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3 years ago

1. Calculate the molarity of 35g of calcium chloride (CaCl2) that is dissolved in 850ml of water. (Calculate moles first)

Chemistry

1 answer:

erastovalidia [21]3 years ago

6 0

Answer:

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1 . a chemical bond formed by the electrostatic attraction between ions covalent bond

liberstina [14]

Explanation:

When there occurs sharing of electrons between two chemically combining atoms then it forms a covalent bond. Generally, a covalent bond is formed between two non-metals.

An ionic bond is defined as the bond formed due to transfer of one or more number of electrons from one atom to another. An ionic bond is always formed between a metal and a non-metal.

Every atom of an element will have orbitals in which electrons are found. These orbitals are known as energy level.

A molecule is defined as the smallest particle present in a substance or atom.

A metallic bond is formed due to mobile valence electrons shared by positive nuclei in a metallic crystal.

Thus, we can conclude that given statements are correctly matched as follows.

1). a chemical bond formed by the electrostatic attraction between ions - ionic bond

2). a chemical bond formed by two electrons that are shared between two atoms - covalent bond

3). the orbitals of an atom where electrons are found - energy level

4). the smallest particle of a covalently bonded substance - molecule

5). a bond characteristic of metals in which mobile valence electrons are shared among positive nuclei in the metallic crystal - metallic bond

7 0

3 years ago

Given the reaction: solid sodium reacts with chlorine gas to form solid sodium chloride How many moles of the product result fro

lyudmila [28]

Answer:

number of moles of NaCl produce = 12 mol

Explanation:

Firstly, we need to write the chemical equation of the reaction and balance it .

Na(s) + Cl2(g) → NaCl(s)

The balanced equation is as follows:

2Na(s) + Cl2(g) → 2NaCl(s)

1 mole(71 g) of chlorine produces 2 moles(117 g) of sodium chloride

6 mole of chlorine gas will produce ? mole of sodium chloride

cross multiply

number of moles of NaCl produce = 6 × 2

number of moles of NaCl produce = 12 moles

number of moles of NaCl produce = 12 mol

3 0

3 years ago

Hi everyone how is your guys day huh I believe good right

Kisachek [45]

H, my day has been alright, how’s yours?

7 0

3 years ago

Excess magnesium reacts with 165.0 grams of hydrochloric acid in a single displacement reaction.

JulsSmile [24]

Answer:

The volume of hydrogen gas produced will be approximately 50.7 liters under STP.

Explanation:

Relative atomic mass data from a modern periodic table:

H: 1.008;
Cl: 35.45.

Magnesium is a reactive metal. It reacts with hydrochloric acid to produce

Hydrogen gas $\rm H_2$ , and
Magnesium chloride, which is a salt.

The chemical equation will be something like

$\rm ?\;Mg\;(s) + ?\;HCl \;(aq)\to ?\;H_2 \;(g)+ [\text{Formula of the Salt}]$ ,

where the coefficients and the formula of the salt are to be found.

To determine the number of moles of $\rm H_2$ that will be produced, first find the formula of the salt, magnesium chloride.

Magnesium is a group 2 metal. The oxidation state of magnesium in compounds tends to be +2.

On the other hand, the charge on each chloride ion is -1. Each magnesium ion needs to pair up with two chloride ions for the charge to balance in the salt, magnesium chloride. The formula for the salt will be $\rm MgCl_2$ .

$\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ ?\;MgCl_2\;(aq)$ .

Balance the equation. $\rm MgCl_2$ contains the largest number of atoms among all species in this reaction. Start by setting its coefficient to 1.

$\rm ?\;Mg\;(s) + ?\;HCl\;(aq) \to ?\;H_2 \;(g)+ {\bf 1\;MgCl_2}\;(aq)$ .

The number of $\rm Mg$ and $\rm Cl$ atoms shall be the same on both sides. Therefore

$\rm {\bf 1\;Mg}\;(s) + {\bf 2\;HCl}\;(aq) \to ?\;H_2 \;(g)+ {1\;\underset{\wedge}{Mg}\underset{\wedge}{Cl_2}}\;(aq)$ .

The number of $\rm H$ atoms shall also conserve. Hence the equation:

$\rm {1\;Mg}\;(s) + {2\;\underset{\wedge}{H}Cl}\;(aq) \to {\bf 1\;H_2 \;(g)}+ {1\;MgCl_2}\;(aq)$ .

How many moles of HCl are available?

$M(\rm HCl) = 1.008 + 35.45 = 36.458\;g\cdot mol^{-1}$ .

$\displaystyle n({\rm HCl}) = \frac{m(\text{HCl})}{M(\text{HCl})} = \rm \frac{165.0\;g}{36.458\;g\cdot mol^{-1}} = 4.52576\;mol$ .

How many moles of Hydrogen gas will be produced?

Refer to the balanced chemical equation, the coefficient in front of $\rm HCl$ is 2 while the coefficient in front of $\rm H_2$ is 1. In other words, it will take two moles of $\rm HCl$ to produce one mole of $\rm H_2$ . $\rm 4.52576\;mol$ of $\rm HCl$ will produce only one half as much $\rm H_2$ .

Alternatively, consider the ratio between the coefficient in front of $\rm H_2$ and $\rm HCl$ is:

$\displaystyle \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}$ .

$\displaystyle n(\text{H}_2) = n(\text{HCl})\cdot \frac{n(\text{H}_2)}{n(\text{HCl})} = \frac{1}{2}\;n(\text{HCl}) = \rm \frac{1}{2}\times 4.52576\;mol = 2.26288\;mol$ .

What will be the volume of that many hydrogen gas?

One mole of an ideal gas occupies a volume of 22.4 liters under STP (where the pressure is 1 atm.) On certain textbook where STP is defined as $\rm 1.00\times 10^{5}\;Pa$ , that volume will be 22.7 liters.

$V(\text{H}_2) = \rm 2.26288\;mol\times 22.4\;L\cdot mol^{-1} = 50.69\; L$ , or

$V(\text{H}_2) = \rm 2.26288\;mol\times 22.7\;L\cdot mol^{-1} = 51.37\; L$ .

The value "165.0 grams" from the question comes with four significant figures. Keep more significant figures than that in calculations. Round the final result to four significant figures.

5 0

3 years ago

A volume of 125 mL of H2O is initially at room temperature (22.00 ∘C). A chilled steel rod at 2.00 ∘C is placed in the water. If

VMariaS [17]

Answer:

41.9 g

Explanation:

We can calculate the heat released by the water and the heat absorbed by the steel rod using the following expression.

Q = c × m × ΔT

where,

c: specific heat capacity

m: mass

ΔT: change in temperature

If we consider the density of water is 1.00 g/mol, the mass of water is 125 g.

According to the law of conservation of energy, the sum of the heat released by the water (Qw) and the heat absorbed by the steel (Qs) is zero.

Qw + Qs = 0

Qw = -Qs

cw × mw × ΔTw = -cs × ms × ΔTs

(4.18 J/g.°C) × 125 g × (21.30°C-22.00°C) = -(0.452J/g.°C) × ms × (21.30°C-2.00°C)

ms = 41.9 g

3 0

3 years ago