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3 years ago

In 4/2HE, what does the number 4 indicate?

Chemistry

1 answer:

11Alexandr11 [23.1K]3 years ago

6 0

The number 4 in the 4/2He indicates the atomic mass number of helium.

Answer: Option 3

Explanation:

The elements present in periodic table generally represented as $X_{Z}^{A}$ . Here X will be the element in the periodic table, A is the atomic mass number of the element X and Z is the atomic number of the element X.

So, the number 4 is the atomic mass number of He and He-4 is the stable isotope of helium which can also be termed as alpha particle.

Mass number = number of protons + neutrons count.

Thus the number 4 denotes the Helium's atomic mass number.

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Need help with this

choli [55]

Answer:

H20is water andN20is nitrogen 4 oxide

6 0

3 years ago

A new grill has a mass of 30.0 kg. you put 1.5 kg of charcoal in the grill. you burn all the charcoal and the grill has a mass o

atroni [7]

The reaction for burning of charcoal or complete combustion is as follows:

$C(s)+O_{2}(g)\rightarrow CO_{2}(g)$

From the above balanced reaction, 1 mole of carbon releases 1 mole of $CO_{2}$ gas.

Converting mass of charcoal into moles as follows:

$n=\frac{m}{M}$

Molar mass of pure carbon is 12 g/mol thus,

$n=\frac{1.5\times 10^{3} g}{12 g/mol}=125mol$

The same moles of $CO_{2}$ is released. Converting these moles into mass as follows:

m=n×M

Molar mass of $CO_{2}$ is 44 g/mol thus,

$m=125mol\times 44 g/mol=5.5\times 10^{3}g$

Converting mass into kg,

$1g=10^{-3}kg$

Thus, total mass of gas released is 5.5 kg.

7 0

3 years ago

A bucket of water contains 5.45 L of water, how many mL of water is this ?

nalin [4]

Answer: It is 5450 mL

Explanation: There are 1000 mL in every L and then there is an extra 450 so just add that at the end

6 0

3 years ago

what is the diffrence between displacement ans double displacement reactions write equations for these reactions

Lina20 [59]

Answer:

Single Displacement reaction

In a displacement reaction, a more reactive element replaces a less reactive element from a compound.

Change in colour takes place with no precipitate forms.

Metals react with the salt solution of another metal.

Examples:

2KI + Cl2 → 2KCl + I2

CuSO4 + Zn → ZnSO4 + Cu

Double displacement reaction

In a double displacement reaction, two atoms or a group of atoms switch places to form new compounds.

Precipitate is formed.

Salt solutions of two different metals react with each other.

Examples:

Na2SO4 + BaCl2 → BaSO4 + 2NaCl

2KBr + BaCl2 → 2KCl + BaBr2

Hope this helps...Please Mark as Brainliest!!

8 0

3 years ago

Please help me, I really don't want to fail but I don't know how to do this

Brrunno [24]

Answer:

4, 7, 4, 6

12 moles

Explanation:

$NH_{3}(g) + O_{2}(g) \: → NO_{2} + H_{2}O(g)$

__↑______↑

8.00 mol | 14.00 mol

________________

$NH_{3}(g) + O_{2}(g) \: → NO_{2} + H_{2}O(g)$

You can turn this into a system of variables which are solvable.

To do this, create variables for the coefficients of each compound in the reaction respectively.

$a(NH_{3}(g)) + b(O_{2}(g)) → \\c(NO_{2}) + d(H_{2}O(g))$

Because to be balanced, the count of atoms in each element of the compound correspond to the coefficient of the variable in that compound so that the count of the left (reactant) side is set equal to the right (product) side.

a corresponds to the coefficient of the first compound, b corresponds to the coefficient of the second compound, c corresponds to the coefficient of the third compound, and d corresponds to the coefficient of the fourth compound.

(Reactant = Product)

Reactant: 1a [N] Product: 1c.

Reactant: 3a [H] Product: 2d.

Reactant: 2b [O] Product: 2c + 1d.

Thus the system is:

1a = 1c

3a = 2d

2b = 2c + 1d.

Then just use the substitution methods to solve.

3 0

2 years ago