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stira [4]
3 years ago
7

PLease help! im really desperate Right now 20pts

Chemistry
1 answer:
inna [77]3 years ago
7 0

Answer:

Q1: Bubbles (gas formation)

     Dissolving ( if solute is an ionic compound)

     Color change

Q2: Fire burning

      Salt dissolving

Q3: Bubbles (gas formation)  

       Color change

      Dissolving ( if solute is an ionic compound)

Explanation:

Bubbles (gas formation)

Gas formation is mostly taken as an indicator for a chemical reaction, mostly in acid base reactions. Because when acid and base reacts water and carbon dioxide produces.

Dissolving of salt

Dissolving of salt in water is an example of a chemical change. Because when we put salt (NaCl) in water it changes into its ions (Na⁺ Cl⁻) by losing or gaining electrons. These Ions have totally different properties from the parent salt. So it is a chemical change.

Color change

Mostly we take color change as an indicator of a chemical change but it is not necessary. For example when we add two colors in a beaker its changes into a 3rd color without any chemical reaction.

Fire burning

Fire burning is an example of a chemical change. For example during wood burning, a chemical reaction takes place which changes the into ash and CO₂. the reactants and products have totally different properties.

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Answer:

RAM

RAM = (mass \: of \:  ^{28} Si \:  \times \%abundance) + (mass \: of \:  ^{30} Si \:  \times \%abundance) \\ RAM = (28 \times 90\%) + (30 \times 10\%) \\ RAM = 25.2 + 3 \\ RAM = 28.2

5 0
3 years ago
Show the difference in the reactivity of Na,Ca,Mg,Al,Fe,Cu with H2O
Vesnalui [34]

Answer:

Explanation:

Na react with H2O to form NAOH

2 Na+2H2O....................2NAOH + H2

Ca react with water and form calcium hydroxide

Ca + 2H2O........................Ca(OH)2

Mg react with water and form Magnesium hydroxide

Mg +2H2O .........................Mg(OH)2 however this coating of mg(oh)2 prevent it from further reaction

 Fe react with water and form ferric hydride

3Fe +H2O.......................2 FeH +FeO

copper do not react with water

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3 years ago
The element copper has 29 protons. What is the atomic number of copper?
stiks02 [169]
The atomic number of copper is 29.

Hope this helps and if it does, don't be afraid to rate my answer as well as maybe give it a "Thanks"? (Or even better a "Brainliest"). And if it’s not correct, I am sorry for wasting your time, and good luck finding the correct answer :)


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When doing a titration what is the equivalency point of the neutralization reaction?
KengaRu [80]
The equivalency point is at the point of the titration where the amount of titrant added neutralize the solution. When it’s a strong acid strong base titration, the equivalence point will be 7. When it is a weak acid strong base, the equivalence point it more basic (the exact number depends on what acid and base you use). And when it is a strong acid weak base, the equivalence number is more acid (the exact number depends on what acid and base you use). Hope this helps!
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Foods cook faster when placed in a pressure cooker. This is because the pressure on the surface of the water is (higher than/low
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Answer:

The pressure is higher than the atmospheric one, therefore the temperature is less.

Explanation:

When it is closed permanently, the pressure of the pot inside it increases, generating that the atoms and particles of the water are closer together, increasing their kinetic energy, if intermolecular friction and therefore the boiling point is lower, because the water reaches a boil or boil at a lower temperature.

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