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irinina [24]
3 years ago
12

How many moles of helium atoms are there in

Chemistry
1 answer:
fredd [130]3 years ago
6 0

a is the correct answer .

2.4 × 10^24

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Briefly describe how a potentiometric pHmeter works. (Hint: Describe how the pH meter measures the amount of H+ or OH- ions in a
KengaRu [80]

Answer:

Indicators show changes in the pH of a solution

Explanation:

A pH meter is an instrument that measures the hydrogen-ion activity in aqueous solutions, indicating the acidity or alkalinity of the solution expressed as pH .The pH meter measures the difference in electrical potential between a pH electrode and a reference electrode, hence the pH meter is sometimes referred to as a potentiometric pH meter. Potentiometric pH meters measure the voltage between two electrodes and display the result converted into the corresponding pH value. The instrument comprises of a simple electronic amplifier and a pair of electrodes, or alternatively a combination electrode, and some form of display calibrated in pH units. It usually has a glass electrode and a reference electrode, or a combination electrode. The electrodes, or probes, are inserted into the solution to be tested.

Organic indicators are chemical species that change their colour in response to changes in the pH of the solution. This implies that the anionic and protonated forms of the indicator possess different colours. Hence the colour changes in acidic, basic and neutral solutions. The images attached indicate the colour changes in phenolphthalein and methyl orange in acidic and basic media accordingly.

4 0
2 years ago
What is work and state the law of conservation mass?<br>​
Butoxors [25]

Answer:

Work is a force causing the movement or displacement of an object

law of conservation mass:

1. Atoms cannot be created or destroyed in a chemical reaction.

2. Molecules cannot be created or destroyed in a chemical reaction.

3. Compounds cannot be created or destroyed in a chemical reaction.

4. Heat cannot be created or destroyed in a chemical reaction.

7 0
3 years ago
Match the scientist with their achievement:
Tju [1.3M]

Answer:

<u>Frederich Miescher</u>- first person to isolate DNA and RNA

<u>Frederick Griffith</u>- first to demonstrate horizontal transmission of dna using bacteria

<u>Gregor Mendel</u>- documented and demonstrated inheritance patterns

Thomas Hunt Morgan- identified chromosomes as the structures responsible for inheritance

<u>Joachim Hammerling</u>- demonstrated that the hereditary information of of eukaryotes is contained within the nucleus

<u>Alfred Hershey and Martha Chase</u>- demonstrated that dna not protein was the molecule responsible for hereditary

<u>George Beadle and Edward Tatum</u>- used mutants to show the relationship between DNA and proteins

<u>Albrecht Kossel</u>- characterized the structure of adenine, guanine, cytosine, thymine, and uracil

Explanation:

Hope this helps! Pls give brainliest!

5 0
2 years ago
which tool was mostly likely used in a procedure if the lab report shows that approximately 300 ml of water was used
DiKsa [7]

it is most likely a beaker, beacuse 300ml is quite a large volume. Otherwise, it would be a measuring cylinder or pippette

7 0
3 years ago
Please Help me
dangina [55]
Democritus was the first to propose the idea of the atom. He said the atom was just this tiny, solid sphere. However, he used no scientific evidence to support his claim, so a guy named John Dalton did some experimenting and basically backed up Democritus' claim with evidence. Then, a guy named J.J. Thompson came along and said the atom was not solid and that is consisted of tiny negatively charged particles(electrons) and he came up with the Plum Pudding model which is just a tiny sphere with a punch of random scattered dots in it. After that, Ernest Rutherford did experiments and found that the tiny sphere is made up of mostly empty space with a tiny, dense, positively charged sphere inside of it, and the negatively charged particles just randomly float around it. Neils Bohr then said that the electrons take specific, circular, evenly spaced paths. Then, finally, we come to the Quantum Mechanical Model which is the one accepted today. This model basically vetos Bohr's idea and has a nucleus inside of an electron cloud, which is where the electrons are found.
6 0
3 years ago
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