.1050M = 2.625 mmoles of base

15mL . 0.08650M = 1.2975 mmoles of acid.

1 mol of acid need 3 moles of base, for reaction

1.2975 mmol of acid would need (1.2975 . 3) /1 = 3.8925 mmol of base

We do not have enough base, so this is the limiting. (we need 3.8925 mmoles and we only have 2.625 mmoles)

So now, we propose:

3 moles of base can produce 1 mol of salt

2.625 mmoles of base would produce (2.625 . 1) /3 = 0.875 mmoles

d. To find out molarity, we need the total volume of solution:

25 mL + 15 mL = 40 mL

0.875 mmoles of salt / 40mL of solution = 0.022 M

Answer:

322

Explanation:

This is easy

Answer:

filter the hot mixture.

Explanation:

Solid is stayed undissolved since the arrangement is gotten super saturated. On the off chance that solid molecule is available recrysallization won't happen in this way we need expel the solid molecule by filtarion in hot condition itself . Subsequently, arrangement become totally homogenous and recrysallization item will shaped by moderate cooling

Answer:

B

Explanation:

It should be 2s² which means the answer is the configuration is missing an electron in the 2s orbital.

Answer:

B.

Explanation:

It should be 2s² which means the answer

is the configuration is missing an electron

in the 2s orbital.

Answer:

160.53L

Explanation:

Since Pressure is kept constant we can use charles law

Answer:

The answer is option A.

Na4C

Hope this helps you

Answer:

Balancing the equations means adding coefficients to the reactants or products so that there is an equal amount of atoms of an element on both sides of the equation.

1) 2Mg + O₂ ⇒ 2MgO

2) 2SO₂ + O₂ ⇒ 2SO₃

3) 2Na + Cl₂ ⇒ 2NaCl

4) 4K + O₂ ⇒ 2K₂O

Answer:

198.56g of GaCl3

Explanation:

We'll begin by calculating the number of mole HCl in 2.25 L of a 1.50 M solution of HCl. This is illustrated below:

Molarity of HCl = 1.50 M

Volume = 2.25 L

Mole of HCl =..?

Molarity = mole /Volume

1.5 = mole /2.25

Cross multiply

Mole = 1.5 x 2.25

Mole of HCl = 3.375 mole

Next, we shall determine the number of mole Gallium chloride, GaCl3 produced from the reaction. This is shown below:

2Ga + 6HCl —> 2GaCl3 + 3H2

From the balanced equation above,

6 moles of HCl reacted to produce 2 moles of GaCl3.

Therefore, 3.375 mole of HCl will react to produce = (3.375 x 2)/6 = 1.125 mole of GaCl3.

Therefore, 1.125 moles of GaCl3 were produced from the reaction.

Next, we shall convert 1.125 mole of GaCl3 to grams. This is illustrated below:

Molar mass of GaCl3 = 70 + (35.5x3) = 176.5g/mol

Mole of GaCl3 = 1.125 mole

Mass of GaCl3 =..?

Mole = mass /Molar mass

1.125 = mass of GaCl3 /176.5

Cross multiply

Mass of GaCl3 = 1.125 x 176.5

Mass of GaCl3 = 198.56g

Therefore, 198.56g of GaCl3 were produced from the reaction.

Answer:

a. The pressure of a fixed amount of gas is inversely proportional to its volume.

Explanation:

At constant temperature, the relationship between pressure (P) and volume (V) illustrated in the plot for a gas gives a straight line from the origin.

This relationship was described by a law stated by Robert Boyle, an English Chemist, in 1662.

Boyle's law states that the pressure of a fixed mass of gas is inversely proportional to the volume, provided the temperature remains constant.

The relationship for Boyle’s Law can be expressed mathematically as follows:

P1V1 = P2V2; where P1 and V1 are the values of the initial pressure and volume, and P2 and V2 are the final values of the pressure and volume of the gas.

Answer:B

Explanation: I guessed and got it right. Also (1/V).

Answer:

2415.9g (corrected to 1 d.p.)

Explanation:

(Take the atomic mass of Ga=69.7 and S=32.1)

Assuming Ga is the limiting reagent (because the question did not mention the amount of sulphur burnt),

From the balanced equation, the mole ratio of Ga:Ga2S3 = 4: 2 = 2: 1, which means, every 2 moles of Ga burnt, 1 mole of Ga2S3 is produced.

Using this ratio, let y be the no. of moles of Ga2S3 produced,

[tex]\frac{2}{1} =\frac{20.5}{y}[/tex]

y = 20.5 / 2

= 10.25 mol

Since mass = no. of moles x molar mass,

the mass of Ga2S3 produced = 10.25 x (69.7x2 + 32.1x3)

= 2415.9g (corrected to 1 d.p.)

Answer:

According to Le Chatelier's principle, adding additional reactant to a system will shift the equilibrium to the right, towards the side of the products. ... If we add additional product to a system, the equilibrium will shift to the left, in order to produce more reactants.

Answer:

The type of mixture whose components are seen through our naked eyes is known as heterogeneous mixture. it is a mixture of small constituent parts of substances.

for eg, mixture of sand and sugar.

hope it helps..

Answer:

The next part is 8.8

Explanation:

You're gonna subtract 31.3 by 22.5 which is 8.8

You're welcome :)

The value of q-cal is 142.8 J in the reaction of magnesium and hydrochloric acid in a different constant pressure calorimeter with a calorimeter constant of 12.75 J/degrees Celsius.

A calorimeter is a device that measures the amount of heat in a chemical or physical process.

To calculate the value of q-cal (heat absorbed or released by the calorimeter), we need to use the following equation:

q = C * ΔT

Where q is the heat absorbed or released by the calorimeter, C is the calorimeter constant, and ΔT is the change in temperature.

In this case, we know that the calorimeter constant is 12.75 J/degrees Celsius, the initial temperature is 22.5 degrees Celsius, and the final temperature is 33.7 degrees Celsius.

Therefore, we can calculate ΔT as:

ΔT = final temperature - initial temperature

ΔT = 33.7°C - 22.5°C

ΔT = 11.2°C

Substituting these values into the equation, we get:

q = C * ΔT

q = 12.75 J/°C * 11.2°C

q = 142.8 J

Therefore, the value of q-cal is 142.8 J.

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Your question seems incomplete, the probable complete question is:

Suppose you perform the reaction of magnesium and hydrochloric acid in a different constant pressure calorimeter with a calorimeter constant of 12.75 J/degrees Celsius. The initial temperature in the calorimeter is 22.5 degrees Celsius and the final temperature after the reaction is 33.7 degrees Celsius. What is the value of q-cal?

Answer: CO2(g)+H2O(I) > H2CO3(Aq)

Explanation:

Got it right?

Answer:

2 H⁺ + 2e = H₂    ( reduction )

Explanation:

Fe( s ) + 2 CH₃COOH = Fe ( OOCCH₃ ) ₂ + H₂

Fe( s ) = Fe⁺² + 2e     ( oxidation )

2 H⁺ + 2e = H₂    ( reduction )