All categories

3 years ago

List three types of physical evidence that indicate a chemical reaction has occurred

Chemistry

1 answer:

Anarel [89]3 years ago

7 0

Answer:

Formation of a precipitate
Color change
Change in temperature

Explanation:

The reactions may be accompanied by evidence of a change in some physical property, which can be observed with the eye or with suitable measuring instruments.

You might be interested in

What is the mass of .89 moles of lithium metal, used in laptop batteries?

Elza [17]

6.17749 would be the mass

3 0

3 years ago

Consider the decomposition of a metal oxide to its elements, where M represents a generic metal.

VladimirAG [237]

Answer:

For 1: The standard Gibbs free energy change of the reaction is 10.60 kJ/mol

For 2: The equilibrium constant for the given reaction at 298 K is $1.386\times 10^{-2}$

For 3: The equilibrium pressure of oxygen gas is 0.0577 atm

Explanation:

For 1:

The equation used to calculate standard Gibbs free energy change of a reaction is:

$\Delta G^o_{rxn}=\sum [n\times \Delta G^o_f_{(product)}]-\sum [n\times \Delta G^o_f_{(reactant)}]$

For the given chemical reaction:

$M_2O_3(s)\rightarrow 2M(s)+\frac{3}{2}O_2(g)$

The equation for the standard Gibbs free energy change of the above reaction is:

$\Delta G^o_{rxn}=[(2\times \Delta G^o_f_{(M(s))})+(\frac{3}{2}\times \Delta G^o_f_{(O_2(g))})]-[(1\times \Delta G^o_f_{(M_2O_3(s))})]$

We are given:

$\Delta G^o_f_{(M_2O_3(s))}=-10.60kJ/mol\\\Delta G^o_f_{(M(s))}=0kJ/mol\\\Delta G^o_f_{(O_2(g))}=0kJ/mol$

Putting values in above equation, we get:

$\Delta G^o_{rxn}=[(2\times (0))+(\frac{3}{2}\times (0))]-[(1\times (-10.60))]\\\\\Delta G^o_{rxn}=10.60kJ/mol$

Hence, the standard Gibbs free energy change of the reaction is 10.60 kJ/mol

For 2:

Relation between standard Gibbs free energy and equilibrium constant follows:

$\Delta G^o=-RT\ln K_{eq}$

where,

$\Delta G^o$ = Standard Gibbs free energy = 10.60 kJ/mol = 10600 J/mol (Conversion factor: 1 kJ = 1000 J )

R = Gas constant = 8.314 J/K mol

T = temperature = 298 K

$K_{eq}$ = equilibrium constant = ?

Putting values in above equation, we get:

$10600J/mol=-(8.314J/Kmol)\times 298K\times \ln (K_{eq})\\\\K_{eq}=1.386\times 10^{-2}$

Hence, the equilibrium constant for the given reaction at 298 K is $1.386\times 10^{-2}$

For 3:

The expression of $K_{eq}$ for above equation follows:

$K_{eq}=p_{O_2}^{3/2}$

The concentration of pure solids and pure liquids are taken as 1 in the expression. That is why, the concentration of metal and metal oxide is taken as 1 in the expression.

Putting values in above expression, we get:

$1.386\times 10^{-2}=p_{O_2}^{3/2}\\\\p_{O_2}=0.0577atm$

Hence, the equilibrium pressure of oxygen gas is 0.0577 atm

6 0

3 years ago

What happens when current flows through a wire?

Serhud [2]

Answer: Two effects may occur during high current flow: 1) the wire may become overheated to the point that surface oxidation or even evaporation may take place, 2) at the connection points at each end of the wire, especially if the terminations are of a different type of metal than the wire, some atoms may migrate into or out of the wire.

8 0

3 years ago

The names of the components FeS, NaCl, and Al(3)O(2) all end in the suffix.

anastassius [24]

Answer:

A) -ide

Explanation:

FeS = iron(II) sulfide or ferrous sulfide

NaCl = Sodium chloride

Al(3)O(2) = Aluminium oxide

3 0

3 years ago

3. what is the relationship between a coefficient; chemical formula

Novosadov [1.4K]

The coefficient in a chemical formula represents the amount of each chemical present. The amount of a substance is measured in moles.

4 0

3 years ago