Which of the following is not a simple machine

Write the full electron configuration of Si, Si+4 and Si-4. How many valence electrons are in each of the 3 Si atoms?

mars1129 [50]

<h3>Valence electron : 4 and 8</h3><h3>Further explanation </h3>

In an atom there are levels of energy in the shell and sub shell

This energy level is expressed in the form of electron configurations.

Charging electrons in the sub shell uses the following sequence:

The electron configuration of the element silicon (Si): 1s² 2s² 2p⁶ 3s² 3p²

valence electrons Si = 4

The electron configuration of the element silicon (Si) +4⇒releases 4 electron: 1s² 2s² 2p⁶

valence electrons Si⁴⁺ = 8

The electron configuration of the element silicon (Si) -4⇒gain 4 electron: 1s² 2s² 2p⁶ 3s² 3p⁶

valence electrons Si⁴⁻ = 8

3 0

2 years ago

Need help with this please thanks

kolbaska11 [484]

Answer: 1. $2H_2+O_2\rightarrow 2H_2O$

2. $P_4+3O_2\rightarrow 2P_2O_3$

3. $N_2+3H_2\rightarrow 2NH_3$

4. $2K+Cl_2\rightarrow 2KCl$

Explanation:

According to the law of conservation of mass, mass can neither be created nor be destroyed. Thus the mass of products has to be equal to the mass of reactants. The number of atoms of each element has to be same on reactant and product side. Thus chemical equations are balanced.

The given equations are balanced as:

1. $2H_2+O_2\rightarrow 2H_2O$

2. $P_4+3O_2\rightarrow 2P_2O_3$

3. $N_2+3H_2\rightarrow 2NH_3$

4. $2K+Cl_2\rightarrow 2KCl$

5 0

2 years ago

4. How many grams of ammonium carbonate are needed to decompose in order to produce

Thepotemich [5.8K]

Answer:

14.23g of (NH4)2CO3

Explanation:

We'll begin by writing the balanced equation for the reaction.

(NH4)2CO3 –> (NH4)2O + CO2

Next,, we shall determine the mass of (NH4)2CO3 that decomposed and the mass of CO2 produced from the balanced equation. This is illustrated below:

Molar mass of (NH4)2CO3 = 2[14+(4x1)] + 12 + (16x3)

= 2[14 +4] + 12 + 48

= 2[18] + 60 = 96g/mol

Mass of (NH4)2CO3 from the balanced equation = 1 x 96 = 96g

Molar mass of CO2 = 12 + (2x16) = 44g/mol

Mass of CO2 from the balanced equation = 1 x 44 = 44g.

Summary:

From the balanced equation above,

96g of (NH4)2CO3 decomposed to produce 44g of CO2.

Finally, we can determine the mass of (NH4)2CO3 that decomposed to produce 6.52g of CO2 as follow:

From the balanced equation above,

96g of (NH4)2CO3 decomposed to produce 44g of CO2.

Therefore, Xg of (NH4)2CO3 will decompose to produce 6.52g of CO2 i.e

Xg of (NH4)2CO3 = (96 x 6.52)/44

Xg of (NH4)2CO3 = 14.23g

Therefore, 14.23g of (NH4)2CO3 is needed to produce 6.52g of CO2.

4 0

3 years ago

Describe solids,liquids, and gases interms of how they fill a container. Use your descriptions to identify the physical state (a

nadezda [96]

Explanation:

As it is known that in solids, molecules are held together because of strong intermolecular forces of attraction. As a result, they are held together and have definite shape and volume.

Whereas in liquids, molecules are not held so strongly as they are in solids. Hence, they move from their initial position and they do not have definite shape but they have definite volume.

Liquids obtain the shape of container in which they are kept.

In gases, molecules are held together by weak intermolecular forces. As a result, they move far apart from each other and occupy the space of a container or vessel in which they are placed.

The physical state (at room temperature) of the following are determined as follows:

(a) Helium in a toy balloon : Helium at room temperature exists as a gas. So, when helium is present in a toy balloon then it acquires the volume of toy balloon.

(b) Mercury in a thermometer : Mercury at room temperature exists as a liquid. When it is placed in a thermometer then volume of mercury does not get affected.

(c) Soup in a bowl : Since, soup is a liquid. Hence, its volume will not change according to the volume of container.

3 0

3 years ago

In the periodic table how many elements could be classified as metals in group IV?

lord [1]

4 elements are classified in group 4 like titanium, zirconium, hafnium and ruthorfordium

8 0

3 years ago