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3 years ago

What is the difference between mass number and atomic number

2 answers:

7 0

Mass number is the number of protons and neutrons in an atom.
Atomic mass is the average mass of all the isotopes of a certain type.

myrzilka [38]3 years ago

5 0

Atomic number is the number of protons that are inside that atom. This helps identify which element an atom is.

Atomic mass is the number of protons and neutrons inside an atom.

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Balance the following chemical reaction: _NaOH + _H2SO4 ----->_Na2SO4 +_H20

Dima020 [189]

Answer:

Sodium Hydroxide + Sulfuric Acid = Sodium Sulfate + Water

2NaOH + H2SO4 → Na2SO4 + 2H2O

Explanation:

To balance a chemical equation, enter an equation of a chemical reaction and press the Balance button. The balanced equation will appear above.

Use uppercase for the first character in the element and lowercase for the second character. Examples: Fe, Au, Co, Br, C, O, N, F.

Ionic charges are not yet supported and will be ignored.

Replace immutable groups in compounds to avoid ambiguity. For example, C6H5C2H5 + O2 = C6H5OH + CO2 + H2O will not be balanced, but XC2H5 + O2 = XOH + CO2 + H2O will.

Compound states [like (s) (aq) or (g)] are not required.

You can use parenthesis () or brackets [].

8 0

3 years ago

A metal foil has a threshold frequency of 5.45 \times 10^{14} \text{ } \text{Hz}5.45Ã—10 14 Hz. Which of the colors of visible l

nalin [4]

Answer:

Green, Blue, Indigo, Violet

Explanation:

According to Einstein's equation of photoelectric effect, the kinetic energy of emitted photoelectron is the difference between the energy of the incident photon and the work function of the metal. The work function of the metal referee to the minimum energy that must be supplied in order to eject an electron from a metal surface. The energy of the incident photon must exceed the work function of the metal.

When we look at the electromagnetic spectrum, only the selected colours have frequency above the threshold frequency as shown by the image attached below.

7 0

3 years ago

Read 2 more answers

How many moles of FeCl3 could be produced from 6.1 moles of Cly? 2 Fe + 3Cl2 —> 2 FeCl2

Black_prince [1.1K]

Answer:

4.1 moles of FeCl₃

Explanation:

The reaction expression is given as shown below:

2Fe + 3Cl₂ → 2FeCl₃

Number of moles of Cl₂ = 6.1moles

So;

We know that from the balanced reaction expression:

3 moles of Cl₂ will produce 2 moles of FeCl₃

Therefore 6.1moles of Cl₂ will produce $\frac{6.1 x 2}{3}$ = 4.1 moles of FeCl₃

The number of moles is 4.1 moles of FeCl₃

6 0

3 years ago

Why doesnt science offer conclusive proof of phenomena

Rashid [163]

Evidence could be gathered in the future that contradicts original theories. Phenomena cannot be proven by conclusive evidence in science because, as of now, the evidence isn't conclusive. It is speculation. Just as a phenomena cannot be proven, it also cannot be disproven.

3 0

3 years ago

Which of these half-reactions represents reduction?

gogolik [260]

Answer: The half-reactions represents reduction are as follows.

$Cr_{2}O^{2-}_{7} \rightarrow Cr^{3+}$
$MnO^{-}_{4} \rightarrow Mn^{2+}$

Explanation:

A half-reaction where addition of electrons take place or a reaction where decrease in oxidation state of an element takes place is called reduction-half reaction.

For example, the oxidation state of Cr in $Cr_{2}O^{2-}_{7}$ is +6 which is getting converted into +3, that is, decrease in oxidation state is taking place as follows.

$Cr_{2}O^{2-}_{7} + 3 e^{-} \rightarrow Cr^{3+}$

Similarly, oxidation state of Mn in $MnO^{-}_{4}$ is +7 which is getting converted into +2, that is, decrease in oxidation state is taking place as follows.

$MnO^{2-}_{4} + 5 e^{-} \rightarrow Mn^{2+}$

Thus, we can conclude that half-reactions represents reduction are as follows.

$Cr_{2}O^{2-}_{7} \rightarrow Cr^{3+}$
$MnO^{-}_{4} \rightarrow Mn^{2+}$

3 0

3 years ago