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2 years ago

Help me please i dont understand

Chemistry

2 answers:

Lelechka [254]2 years ago

6 0

Answer:

1. Dissolving powder in milk - Chemical

- It is chemical because the milk has changed on a molecular level

2. Toasting bread - Chemical

- It is chemical because adding heat to the bread cooks it, therefore

changing it on a molecular level

3. Melting cheese - Physical

- It is physical because the physical appearance was the only change

4. Slicing apples or bannanas - Physical

- It is physical because the physical appearance was the only change

5. Frying an egg - Chemical

- It is chemical because new particles were formed

6. Milk souring - Chemical

- It is chemical because it is forming a new product (lactic acid)

Explanation:

Physical Change occurs when the particles of a substance become rearranged, but do not change into different particles.

Chemical change occurs when a new substance is formed. This process is irreversable.

Dvinal [7]2 years ago

3 0

Answer:

give the preson above brainly bc there right

Explanation:

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in the future, clean energy sources, such as solar power, may be used to create hydrogen fuel true false

borishaifa [10]

False, b/c you can't turn electricity into a fuel

3 0

3 years ago

Read 2 more answers

7. When solid carbon reacts with oxygen gas to produce carbon dioxide gas, woul the triangle H value be on the reactant or produ

garik1379 [7]

When solid carbon reacts with oxygen gas to produce carbon dioxide gas. the deltaH (enthalpy change ) value is negative .DeltaH would be on the product side of the equation.

<h3>What is enthalpy change? </h3>

In a thermodynamic system, energy is measured by enthalpy. Enthalpy is a measure of a system's overall heat content and is equal to the system's internal energy plus the sum of its volume and pressure.

Knowing whether q is endothermic or exothermic allows one to characterise the relationship between q and H. An endothermic reaction is one that absorbs heat and demonstrates that heat from the environment is used in the reaction, hence q>0 (positive). For the aforementioned equation, under constant pressure and temperature, if q is positive, then H will also be positive. In a similar manner, heat is transferred to the environment when it is released during an exothermic reaction. Thus, q=0 (negative). Therefore, if q is negative, H will also be negative.

Learn more about enthalpy change here :

brainly.com/question/1445358

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7 0

1 year ago

Write a balanced equation for its combustion reaction.

laila [671]

<h3>Answer:</h3>

C₅H₁₂O(l)+15/2O₂(g)→5CO₂(g)+6H₂O(l)

<h3>Explanation:</h3>

The balanced chemical equation for the combustion of the hydrocarbon in question is;

C₅H₁₂O(l)+15/2O₂(g)→5CO₂(g)+6H₂O(l)

A balanced chemical equation is one in which the number of atoms of each element is equal on both sides of the equation.

In this case;

Reactant side has; 5 carbon atoms, 12 hydrogen atoms and 16 Oxygen atoms
Product side has; 5 carbon atoms, 12 hydrogen atoms and 16 Oxygen atoms

An equation is balanced by putting appropriate coefficients on reactants and products involved in the reaction.
An equation is balanced so as to obey the law of conservation of mass.

5 0

3 years ago

An obese man was discovered in his air-conditioned hotel room sitting in a chair in front of the television. The air conditioner

Leno4ka [110]

Answer:

It has been approximately 6 hours after death.

Explanation:

This is because between 2-6 hours after death, the body starts becoming stiff from top to bottom, then spreading to the limbs. Since there is only rigor in his upper body, that would mean that with normal temperature and body conditions, it would be 4 or 5 hours after death. But since he is obese and in cold temperature, there is slower progression of rigor, leading to the maximum time in the first rigor mortis phase, 6 hours.

8 0

3 years ago

Draw the structure(s) of the major organic product(s) of the following reaction. 1. lithium diisopropylamide / hexane 2. 1 eq. C

Jobisdone [24]

Answer:

See explanation below

Explanation:

You are not providing the starting material, however, I manage to find a similar question to this, so I'm gonna use it as a basis to help you answer yours.

Now let's analyze what is happening in the reaction so we can predict the final product.

We have a ketone here, reacting at first with LDA. This is a very strong base that is commonly used in reactions with ketones and aldehydes to promove a condensation. To do this, as LDA is a strong base it will occur firts an acid base reaction, substracting the most acidic hydrogen in the molecule (Which in this case, is the Beta hydrogen of the carbonile). This will cause an enolate formation.

Then, this enolate will react with the CH3I and form a new product. The final result would be a ketone with a methyl group now attached. In the picture 2, you have the mechanism and final product.

Hope this helps

6 0

3 years ago