All categories

3 years ago

What group of elements is most likely to contain elements that will be found free in nature?

Chemistry

2 answers:

damaskus [11]3 years ago

7 0

It is either metals or non metals. but i would go for mtals

cricket20 [7]3 years ago

6 0

Answer:

This question is incomplete but the completed question is found below

What group of elements is most likely to contain elements that will be found free in nature? (a) strong metals (b) transition metals (c) nonmetals (d) noble gases.

The correct option is (d)

Explanation:

Noble gases are found free in nature because they have low reactivity. This is because they have a fully filled outermost shell and hence have little tendency to donate or share electrons hence they do not partake in chemical bonding. It is due to these reasons they exist free in nature as monoatomic gases without been bonded to another element.

Other options provided are wrong because strong metals, transition metals and non-metals have a partially filled outermost shell and hence readily bond with other elements. These causes these group of elements to be found in there combined state (with other elements or same elements) in nature.

You might be interested in

Commercial cold packs often contain solid NH4NO3 and a pouch of water. The temperature of the pack drops as the NH4NO3 dissolves

Yanka [14]

Answer: b. $\Delta H_{soln}$ is positive and $\Delta S_{soln}$ is positive.

Explanation:-

As the temperature of the pack drops, the energy has been absorbed from the pack for dissolution of $NH_4NO_3$ in water. Thus as the energy has been absorbed in the reaction, the reaction is endothermic and the change in enthalpy i.e. $\Delta H_{soln}$ is positive.

The entropy is the measure of degree of randomness. The entropy increases when the randomness increases and the entropy decreases when the randomness decreases. When a substance dissolves in water, it dissociate into ions and hence the randomness increases thus the change in entropy i.e. $\Delta S_{soln}$ is positive.

$NH_4NO_3\rightarrow NH_4^++NO_3^-$

7 0

3 years ago

If 156 grams of chromium react with an excess of oxygen, as shown in the balanced chemical equation below, how many grams of chr

Sunny_sXe [5.5K]

Answer:

=759.95 grams.

Explanation:

The molar mass of chromium is 51.9961 g/mol

Therefore the number of moles of chromium in 156 grams is:

Number of moles =mass/RAM

=156g/51.9961g/mol

=3 moles.

From the equation provided, 3 moles of chromium metal produce 2 moles of Chromium oxide.

Therefore 3 moles of chromium produce:

(3×2)/4 moles =1.5 moles of chromium oxide.

I mole of chromium oxide has a mass of 151.99 g

Thus 1.5 moles= 1.5mole ×151.99 g/mol

=759.95 grams.

3 0

3 years ago

The combustion of ethene in the presence of excess oxygen yields carbon dioxide and water: c2h4 (g) + 3o2 (g) → 2co2 (g) + 2h2o

meriva

Answer:

$\boxed{-267.5}$

Explanation:

You can calculate the entropy change of a reaction by using the standard molar entropies of reactants and products.

The formula is

$\Delta_{r} S^{\circ} = \sum_n {nS_{\text{products}}^{\circ} - \sum_{m} {mS_{\text{reactants}}^{\circ}}}$

The equation for the reaction is

C₂H₄(g) + 3O₂(g) ⟶ 2CO₂(g) + 2H₂O(ℓ)

ΔS°/J·K⁻¹mol⁻¹ 219.5 205.0 213.6 69.9

$\Delta_{r} S^{\circ} = (2\times213.6 + 2\times69.9) - (1\times219.5 + 3\times205.0)\\\\= 567.0 - 834.5 = \boxed{-267.5 \text{ J}\cdot\text{K}^{-1} \text{mol}^{-1}}$

3 0

3 years ago

What is the mole ratio needed to determine the mass of phosphorus trifluoride produced from the reaction of 120 g of phosphorus

Vitek1552 [10]

Answer:

$\frac{4molPF_3}{1molP_4}$

Explanation:

Hello

In this case, given the reaction:

$P_4(s)+6F_2(g)\rightarrow 4PF_3(g)$

It means that since the coefficients preceding phosphorous and phosphorous trifluoride are 1 and 4, the correct mole ratio should be:

$\frac{4molPF_3}{1molP_4}$

Because given the mass of phosphorous it is convenient to convert it to moles and then cancel it out with the moles on bottom of the mole ratio.

Bes regards!

8 0

3 years ago

How many grams of NH3 are needed to provide the same number of molecules as in 0.85 grams of SF6?

solniwko [45]

Above it says the molecular weights are

NH3- 17g/mol and SF6-146 g/mol

Well 1 mole of SF6 is 146.048 grams (i added hte atomic masses of each element). So then the number of moles in 0.85 grams would be 0.00582000438 moles.

= 1mole / 146.048g * 0.85g

so we would need 0.00582000438 moles of NH3 to have the same number of molecules.

One mole of NH3 is 17.030519999989988 grams (i added each atoms mass). so 0.00582000438 moles of NH3 would be:

= 17.030519999989988 g / mole * 0.00582000438moles

that equals 0.09911770099 grams.

so 0.09911770099 grams is the answer if you round that you get about 0.1 grams

3 0

3 years ago

Read 2 more answers