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2 years ago

HELPPPP!!! I NEED HELP WITH SCIENCE

Chemistry

1 answer:

pentagon [3]2 years ago

4 0

Answer:

Both are chemical changes.

Explanation:

They are chemical changes because when when you melt the sugar to make caramel a new substance is formed. The same with cookies. You don't start out with cookies, you start out with dough. And then when you cook the dough a new substance is formed which is the cookies.

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What is the difference between an imprint and an impression?

liubo4ka [24]

Answer:

As nouns the difference between impression and imprint

is that impression is the indentation or depression made by the pressure of one object on or into another while imprint is an impression; the mark left behind by printing something.

5 0

3 years ago

Aqueous hydrochloric acid (HCl) reacts with solid sodium hydroxide (NaOH) to produce aqueous sodium chloride (NaCl) and liquid w

Naddika [18.5K]

Answer:

87.9 % is the percent yield of H₂O

Explanation:

This is the neutralization reaction. A base reacts with an acid to produce water and the correspondly ionic salt.

NaOH + HCl → NaCl + H₂O

As we have the mass of the two reactants, we must determine the limiting reactant.

Let's convert to moles, the mass of each reactant. (mass / molar mass)

21.1 g / 36.45 g/mol = 0.579 moles of HCl

46.3 g / 40g/mol = 1.15 moles of NaOH

Ratio is 1:1, so it is obviously that the limiting reactant is the HCl. For 1.15 moles of NaOH, i need the same amount of acid, but I only have 0.579 moles

Let's work with the products now. Ratio is 1:1 again, so If I have 0.579 moles of acid, I can produce 0.579 moles of H₂O.

How many grams are 0.579 moles of water? We should find it out as this

mol . molar mass = mass → 0.579 mol . 18 g/mol = 10.4 g

We were told that the production of water was 9.17 g, so let's determine the percent yield as this:

(Yield produced / Theoretical yield) . 100 =

(9.17 g / 10.4g ) . 100 = 87.9 %

6 0

3 years ago

Which of the following is an

eimsori [14]

Answer:

2 and 4

Explanation:

The rest of the changes are chemical. 1 has a chemical reaction happen which makes light sticks glow. 3 is because browning the meat actually causes some new compounds to form and cause caramelization.

For 2, the oxygen is simply heating up and expanding which pops the balloon. 4 is just a phase change of water vapor to liquid water.

5 0

2 years ago

An increase in temperature affects the reaction rate by >decreasing the velocities of particles that collide in the reaction.

Bond [772]

Answer:

increasing the number of molecules that have sufficient kinetic energy to react.

Explanation:

An increase in temperature affects the reaction rate by increasing the number of molecules that have sufficient kinetic energy to react.

or we say; temperature increase, leads to an increase in the amount of collisions between molecules.

4 0

3 years ago

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Draw the structure of the organic product(s) of the grignard reaction between phosgene (clcocl) and excess phenylmagnesium bromi

Jobisdone [24]

Phosgene on reacting with <span>phenylmagnesium bromide generates benzoyl chloride.

Since, </span>phenylmagnesium bromide is added in excess. It would further react with benzoyl chloride to form benzophenone.

Benzophenone on further reacting with phenylmagnesium bromide, and aqueous treatment, gives triphenylmethanol.

Entire reaction pathways is shown below:

8 0

3 years ago

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