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Marrrta [24]
2 years ago
8

Which of the following hypotheses is testable by using the scientific method?

Chemistry
1 answer:
Paraphin [41]2 years ago
5 0

Answer:

D

Explanation:

Because it is the only was that you can test using the scientific method.

You might be interested in
Consider the reaction: 2HI(g) ⇄ H2(g) + I2(g). It is found that, when equilibrium is reached at a certain temperature, HI is 35.
Sliva [168]

Answer:

Kc = 0.075

Explanation:

The dissociation (α) is the initial quantity that ionized divided by the total dissolved. So, let's calling x the ionized quantity, and M the initial one:

α = x/M

x = M*α

x = 0.354M

For the stoichiometry of the reaction (2:1:1), the concentration of H₂ and I₂ must be half of the acid. So the equilibrium table must be:

2HI(g) ⇄   H₂(g) +    I₂(g)

M               0             0               <em> Initial</em>

-0.354M  +0.177M  +0.177M       <em>Reacts</em>

0.646M     0.177M   0.177M        <em>Equilibrium</em>

The equilibrium constant Kc is the multiplication of the products' concentrations (elevated by their coefficients) divided by the multiplication of the reactants' concentrations (elevated by their coefficients):

Kc = \frac{[H2]*[I2]}{[HI]^2}

Kc = \frac{0.177M*0.177M}{(0.646M)^2}

Kc = \frac{0.03133M^2}{0.41732M^2}

Kc = 0.075

5 0
3 years ago
an acid accepts H and removes them from a solution, is a solution where the water molecules are intact
n200080 [17]
<h3>An acid accepts H and removes them from a solution</h3>

When placed in water, acids, bases, and salts dissociate (separate) into electrolytes (ions). Salts dissociate into a cation (that is not H+) and an anion (that is not OH-), whereas acids and bases dissociate into H+ and an anion. An acid separates into anions and hydrogen ions (H+). Strong acids produce a high concentration of H+ by dissociating every single one of their molecules . Water-based solutions,

Acid:

When a material or chemical is in solution, it releases hydrogen ions (H+), which are known as acids. All hydrogen ions (H+) and chloride ions (Cl-), which are normally bound together by ionic bonding, dissociate (separate) in water when exposed to a strong acid like hydrochloric acid (HCl). Only some ions disintegrate into hydrogen ions (H+) and bicarbonate ions (HCO3-) in a weak acid like carbonic acid (H2CO3), while others are still bound together by ionic bonds.

Define base?

A base is a chemical that, when in solution, emits hydroxyl ions -{OH). We can also define a base as a substance that releases hydroxyl ions (OH-), which mix with any hydrogen ions (H+) in the solution to generate water molecules (OH- + H+ = H2O).

Therefore, a substance that receives or accepts hydrogen ions (H+) that are already present in the solution qualifies as a base.

Because it totally dissociates into sodium ions (Na+) and hydroxyl ions (OH-) when placed in water, sodium hydroxide (NaOH), which is a strong base, is now liberated and dissolves in water.

c

for more information please visite:

brainly.com/question/15017356?referrer=search

#SPJ4

8 0
2 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:

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7 0
2 years ago
How many atoms of Kr (Krypton) are in a balloon that contains 2.00 mol of Kr? (4)
Svetllana [295]

Answer:

atoms= 1.204x10^{24}atoms

Explanation:

Hello!

In this case, according to the Avogadro's number, it is possible to compute the atoms of Kr in 2.00 moles as shown below:

atoms=2.00mol*\frac{6.022x10^{23}atoms}{1mol} \\\\atoms= 1.204x10^{24}atoms

Best regards!

4 0
2 years ago
Which instrument is used to measure mass?
alexdok [17]

Answer:

Balance

Explanation:

hope i helped

7 0
3 years ago
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