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2 years ago

Which of the following statements is/are correct?

Chemistry

1 answer:

-Dominant- [34]2 years ago

3 0

Answer:

The correct statement is;

(B) Only II

Explanation:

I) The atomic mass unit or amu which is also known as daltons which is defined as 1/12 × the mass of a carbon-12 atom, which is therefore, 1.660538921 × ⁻²⁴ grams

Therefore, the mass of 1 atom of carbon-12 = 12 amu

II) The mass of one mole of oxygen-16 is 16 grams while the mass of one mole of carbon-12 is 12 grams

The mass of 4 atoms of carbon 12 = 4 × 12 amu = 48 amu

The mass of 1 atom of oxygen-16 = 15.99491461956 amu

Therefore, the mass of 3 atoms of oxygen-16 = 3 × 15.99491461956 = 47.9847438587 amu ≈ 48 amu

Therefore only II is correct.

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BaCl2(aq) + Na2CO3(aq) BaCO3(s) + NaCl(aq

Vitek1552 [10]

This is the equation balanced:

BaCl2(aq) + Na2CO3(aq) = BaCO3(s) + 2 NaCl(aq)

Then the coefficient in front of Na Cl is 2.

Answer: 2

7 0

3 years ago

A 9.79 mol sample of freon gas was placed in a balloon. Adding 3.50 mol of freon gas to the balloon increased its volume to 21.8

aivan3 [116]

Answer:

16.06 L was the initial volume of the balloon.

Explanation:

Initial moles of freon in ballon = $n_1=9.79 mol$

Initial volume of freon gas in ballon = $V_1=?$

Moles of freon gas added in the balloon = n = 3.50 mole

Final moles of freon in ballon = $n_2=n_1+n=9.79 mol+3.50 mol=13.29 mol$

Final volume of freon gas in ballon = $V_2=21.8 L$

Using Avogadro's law:

$\frac{V_1}{n_1}=\frac{V_2}{n_2}$ ( at constant pressure and temperature)

$V_1=\frac{V_2\times n_1}{n_2}=\frac{21.8 L\times 9.79 mol}{13.29 mol}=16.06L$

16.06 L was the initial volume of the balloon.

4 0

2 years ago

A precipitate forms when mixing solutions of sodium fluoride (NaF) and lead II nitrate (Pb(NO3)2). Complete and balance the net

Leya [2.2K]

Answer:

See explanation

Explanation:

The molecular equation shows all the compounds involved in the reaction.

The molecular equation is as follows;

2NaF(aq) + Pb(NO3)2(aq) -------> PbF2(s) + 2NaNO3(aq)

The complete ionic equation shows all the ions involved in the reaction

The complete ionic equation;

2Na^+(aq) + 2F^-(aq) + Pb^2+(aq) + 2NO3^-(aq) -------->PbF(s) + 2Na^+(aq) +2NO3^-(aq)

The net Ionic equation shows the ions that actually participated in the reaction

The net ionic equation is;

2F^-(aq) + Pb^2+(aq)--------> PbF(s)

3 0

2 years ago

Which of the following statements correctly describe metalloids?

BlackZzzverrR [31]

Metalloids are elements that have both metal and nonmetal properties

3 0

3 years ago

Determine the formula of chromic acid.

Katyanochek1 [597]

Answer: The formula of chromic acid is $H_2CrO_4$

Explanation:

We are given an ionic compound named as chromic acid. This acid is formed by the combination of hydrogen ion and chromate ion.

An acid is defined as the substance which releases hydrogen ion when dissolved in water.

Hydrogen is the 1st element of periodic table having electronic configuration of $1s^1$ .

This element will loose 1 electron to form $H^{+}$ ion.

Chromate ion is a polyatomic ion having chemical formula of $CrO_4^{2-}$

By criss-cross method, the oxidation state of the ions gets exchanged and they form the subscripts of the other ions. This results in the formation of a neutral compound.

So, the chemical formula for the given compound is $H_2CrO_4$

Thus, the formula of chromic acid is $H_2CrO_4$

8 0

2 years ago