Chemistry Middle School

What is the concentration of a HF solution with a PH of 2.3

Answers

Answer 1
Answer:
             [H⁺]  =  5.011 × 10⁻³ mol.L⁻¹

Explanation:

The pH is converted into concentration of H⁺ as,

[H⁺]  = 10^-pH

Where 10 is antilog,

So, putting values,

[H⁺]  =  10⁻²·³

[H⁺]  =  0.00501

Or,

[H⁺]  =  5.011 × 10⁻³ mol.L⁻¹

Related Questions

Acceleration involves a change in __________.

Answers

Acceleration involves itself in a change in “speed and direction”. Not either or.
Acceleration involves a change in speed and direction.

A bottle contains 6.23 g of copper turnings. The mass of a length of magnesium ribbon is 6.23 g. Are there more copper atoms or more magnesium atoms present?

Answers

Moles = mass (g) / molar mass (g/mol)

Molar mass of copper = 63.5 g/mol
Molar mass of magnesium = 24.3 g/mol

Moles of copper = 6.23 g / 63.5 g/mol = 0.098 mol

Moles of magnesium = 6.23 g / 24.3 g/mol = 0.256 mol

according to the Avogadro constant,
                           1 mol = 6.022 x 10²³

Hence,
 atoms of copper        = 0.098 x 6.022 x 10²³ = 5.902 x 10²²
 atoms of magnesium = 0.256 x 6.022 x 10²³ = 15.416 10²²

Hence magnesium ribbon has more atoms.


A sample of gas at 301 Kelvin and 1.5 atmospheres has a density of 3.90 g/L. What is the molar mass of this gas? Show all of the work used to solve this problem.

Answers

PV = nRTP is pressure, V is volume in L, n is number of moles, R is the gas constant,and T is temperature in K

(1.5 atm)(1 L) = (n)(.08206)(301K)

n = .06 moles in one liter

If there are 3.9 grams in .06 moles then

1/.06 x 3.9 = 64.2 grams per mol


Answer:

Molar mass of the gas is 64.3 g/mol

Explanation:

Given:

Temperature of gas, T = 301 K

Pressure of gas, P = 1.5 atm

Density of gas, D = 3.90 g/L

To determine:

The molar mass, M of the gas

Explanation

Based on the ideal gas equation

[tex]PV = nRT[/tex]

where P = pressure, V = volume ; R = gas constant, T = temperature

n = moles of the gas

[tex]n = \frac{mass(m)}{molar\ mass(M)}[/tex]

substituting for n in the ideal gas equation:

[tex]PV = \frac{m}{M} *RT\\\\M = (\frac{m}{V})*\frac{RT}{P}  \\\\density , d = \frac{mass(m)}{Volume(V)} \\\\Therefore:\\\\M = d*\frac{RT}{P} = 3.90 g/L *\frac{.0821Latm/mol-K*301K}{1.5atm} =64.3 g/mol[/tex]

What is the value for ΔS°reaction for the following reaction, given the standard entropy values
C6H12O6(s) + 6O2(g) —->6CO2(g) + 6H2O(l)
+131 j/k
-131 j/k
+262j/k
-262 j/k
+417j/k

Answers

Standard entropy of the compounds of interest are as follows, 
[tex] S^{0} (C6H12O6) [/tex] = 212.1 J/K.mol
[tex] S^{0} (O2) [/tex] = 205.0 J/K.mol
[tex] S^{0} (CO2) [/tex] = 213.6 J/K.mol
[tex] S^{0} (H2O) [/tex] = 69.9 J/K.mol

Now for the reaction: 
C6H12O6(s) + 6O2(g) —->6CO2(g) + 6H2O(l)

ΔS°reaction = ∑[tex] S^{0} products [/tex] - ∑[tex] S^{0} reactants [/tex]
∴ ΔS°reaction =( 6 [tex] S^{0} (CO2) [/tex] + 6 [tex] S^{0} (H2O) [/tex] ) - ([tex] S^{0} (C6H12O6) [/tex] + 6 [tex] S^{0} (O2) [/tex] = 205.0 J/K.mol)
∴ ΔS°reaction = [6 (213.6) + 6 (69.9 )] - [(212.1) + 6(205.0)]
∴ ΔS°reaction = 258.9 ≈ 262 J/ K mol.

Thus, correct answer is option C
The answer is C. 262 J/ K mol.

Molar mass:
C6H12O6212.1 J/K.mol
O2= 205.0 J/K.mol
CO2 = 213.6 J/K.mol
H2O= 69.9 J/K.mol

THE BALANCE IS:
C6H12O6(s) + 6O2(g) —->6CO2(g) + 6H2O(l)

= [6 (213.6) + 6 (69.9 )] - [(212.1) + 6(205.0)]
= 258.9 
=262 J/ K mol.

When determining the motion of the planets in the solar system what is a good reference point to use

Answers

the sun is the answer

Jimmer is playing basketball. After 24 seconds, the shot clock goes off and he loses the ball. This happens every time he gets the ball because he refuses to pass or shoot. Which of the following statements is true?
Jimmer is on a fixed-interval schedule of reinforcement.
Jimmer is on a variable-interval schedule of reinforcement.
Jimmer is on a fixed-ratio schedule of reinforcement.
Jimmer is on a variable-ratio schedule of reinforcement.

Answers

Answer:

The answer is A- Jimmer is on a fixed-interval schedule of reinforcement.

Explanation:

Final answer:

Jimmer is on a fixed interval reinforcement schedule, as he loses the ball every 24 seconds, which is a predictable and set amount of time after he initially gets possession.

Explanation:

Jimmer, in the scenario provided, loses the ball after 24 seconds each time he gets the ball because he refuses to pass or shoot, thus triggering the shot clock.

Jimmer is on fixed interval reinforcement schedule.

This is because his behavior (holding onto the ball) is being 'rewarded' with the loss of the ball at a predictable and set amount of time after he first acquires it, which is every 24 seconds.

A fixed interval schedule of reinforcement is when reinforcement is received after a certain fixed period of time has passed, as opposed to variable interval schedules where the period of time varies, and the ratio schedules where reinforcement is based on the number of responses rather than the passage of time.

Calculate the answer. Express it in scientific notation and make sure it has the correct number of significant figures. (2.45 x 1013) x (4.00 x 1012) = _____

Answers

The answer is 10,046,528.8 !

(2.45 x 10^13) x (4.00 x 10^12) = 9.8 x 10^25

Hope this helps!

How many double bonds are in an alkane?

Answers

None
Alkanes only have single bonds
Final answer:

Alkanes are hydrocarbons with only single bonds between the carbon atoms, therefore, they do not contain any double bonds.

Explanation:

In chemistry, an alkane is a type of hydrocarbon where all of the carbon-carbon bonds are single bonds, meaning they share just one pair of electrons. Double bonds share two pairs of electrons and are typically found in alkenes, a different type of hydrocarbon. Therefore, an alkane does not have any double bonds.

Learn more about Alkanes here:

https://brainly.com/question/35822742

#SPJ6

NaCl, I2, HCl, KF what kind of bond are they?

Answers

The type of bond is determined based on if the bond is between an metal and a non-metal, or two non-metals. The metal-nm bond is ionic, and the two non-metal bond is covalent. Therefore:

NaCl - ionic
I2 - covalent
HCl - covalent
KF - ionic

Final answer:

NaCl, I2, HCl, and KF have different types of bonds: NaCl and KF have ionic bonds, while I2 and HCl have covalent bonds.

Explanation:

The compounds NaCl, I2, HCl, and KF have different types of bonds.

NaCl, sodium chloride, has an ionic bond. In an ionic bond, one atom donates electrons to another atom to form ions with opposite charges.

I2, iodine, has a covalent bond. In a covalent bond, atoms share electrons to fill their valence shells.

HCl, hydrogen chloride, also has a covalent bond.

KF, potassium fluoride, has an ionic bond. The metal atom donates electrons to the non-metal atom.

how many atoms of each element are needed to create an ionic compound of strontium selenide

Answers

Step 1:
           Calculate the ionic charges on both atoms:

As Strontium belongs to Group-II in periodic table so it will tend to loose two electrons and form Sr⁺² , i.e.

                                        Sr    →     Sr⁺²  +  2 e⁻

While, Se belonging to Group-VI will tend to gain two electrons and form Se⁻², i.e. 

                                       Se  +  2 e⁻    →    Se⁻²

Step 2:
           Multiply the coefficient of each element by the charge of other element.

                                    Se⁻² × 2  =  2 Se⁻²           ∴ where 2 is charge on Sr
And,
                                    Sr⁺² × 2  =  2 Sr⁺²             ∴ where 2 is charge on Se

So, the formula comes out to be,

                                                  Sr₂Se₂

Or divide both coefficients by 2 to have a simplest form. i.e...

                                                    SrSe

Result:
           One One atoms of each element are needed to create an ionic compound of Strontium Selenide.

Balance the following: ___ AlBr3+ ___ K---> ___KBr+ ___ Al

Answers

___AlBr3 + ___K -> ___KBr + ___ Al

1 AlBr3 + 3K -> 3KBr + 1 Al

hope this helps............
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