Ice caps blank more light than deserts because they have a higher albedo?

What is the [h3o ] for a solution of seawater at 25°c that has a ph of 8.3?

Kipish [7]

PH of solution at 25ºC = 8.3

$[ H_3O^+] = 10 ^{-pH}$

${H_3O^+] = 10 ^{-8.3}$

$[H_3O^+] = 5.011*10^{-9} M$

hope this helps!

6 0

3 years ago

How many grams of NaCl are needed to make 0.800 liter of a 5.00 M solution?

ziro4ka [17]

Answer:

0.324 g is required to make 5.00 M solution of NaCl in 0.800 L.

Given data:

Molarity = 5.00 M

Formula Mass = 58.5 g/mol

Required volume = 0.800 L

To Find;

Mass in gram = ?

Solution:

Formula for calculating mass in gram is given as,

Mass in gram = Molarity × Formula mass × Volume required / 1000 putting values

Mass in gram = 5.00 M × 58.5 g/mol × 0.800 L / 1000

Mass in gram = 0.234 g

6 0

4 years ago

Using the equations

Anna [14]

Considering the Hess's Law, the enthalpy change for the reaction is 221.8 kJ/mol.

Hess's Law indicates that the enthalpy change in a chemical reaction will be the same whether it occurs in a single stage or in several stages. That is, the sum of the ∆H of each stage of the reaction will give us a value equal to the ∆H of the reaction when it occurs in a single stage.

In this case you want to calculate the enthalpy change of:

C₂H₄ (g) + 6 F₂ (g) → 2 CF₄ (g) + 4 HF (g)

which occurs in three stages.

You know the following reactions, with their corresponding enthalpies:

Equation 1: H₂ (g) + F₂ (g) → 2 HF (g) ∆H° = -79.2 kJ/mol

Equation 2: C (s) + 2 F₂ (g) → CF₄ (g) ∆H° = 141.3 kJ/mol

Equation 3: 2 C(s) + 2 H₂ (g) → C₂H₄ (g) ∆H° = -97.6 kJ/mol

Because of the way formation reactions are defined, any chemical reaction can be written as a combination of formation reactions, some going forward and some going back.

<h3 /><h3>FIRST STEP</h3>

First, to obtain the enthalpy of the desired chemical reaction you need one mole of C₂H₄ (g) on reactant side and it is present in first equation. Since this equation has one mole of C₂H₄ (g) on the product side, it is necessary to locate it on the reactant side (invert it).

When an equation is inverted, the sign of ΔH° also changes.

<h3>SECOND STEP</h3>

Now, you need 2 moles of CF₄ (g) on the product side. The second equation has 1 mole of CF₄ (g) on the product side, so it is necessary to multiply it by 2 to obtain 2 moles of CF₄ (g).

Since enthalpy is an extensive property, that is, it depends on the amount of matter present, since the equation is multiply by 2, the variation of enthalpy also.

<h3>THIRD STEP</h3>

Finally, you need 4 moles of HF (g) on the product side. The first equation has 2 moles of HF (g) on the product side, so it is necessary to multiply it by 2 to obtain 4 moles of the compound.

Since the equation is multiply by 2, the variation of enthalpy also is multiplied by 2.

<h3>SUMMARY</h3>

In summary, you know that three equations with their corresponding enthalpies are:

Equation 1: 2 H₂ (g) + 2 F₂ (g) → 4 HF (g) ∆H° = -158.4 kJ/mol

Equation 2: 2 C (s) + 4 F₂ (g) → 2 CF₄ (g) ∆H° = 282.6 kJ/mol

Equation 3: C₂H₄ (g) → 2 C(s) + 2 H₂ (g) ∆H° = 97.6 kJ/mol

Adding or canceling the reactants and products as appropriate, and adding the enthalpies algebraically, you obtain:

C₂H₄ (g) + 6 F₂ (g) → 2 CF₄ (g) + 4 HF (g) ΔH°= 221.8 kJ/mol

Finally, the enthalpy change for the reaction is 221.8 kJ/mol.

Learn more about molar enthalpy:

7 0

2 years ago

Which type of crust combination CANNOT undergo subduction?

nordsb [41]

Answer:

the correct answer is B

Explanation:

Subduction: they present if or if two Convergent edges or subduction zones (destructive edges). Where two plates collide, due to having movements with opposite directions, the denser one sinks below the less dense one along what is known as the subduction zone; the subducting plate goes into the mantle, heating up and partially melting generating magma that rises to the surface. A subduction zone is characterized by deformation, volcanism, mountain formation, metamorphism, seismic activity, and significant mineral deposits.

This phenomenon occurs between oceanic plates or between a continental and an oceanic plate, since when there is a difference in density they subduct.

In the event that the edges of two continental plates collide, it would be OBDUCTION, which is another phenomenon other than subduction. mantle does not produce the correct subduction process, as the movement must be absorbed in some way, this is carried out by vertically deforming both plates, which are joined by a suture area, forming an inner mountainous belt and Suffering, in addition, numerous earthquakes. This process is very important, since it is the one that has given rise to the highest mountain ranges on Earth and is a very active process at present (Ex: Los Alpes, Los Montes Urales and Montes Himalaya).

6 0

3 years ago

Tris has a molecular weight of 121 g/mol. How many grams of Tris would you need to make 100 mL of a 100 mM solution of Tris

Zepler [3.9K]

Answer:

1.21 g of Tris

Explanation:

Our solution if made of a solute named Tris

Molecular weight of Tris is 121 g/mol

[Tris] = 100 mM

This is the concentration of solution:

(100 mmoles of Tris in 1 mL of solution) . 1000

Notice that mM = M . 1000 We convert from mM to M

100 mM . 1 M / 1000 mM = 0.1 M

M = molarity (moles of solute in 1 L of solution, or mmoles of solute in 1 mL of solution). Let's determine the mmoles of Tris

0.1 M = mmoles of Tris / 100 mL

mmoles of Tris = 100 mL . 0.1 M → 10 mmoles

We convert mmoles to moles → 10 mmol . 1mol / 1000mmoles = 0.010 mol

And now we determine the mass of solute, by molecular weight

0.010 mol . 121 g /mol = 1.21 g

8 0

3 years ago