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3 years ago

Circle the letter of each sentence that is part of John Dalton’s atomic theory.

Chemistry

1 answer:

satela [25.4K]3 years ago

4 0

Answer:

A) All the elements are composed of atoms.

d) Atoms cannot be created or destroyed in any chemical changes.

c) An atom of one element cannot be changed into an atom of a different element.

Explanation:

The main postulates of Dalton atomic theory was:

1) The matter is composed of atoms and atom is indivisible particle which can not be destroyed.

2) The atoms of an element are identical.

3) The atoms of different elements are combining with definite proportion and form compounds.

4) The atoms of different elements are different from each other.

5) During chemical reaction rearrangement of atoms occur and form new compounds.

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Answer:

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Looking at the periodic table, barium is a metal. Calcium is also a metal.

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Answer: $1.0\times 10^2g$

Explanation:

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$\Delta T_f=i\times K_f\times m$

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m= molality

$\Delta T_f=i\times K_f\times \frac{\text{mass of solute}}{\text{molar mass of solute}}\times \text{weight of solvent in kg}}$

Weight of solvent (X)= 950 g = 0.95 kg

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Mass of non electrolyte (urea) added = ?

$7.2=1\times 3.96\times \frac{xg}{60.06 g/mol\times 0.95kg}$

$x=1.0\times 10^2g$

Thus $1.0\times 10^2g$ urea was dissolved.

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