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MArishka [77]
3 years ago
15

Which of the following is not a clue that a chemical reaction has taken place? *

Chemistry
1 answer:
DaniilM [7]3 years ago
7 0

Answer:

A pure solid is heated and turns into a pure liquid.

Explanation:

No colour change recorded, only change of state, hence this is a physical change - physical changes I.e. change of state and temperature are not chemical reactions.

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Based on the kinetic theory, which statement is true?
Citrus2011 [14]

Answer:

(D) The particles of matter are arranged in different ways for the different states.

Explanation:

The particles of matter arrange differently based on the different states

They don't stay the same for each state. They have to change depending on certain things.

5 0
3 years ago
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trasher [3.6K]
Protons are positive
3 0
3 years ago
Chemical reactions occur when molecules or atoms collide, the bonds between atoms are broken, and new bonds are formed.
schepotkina [342]

Answer:

A. Decreasing the temperature decreases the kinetic energy of the reactants, and the reaction goes more slowly.

C. Reactants must collide, with proper orientation, with energy greater than or equal to the activation energy for a reaction to occur.

D. Increasing the amount of reactants increases the number of collisions, and the reaction goes faster.

F. The energy of a collision between atoms or molecules must be greater than or equal to the activation energy (Ea) for bonds to be broken.

Explanation:

Decreasing the temperature decreases the kinetic energy of the reactants, so fewer molecules have enough kinetic energy to get over the Eₐ barrier, and the reaction goes more slowly.

Reactants must collide, with proper orientation, with energy greater than or equal to Eₐ for a reaction to occur.

Increasing the concentration of reactants increases the frequency of collisions, so the number of successful collisions increases.

The energy of a collision between atoms or molecules must be greater than or equal to Eₐ for bonds to be broken.

B is wrong. If Eₐ is low, more of the molecules can get over the energy barrier, and the reaction rate is fast.

E is wrong. If the energy of the products is higher than the energy of the reactants, the products must have gained energy. The reaction is endothermic.

G is wrong. Eₐ is the energy difference between the energy of the transition state and that of the reactants.

8 0
3 years ago
What is the mole ratio of D to A in the generic chemical reaction? 4A + B --&gt; C + D​
storchak [24]
<h3>Answer:</h3>

Mole ratio of D to A is 1 : 4

<h3>Explanation:</h3>

We are given the generic chemical equation;

4A + B → C + D​

We are supposed to determine the mole ratio of D to A

What is mole ratio?

  • Mole ratio is the ratio of the number of moles of reactants or products in a chemical reaction.
  • We determine the mole ratio using the coefficients of reactants or products in question.

For example;

  • In the equation, 4A + B → C + D​, the coefficient of A is 4 while the coefficient of D is 1.
  • This means, 4 moles of A reacts with 1 mole of b to produce 1 mole of C and 1 mole of D
  • Thus, mole ratio of D to A  is 1 : 4
6 0
3 years ago
What is the molarity of a 750 milliliters solution containing 54.0 grams of KBr (help me please)
ololo11 [35]

<u>Answer:</u> The molarity of KBr solution is 0.605 M

<u>Explanation:</u>

Molarity is defined as the amount of solute expressed in the number of moles present per liter of solution. The units of molarity are mol/L.

The formula used to calculate molarity:

\text{Molarity of solution}=\frac{\text{Given mass of solute}\times 1000}{\text{Molar mass of solute}\times \text{Volume of solution (mL)}}       .....(1)

Given values:

Given mass of KBr = 54.0 g

Molar mass of KBr = 119 g/mol

Volume of the solution = 750 mL

Putting values in equation 1, we get:

\text{Molarity of solution}=\frac{54.0\times 1000}{119\times 750}\\\\\text{Molarity of solution}=0.605M

Hence, the molarity of KBr solution is 0.605 M

7 0
3 years ago
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