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4 years ago

In general, which properties are common to elements within a single group on the periodic table?

1 answer:

7 0

Almost all properties are common to elements within a single group on the periodic table. They react with water in the same way, they have the same number of valence electrons thereby having the same valency, the number of shells in the atom of the element increases by one as we move down the group.

In general, they have the same chemical properties as chemical properties depend on the number of electrons in the valence shell i.e. the outermost shell in the atom of an element.

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NaCl has a mc032-1.jpgHfus = 30.2 kJ/mol and a mc032-2.jpgHvap = 171 kJ/mol. What mass of NaCl releases 452 kJ of heat as it cha

Alex_Xolod [135]

Answer: option 3) 155 g

Explanation:

1) Releasing energy means that it changed from gas to liquid (or liquid to solid, but it is told that the NaCl changed into liquid).

That is because molecules in gas state are more energetic than in liquid state (molecules in gas state have more kinetic energy than molecules in liquid stated).

2) So, that means that the corresponding process is condenstation, and you have to use the latent heat of vaporization which is told to be 171 kJ/mol.

3) Calculations:

i) number of moles, n:
452 kJ = n × 171 kJ/mol ⇒ n = 452 kJ / 171 kJ/mol = 2.643 moles

ii) mass:
mass = n × molar mass = 2.643 moles × 58.443 g/mol = 154.46 g ≈ 155 g

3 0

4 years ago

Read 2 more answers

I’m so confused please help on how to balance all these equations!

Arisa [49]

Answer:

Explanation:

Synthesis Reaction:

The reaction in which two or more molecules or compound combine together to form a new compound.

1. K + Cl₂ --------> KCl

Balanced equation

2 K + Cl₂ -------->2 KCl

--------------------------------------

2. Ca + F₂ --------> CaF₂

Balanced equation

Ca + F₂ --------> CaF₂

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3. Ag + S --------> AgS

Balanced equation

2Ag + S --------> Ag₂S

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4. Na + I₂ --------> NaI

Balanced equation

2 Na + I₂ --------> 2 NaI

--------------------------------------

5. Mg + O₂ --------> MgO

Balanced equation

2 Mg + O₂ --------> 2 MgO

--------------------------------------

6. H₂ + Cl₂ --------> HCl

Balanced equation

H₂ + Cl₂ --------> 2 HCl

____________________________

Decomposition reaction:

when one compound breaks down into 2 or more molecule or components.

7. Cs₂O --------> Cs + O₂

Balanced equation

2 Cs₂O --------> 4 Cs + O₂

--------------------------------------

8. H₂O --------> H₂ + O₂

Balanced equation

2 H₂O --------> 2 H₂ + O₂

--------------------------------------

9. MgBr₂ --------> Mg + Br₂

Balanced equation

MgBr₂ --------> Mg + Br₂

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10. AlCl₃ --------> Al + Cl₂

Balanced equation

2 AlCl₃ --------> 2 Al + 3 Cl₂

--------------------------------------

11. KI --------> K + I₂

Balanced equation

2 KI --------> 2K + I₂

--------------------------------------

12. NaCl --------> Na + Cl₂

Balanced equation

2 NaCl --------> 2 Na + Cl₂

_______________________________

Combustion:

when a fuel burn in the presence of oxygen and produces carbon dioxide and water.

13. C₃H₈ + O₂ --------> CO₂ + H₂O

Balanced equation

C₃H₈ + 5 O₂ --------> 3 CO₂ + 4 H₂O

--------------------------------------

14. C₂H₄ + O₂ --------> CO₂ + H₂O

Balanced equation

C₂H₄ + 3 O₂ --------> 2 CO₂ + 2 H₂O

7 0

4 years ago

What is another name for base? in chemistry

dedylja [7]

Answer:

chemical species

Explanation:

8 0

3 years ago

Read 2 more answers

Assume that the density and heat of combustion of E85 can be obtained by using 85 % of the values for ethanol and 15 % of the va

Alika [10]

Answer:

87.4 J

Explanation:

The density of the gasoline is 0.70 g/mL, and the density of the ethanol is 0.79 g/mL. The heat combustions (the heat released in a combustion reaction) are 5,400 kJ/mol for gasoline, and 1,370 kJ/mol for ethanol.

For 3.5 L of E85, the volumes of gasoline and ethanol are:

Vgasoline = 0.15 * 3.5 = 0.525 L = 5.25x10⁻⁴ mL

Vethanol= 0.85 * 3.5 = 2.975 L = 2.975x10⁻³ mL

The mass of gasoline and ethanol presented in that sample of E85 is the volume multiplied by the density:

mgasoline = 5.25x10⁻⁴ * 0.70 = 3.675x10⁻⁴ g

methanol = 2.975x10⁻³ * 0.79 = 2.35025x10⁻³ g

The number of moles for each substance is it mass divided by its molar mass. The molar masses are 114 g/mol for gasoline, and 46 g/mol for ethanol:

ngasoline = 3.675x10⁻⁴/114 = 3.224x10⁻⁶ mol

nethanol = 2.35025x10⁻³ /46 = 5.109x10⁻⁵ mol

The energy released is the heat combustion multiplied by the number of moles, so:

Egasoline = 5,400 * 3.224x10⁻⁶ = 0.0174 kJ = 17.4 J

Eethanol = 1,370 * 5.109x10⁻⁵ = 0.07 kJ = 70 J

So, the energy released by the E85 is the sum of the energy released by ethanol and gasoline:

The energy released by E85 = 87.4 J

8 0

3 years ago

What is the molar of mass of copper (II) sulfate CuSOu?

Aleksandr-060686 [28]

191.546,,,,,,,,,,,,,,,,,,,

8 0

3 years ago