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3 years ago

Which best describes an element?

Chemistry

1 answer:

Aleonysh [2.5K]3 years ago

6 0

I think the answer is a pure substance

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For elements (Br, Ca, Fe, Na, S, Si, and Xe) which of the following term(s) apply?

ioda

Answer:

Detail is given below.

Explanation:

Bromine: Br (Halogen and non metal)

Bromine is present in group 17 and it is called halogen.

All halogens are very reactive.

Calcium; Ca ( alkaline earth metal)

Calcium is present in group 2. It is alkaline earth metal.

It has two valance electrons.

Iron; Fe (Transition metal)

Iron is transition metal and also called d-block element.

Sodium: Na (Metal, main group element)

Sodium is metal and present in group one.

It has one valance electron.

Sulfur: S (non metal)

Sulfur is non metal. It is present in group 16.

It has six valance electrons.

Silicon: Si (metalloid)

Silicon is metalloid. It is present in group 14.

It has four valance electrons.

Xenon: Xe (Noble gas, gas at a room temperature)

it is noble gas. Xenon is present in group 18.

It is gas at a room temperature.

3 0

3 years ago

Most hottest month of the year

devlian [24]

Depends on where you live but generally speaking it is either June or July

7 0

3 years ago

Read 2 more answers

The percent by mass of copper in CuBr2 is

Sunny_sXe [5.5K]

Hope this helps you.

4 0

3 years ago

Read 2 more answers

Butane (C4 H10(g), Hf = –125.6 kJ/mol) reacts with oxygen to produce carbon dioxide (CO2 , Hf = –393.5 kJ/mol ) and water (H2 O,

WITCHER [35]

Answer: Enthalpy of combustion (per mole) of $C_4H_{10} (g)$ is -2657.5 kJ

Explanation:

The chemical equation for the combustion of butane follows:

$2C_4H_{10}(g)+4O_2(g)\rightarrow 8CO_2(g)+10H_2O(g)$

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

$\Delta H^o_{rxn}=[(8\times \Delta H^o_f_{CO_2(g)})+(10\times \Delta H^o_f_{H_2O(g)})]-[(1\times \Delta H^o_f_{C_4H_{10}(g)})+(4\times \Delta H^o_f_{O_2(g)})]$

We are given:

$\Delta H^o_f_{(C_4H_{10}(g))}=-125.6kJ/mol\\\Delta H^o_f_{(H_2O(g))}=-241.82kJ/mol\\\Delta H^o_f_{(O_2(g))}=0kJ/mol\\\Delta H^o_f_{(CO_2(g))}=-393.5kJ/mol\\\Delta H^o_{rxn}=?$

Putting values in above equation, we get:

$\Delta H^o_{rxn}=[(8\times -393.5)+(10\times -241.82)]-[(2\times -125.6)+(4\times 0)]\\\\\Delta H^o_{rxn}=-5315kJ$

Enthalpy of combustion (per mole) of $C_4H_{10} (g)$ is -2657.5 kJ

6 0

3 years ago

What was the key design change for hfc-134a a/c systems versus CFC 12 a/c systems

BabaBlast [244]

Answer is: key design change for HFC-134a A/C systems versus CFC-12 A/C systems was quick couple service fitting and that design reduce venting and mixing of refrigerants during service.

Level of contamination is also reduced and the emission of refrigerants and greenhouse gases (sulfur dioxide, carbon dioxide) is also reduced.

6 0

3 years ago