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2 years ago

In a science experiment, Javi concludes that a chemical reaction has occurred. What evidence would support this conclusion?

Chemistry

2 answers:

Naily [24]2 years ago

8 0

Answer:

B) a substance's color and odor changed Explanation: A signal that a chemical change has occurred is when its odor (its smell) or its appearance has changed.

Romashka [77]2 years ago

6 0

Answer:

that correct answer is The product is not poisonous or odorous like chlorine, and it’s no longer a metal like sodium. It does not have the same properties as either reactant. Also, the white “dust” in the video indicates that a reaction has taken place.

Explanation:

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The anion formed from an oxygen atom is called a(n)

marta [7]

A. Oxygen ion
I am not sure but that's the right one I think. If I am wrong then I am sorry

6 0

3 years ago

To indicate the pH of a substance, one can use a dye that is both an acid and that appears as different colors in its protonated

PIT_PIT [208]

Answer:

<em>The pH of the solution is 7.8</em>

Explanation:

The concentration of the solution is 0.001M and the dye could be in its protonated and deprotonated forms. If the concentration of the protonated form [HA] is 0.0002 M the concentration of the deprotonated form will be the subtraction between the concentration of the bye and the concentration of the protonated form:

[A-] = 0.001M - 0.0002M = 0.0008M

Also, the Henderson-Hasselbalch equation is

$pH = pKa + Log \frac{[A^{-}]}{[HA]}$

this equation shows the dependency between the pH of the solution, the pKa and the concentration of the protonated and deprotonated forms. Thus, replacing in the equation

$pH = 7.2 + Log \frac{0.0008M}{0.0002M} = 7.8$

3 0

3 years ago

Valance shell example..

Natali5045456 [20]

Answer:

<h2>Oxygen has six valence electrons, two in the 2s subshell and four in the 2p subshell.</h2>

<h3>Valence electrons are the electrons in the outermost shell, or energy level, of an atom. </h3>

<h3>Configuration of oxygen's valence electrons as 2s²2p⁴.</h3>

Explanation:

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3 0

2 years ago

C3H8(g) + 5O2(g) ⟶ 3CO2(g) + 4H2O(g) H = -2220 kJ If 865.9 g of H2O is produced during this combustion, how much heat is generat

dem82 [27]

Answer:

3 × 10⁴ kJ

Explanation:

Step 1: Write the balanced thermochemical equation

C₃H₈(g) + 5 O₂(g) ⟶ 3 CO₂(g) + 4 H₂O(g) ΔH = -2220 kJ

Step 2: Calculate the moles corresponding to 865.9 g of H₂O

The molar mass of H₂O is 18.02 g/mol.

865.9 g × 1 mol/18.02 g = 48.05 mol

Step 3: Calculate the heat produced when 48.05 moles of H₂O are produced

According to the thermochemical equation, 2220 kJ of heat are evolved when 4 moles of H₂O are produced.

48.05 mol × 2220 kJ/4 mol = 2.667 × 10⁴ kJ ≈ 3 × 10⁴ kJ

5 0

2 years ago

write an activity to show the change in state and change in temperature during a chemical reaction(change)

Paha777 [63]

If a piece of charcoal is taken and set on fire it will evolve CO2 and heat. Charcoal is solid but carbon dioxide is gaseous. This is an example of change of state and evolve of heat during chemical reaction.

5 0

3 years ago