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3 years ago

Name the type of equation shown here:

Chemistry

2 answers:

Misha Larkins [42]3 years ago

7 0

Double replacement I think

jeka943 years ago

3 0

Answer: B. single replacement

Explanation:

1. Double displacement reaction is one in which exchange of ions take place.

Example: $2NaOH(aq)+(NH_4)_2SO_4(aq)\rightarrow 2NH_4OH(aq)+Na_2SO_4(aq)$

2. Single replacement reaction is a chemical reaction in which more reactive element displaces the less reactive element from its salt solution.

Example: $3Pb+2H_3PO_4\rightarrow 3H_2+Pb_3(PO_4)_2$

3. Combustion is a type of chemical reaction in which fuel is reacted with oxygen to form carbon dioxide and water.

Example:

$C_6H_{12}O_6+O_2 \rightarrow CO_2+H_2O$

4. Synthesis reaction is a chemical reaction in which two reactants are combining to form one product.

Example: $Li_2O+CO_2\rightarrow Li_2CO_3$

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Check all items common to bases. minerals metal gas H+ OH- nitrogen

Darya [45]

OH- is common to bases.

Explanation:

The base is a is an ionic compounds which when placed in aqueous solution dissociates in to a cation and an anion OH-.

The presence of OH- in the solution shows that the solution is basic or alkaline.

From Bronsted and Lowry concept base is a molecule that accepts a proton for example in NaOH, Na is a proton donor and OH is the proton acceptor.

A base accepts hydrogen ion and the concentration of OH is always higher in base.

There is a presence of conjugate acid and conjugate base in the Bronsted and Lowry acid and base.

Conjugate acid is one which is formed when a base gained a proton.

Conjugate base is one which is formed when an acid looses a proton.

And from the Arrhenius base Theory, the base is one that dissociates in to water as OH-.

8 0

3 years ago

The unit cell for cr2o3 has hexagonal symmetry with lattice parameters a = 0.4961 nm and c = 1.360 nm. If the density of this ma

IRINA_888 [86]

To calculate the packing factor, first calculate the area and volume of unit cell.

Area is calculated as:

$A=6R^{2}\sqrt{3}$

Here, R is radius and is related to a as follows:

$R=\frac{a}{2}$

Putting the value in expression for area,

$A=6(\frac{a}{2})^{2}\sqrt{3}=1.5a^{2}\sqrt{3}$

The value of a is 0.4961 nm

Since, $1 nm=10^{-7}cm$

Thus, $0.4961 nm=4.961\times 10^{-8} cm$

Putting the value,

$Area=1.5(4.961\times 10^{-8}cm)^{2}\sqrt{3}=6.39\times 10^{-15}cm^{2}$

Now, volume can be calculated as follows:

$V=Area\times c$

The value of c is 1.360 nm or $1.360\times 10^{-7} cm$

Putting the value,

$V=(6.39\times 10^{-15}cm^{2})\times (1.360\times 10^{-7} cm)=8.7\times 10^{-22}cm^{3}$

now, number of atom in unit cell can be calculated by using the following formula:

$n=\frac{\rho N_{A}V_{c}}{A}$

Here, A is atomic mass of $Cr_{2}O_{3}$ is 151.99 g/mol.

Putting all the values,

$n=\frac{(5.22 g/cm^{3})(6.023\times 10^{23} mol^{-1})(8.7\times 10^{-22}cm^{3})}{(151.99 g/mol)}\approx 18$

Thus, there will be 18 $Cr_{2}O_{3}$ units in 1 unit cell.

Since, there are 2 Cr atoms and 3 oxygen atoms thus, units of chromium and oxygen will be 2×18=36 and 3×18=54 respectively.

The atomic radii of $Cr^{3+}$ and $O^{2-}$ is 62 pm and 140 pm respectively.

Converting them into cm:

$1 pm=10^{-10}cm$

Thus,

$r_{Cr^{3+}}=6.2\times 10^{-9}cm$

and,

$r_{O^{2-}}=1.4\times 10^{-8}cm$

Volume of sphere will be sum of volume of total number of cations and anions thus,

$V_{S}=V_{Cr^{3+}}+V_{O^{2-}}$

Since, volume of sphere is $V=\frac{4}{3}\pi r^{3}$ ,

$V_{S}=36\left ( \frac{4}{3}\pi (r_{Cr^{3+})^{3}} \right )+54\left ( \frac{4}{3}\pi (r_{O^{2-})^{3}} \right )$

Putting the values,

$V_{S}=36\left ( \frac{4}{3}(3.14) (6.2\times 10^{-9} cm)^{3}} \right )+54\left ( \frac{4}{3}(3.14) (1.4\times 10^{-8} cm)^{3}} \right )=6.6\times 10^{-22}\times 10^{-8}cm^{3}$

The atomic packing factor is ratio of volume of sphere and volume of crystal, thus,

$packing factor=\frac{V_{S}}{V_{C}}=\frac{6.6\times 10^{-22}cm^{3}}{8.7\times 10^{-22}cm^{3}}=0.758$

Thus, atomic packing factor is 0.758.

6 0

3 years ago

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Which of the following statements is a true statement regarding a solution with [H1+] =1x10-5 M and [OH1-]= 1x10-9 M?

zheka24 [161]

Answer:

B. The [H1+] >[OH1-] and the solution is acidic

4 0

3 years ago

Kinetic energy is energy of motion. What below is considered to be a form of kinetic energy?

gregori [183]

Answer:

In physics, the kinetic energy of an object is the energy that it possesses due to its motion It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity Having gained this energy during its acceleration the body maintains this kinetic energy unless its speed changes

Example:

A semi-truck travelling down the road

A river flowing at a certain speed

5 0

3 years ago

Which is the larger quantity 1.0 km or 1.0 mi

Norma-Jean [14]

A mile.

For reference, it's about 1,607 or so meters, and 1km is 1,000.

4 0

3 years ago

Read 2 more answers