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2 years ago

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

Chemistry

1 answer:

satela [25.4K]2 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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The mass spectrum of an unknown compound has a molecular ion peak with a relative intensity of 57.10% and an M+1 peak of 6.83%.

max2010maxim [7]

There are 11 Carbon atoms in the compound.

<u>Solution:</u>

Carbon atom count is the ratio of the M peak to the M+1 peak.

$\text{ Number of Carbon atoms }=\frac{\text { Relative intensity of } M+1 \text { peak }}{0.011 \times \text { Relative tntensity of } M \text { peak }}$

Here M peak is 57.10% and M+1 peak is 6.83%. On applying the values in the formula we get,

$\frac{0.0683}{0.011\times0.571g} = 10.87\approx11$

Therefore, the number of Carbon atoms in the compound are 11.

Refer the image attached below for a better understanding of M peak and M+1 peak.

The heaviest ion that has the greatest m/z value is said to be the molecular ion peak in mass spectrum.

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3 years ago

The melting point of table salt is 801 degrees celsius. is this a physical or chemical property?

Valentin [98]

It is a Physical property because like water it changes into a ice cube but it can be melted into water or be turned back into an ice cube.

5 0

2 years ago

45.7 grams of calcium chloride reacts with an excess of aluminum oxide. How many grams of aluminum chloride will be produced

damaskus [11]

Molar mass (CaCl2) = 40.1 +2*35.5 = 111.1 g/mol
Molar mass (AlCl3) = 27.0 +3*35.5= 133.5 g/ mol

3CaCl2+Al2O3 -------->3CaO +2AlCl3
mole from reaction 3 mol 2 mol
mass from reaction 3mol* 111.1g/mol 2 mol*133.5g/mol
333.3 g 267.0 g
mass from problem 45.7 g x g

Proportion:
333.3 g CaCl2 ------- 267.0 g AlCl3
45.7 g CaCl2 -------- x g AlCl3

x=45.7*267.0/333.3= 36.6 g AlCl3

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3 years ago

Klklklkllkllklkklkllkl

Svetradugi [14.3K]

Answer:

klklklkllkllklkklkllkl

Explanation:

Cuz thats what you said.. and why not :)

5 0

2 years ago

2. What ions are present in what ratio in a solution of aqueous calcium chloride?

Alenkasestr [34]

Answer:

$\mathrm{Ca}^{2+} \text { and } \mathrm{Cl} \text { - ions are present in } 1: 2 \text { ratio in a solution of aqueous calcium chloride. }$

Explanation:

Here in Calcium Chloride ionic bond is present in between calcium and chlorine atoms. As we know according to Octet rule calcium have two excess atoms and for matching nearest noble gas electronic configuration. It donate two electrons to gain more stability and form $\mathrm{Ca}^{2+}$ , while chlorine is deficient from one electron to meet nearest noble gas electronic configuration therefore two chlorine atoms accept excess electron from calcium individually and form two $\mathrm{Cl}^{-}$ ions.

$\text { Equation is as follows: } \mathrm{Ca}^{2+}+2 \mathrm{Cl}^{-} \rightarrow \mathrm{CaCl}_{2}$

Hence aqueous solution of calcium chloride breaks the ionic bond pairing in one $\mathrm{Ca}^{2+}$ and two $\mathrm{Cl}^{-}$ ions: $\mathrm{CaCl}_{2} \longrightarrow \mathrm{H}_{2} \mathrm{O} \quad \mathrm{Ca}^{2+}(\mathrm{ag})+2 \mathrm{Cl}(\mathrm{ag})$

5 0

3 years ago