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3 years ago

In which scenario is a chemical change occurring?

Chemistry

2 answers:

fenix001 [56]3 years ago

4 0

the answer is A because had this question before

Dimas [21]3 years ago

4 0

Answer is C because each of the above cause a change in state, hence it’s physical, the molecules remain same.
But corrosion is a chemical change, cause there is an addition of water and air to the regular iron molecules

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Balance the combustion eqation; __C5H + __O2 ---> __CO2+__H2O

stira [4]

This equation C5H + O2 ---> CO2 + H2O has a mistake.

C5H is wrong. You missed the subscript of H.

I will do it for you assuming some subscript to show you the procedure, but you have to use the right equation to get the right balanced equation.

Assuming the tha combustion equation is C5H12 + O2 ---> CO2 + H2O

First you need to balance C, so you put a 5 before CO2 and get

C5H12 + O2 ---> 5CO2 + H2O

Now you count the hydrogens: 12 on the left and 2 on the right. So put a 6 before H2O and get:

C5H12 + O2 ---> 5CO2 + 6H2O

Now count the oxygens: 2 on the left and 16 on the right, so put an 8 on before O2:

=> C5H12 + 8O2 ---> 5CO2 + 6H2O.

You can verify that the equation is balanced

8 0

3 years ago

Chemists can use moles to calculate: A. How much of the products are needed and how much reactant will be made. B. How much prod

damaskus [11]

Answer:

c.- How much of the reactants are needed and how much product will made.

Explanation:

The moles is the matter unit used in chemistry to simplify some calculations, instead of using grams. Also the moles are very useful because the chemical reaction can be balanced.

When a Chemical reaction is balanced, then it can be easily to calculate how many moles are necessary to add in a process to obtain a quantity of grams of a product.

5 0

3 years ago

Balance the following chemical equation.<br><br> CCl4 -> ___ C+ ___ Cl2

Bingel [31]

Answer:

Explanation:

CCl4 => C + 2Cl2

6 0

3 years ago

Which of the following measurements is used to measure the enthalpy of combustion? A. None of these B. Measuring the change in t

DaniilM [7]

Answer: Option (C) is the correct answer.

Explanation:

In a substance, the total energy of its molecular motion is known as heat. Whereas when we measure the average energy of molecular motion of a substance then it is known as temperature.

So, any increase or decrease in temperature will lead to change in heat of a substance.

When one mole of a substance is burned then the amount of energy released in the form of heat is known as heat of combustion.

Relation between heat and temperature is as follows.

q = $m \times C \times \Delta T$

Thus, we can conclude that to measure the enthalpy of combustion it cannot be measured, only calculated using the equation; q = $mc \Delta T$ .

4 0

3 years ago

A formic acid buffer solution contains 0. 20 m h c o o h hcooh and 0. 24 m h c o o − hcoox−. the pka of formic acid is 3. 75. wh

irina1246 [14]

A buffer solution contains an equivalent amount of acid and base. The pH of the solution with an acid dissociation constant (pKa) value of 3.75 is 3.82.

The amount of hydrogen or the proton ion in the solution is expressed by the pH. It is given by the sum of pKa and the log of the concentration of acid and bases.

Given,

Concentration of salt [HCOO⁻] = 0.24 M

Concentration of acid [HCOOH] = 0.20 M

The acid dissociation constant (pKa) = 3.75

pH is calculated from the Hendersons equation as,

pH = pKa + log [salt] ÷ [acid]

pH = 3.75 + log [0.24] ÷ [0.20]

= 3.75 + log (1.2)

= 3.75 + 0.079

= 3.82

Therefore, 3.82 is the pH of the buffer.

Learn more about pH here:

brainly.com/question/27181245

#SPJ4

6 0

2 years ago