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anygoal [31]
3 years ago
14

What is the atomic mass for Helium (He)? Question 5 options: 8 2 3 4

Chemistry
1 answer:
Irina18 [472]3 years ago
3 0
It is 2 because if you have a chart that shown all the elements at the top left corner it would show a number and that is the atomic number
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Pls help me here, thanks in advance
Marat540 [252]

Answer:

What's the problem???

4 0
2 years ago
Read 2 more answers
How do atomic and molecular interactions explain the properties of matter that we see and feel
Licemer1 [7]

Answer:they change

Explanation:

just because

8 0
2 years ago
Explain why heat is often used in a laboratory experiment. a. To warm up the laboratory, b. To speed up a reaction
uysha [10]

Answer:

To speed up a reaction

Explanation:

Heat, as well as catalysts, increase the reaction rate of some chemical reactions since they cause the enzymes or reagents in charge of carrying out the transformation to products to act faster and increase their kinetic energy of reaction.

3 0
3 years ago
In a reaction A+B--->C, reactant A has 5g of product C has 9g of product. How many grams should reactant B contain?
Rzqust [24]

According to the law of conservation of Mass:

In a chemical reaction mass can neither be created nor be destroyed

So, we can say that: Mass of A + Mass of B = Mass of C

In the given reaction,

One of the reactants weigh 5 grams and another one weighs x grams

The mass of the product of this reaction is 9 grams

<u>Mass of reactant B:</u>

Mass of A + Mass of B = Mass of C

5 + x = 9

x = 4 grams

5 0
3 years ago
A thermally isolated system is made up of a hot piece of aluminum and a cold piece of copper; the aluminum and the copper are in
Illusion [34]

Answer:

  • <u>Copper</u><em> is the object that experiences the greater temperature change.</em>

Explanation:

<em>Thermally isolated system </em>means that the system does not exchange thermal energy with the surroundings.

Hence, any thermal exchange, in virtue of the temperature difference of the aluminum and copper pieces, is between them.

In consequence, the law of conservation of energy states that the heat lost by the hot substance will be gained by the cold matter.

In equations, that is:

  • Heat lost by aluminum = heat gained by copper.

Now, the gain or loss or heat of a substance, Q, is related with the mass (m), the specific heat (Cs), and the cahnge of temperature (ΔT), per the equation:

  • Q = m × Cs × ΔT

∴ Q lost by aluminum = Q  gained copper ⇒

  • [m × Cs × ΔT ] aluminum = [m × Cs × ΔT ] copper.

Under the reasoning assumption that the masses of aluminum and copper are equal, the equations is simplified to:

  • [Cs × ΔT ] aluminum = [Cs × ΔT ] copper.

  • Cs aluminum / Cs copper = ΔT copper / ΔT aluminum

  • Cs aluminum > 2 × Cs copper  ⇒ Cs

  • Cs aluminum / Cs copper > 2 ΔT copper / ΔT aluminum

  • ΔT copper / ΔT aluminum > 2

  • ΔT copper > 2 × ΔT aluminum

In words, since it is stated that  the specific heat of aluminum is more than double that of copper,  in order to keep the equality, ΔT of copper shall be more than double ΔT of aluminum.

Hence, the <u>conclusion</u> is that the object that experiences the greater temperature change is copper (the one with the lower specific heat), under the assumption that both objects have the same amount of matter (mass).

6 0
3 years ago
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