Ask question

Ask question

All categories

4 years ago

12

Give an example of an element that would be expected to share similar chemical properties with beryllium, calcium, and strontium

.

1 answer:

Aleks04 [339]4 years ago

4 0

Strontium possibly but I’m not 100% sure

You might be interested in

"Thermite" reactions have been used for welding metal parts such as railway rails and in metal refining. One such thermite react

frosja888 [35]

<u>Answer:</u> The given reaction is non-spontaneous in nature.

<u>Explanation:</u>

Entropy change is defined as the difference in entropy of all the product and the reactants each multiplied with their respective number of moles.

The equation used to calculate entropy change is of a reaction is:

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

For the given chemical reaction:

$3Mg(s)+Cr_2O_3(s)\rightarrow 3MgO(s)+2Cr(s)$

The equation for the entropy change of the above reaction is:

$\Delta S^o_{rxn}=[(3\times \Delta S^o_{(MgO(s))})+(2\times \Delta S^o_{(Cr(s))})]-[(3\times \Delta S^o_{(Mg(s))})+(1\times \Delta S^o_{(Cr_2O_3(s))})]$

We are given:

$\Delta S^o_{(Mg(s))}=32.68J/K.mol\\\Delta S^o_{(Cr_2O_3(s))}=81.2J/K.mol\\\Delta S^o_{(MgO(s))}=26.94J/K.mol\\\Delta S^o_{(Cr(s))}=23.77J/K.mol$

Putting values in above equation, we get:

$\Delta S^o_{rxn}=[(3\times (26.94))+(2\times (23.77))]-[(3\times (32.68))+(1\times (81.2))]\\\\\Delta S^o_{rxn}=-50.88J/K=-0.0509kJ/K.mol$

For the reaction to be spontaneous, the Gibbs free energy of the reaction must come out to be negative.

To calculate the standard Gibbs free energy of the reaction, we use the equation:

$\Delta G^o=\Delta H^o-T\Delta S^o$

where,

$\Delta G^o$ = standard Gibbs free energy = ?

$\Delta H^o$ = standard enthalpy change of the reaction = 665.1 kJ/mol

T = Temperature = 298.15 K

$\Delta S^o$ = standard entropy change of the reaction = -0.0509 kJ/K.mol

Putting values in above equation, we get:

$\Delta G^o=(665.1kJ/mol)-(298.15K\times (-0.0509kJ/K.mol))=680.27kJ/mol$

As, the Gibbs free energy of the reaction is coming out to be positive, the reaction is non-spontaneous in nature.

Hence, the given reaction is non-spontaneous in nature.

4 0

4 years ago

A spring scale is MOST useful in measuring _____.

lesantik [10]

A spring scale measures weight. some even use them to measure the weight of fish

8 0

3 years ago

Read 2 more answers

The tendency for an object at rest to remain at rest is?

cestrela7 [59]

Newtons First Law... <span>Newton's first law of motion - sometimes referred to as the law of </span>inertia<span>. An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an </span>unbalanced<span> force.</span>

6 0

4 years ago

Benzoyl peroxide, the substance most widely used against acne, has a half-life of 9.8 × 103 days when refrigerated. How long wil

prohojiy [21]

Answer:

$7.3\times 10^2\ days$

Explanation:

Given that:

Half life = $9.8\times 10^3$ days

$t_{1/2}=\frac{\ln2}{k}$

Where, k is rate constant

So,

$k=\frac{\ln2}{t_{1/2}}$

$k=\frac{\ln2}{9.8\times 10^3}\ days^{-1}$

The rate constant, k = 0.00007 days⁻¹

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

Given:

5 % is lost which means that 0.05 of $[A_0]$ is decomposed. So,

$\frac {[A_t]}{[A_0]}$ = 1 - 0.05 = 0.95

t = ?

$\frac {[A_t]}{[A_0]}=e^{-k\times t}$

$0.95=e^{-0.00007\times t}$

t = 732.76 days = $7.3\times 10^2\ days$

7 0

3 years ago

The gravitational force acting on an object is its _____.

Rasek [7]

The gravitational force acting on an object is its weight.

the answer is C.

5 0

4 years ago

Read 2 more answers