In the reaction of SiO 2 + 2C = = Si + 2CO, the oxidant is the reducing agent and the oxidant is the oxidizing agent In the reaction of SiO 2 + 2C = = Si + 2CO, the oxidant is the reducing agent, and the ratio of oxidant to reducing agent is 0

Oxidant SiO2
Reducing agent C
The molar ratio of oxidant to reductant is 1:2
Redox reaction use formula better memory, up oxygen loss, down also
The element whose valence rises loses electrons and oxidizes; the corresponding substance is reducing agent
The reduced and reduced elements get electrons and undergo a reduction reaction; the corresponding substance is an oxidant

SiO2 + 2C = Si + 2CO, SiO2 + 3C = SiC + 2CO?

You can't react. Although you can really conclude that Si and C can react by adding the two equations, you have to be clear that some reactions can't be spontaneous. You can compare the reaction of ethanol to acetaldehyde. The essence of this reaction is that Cu reacts with O2 to form Cuo, and then reacts with ethanol to form acetaldehyde. If there is no Cu, then ethanol can't react with O2

For example, Si + o2-sio2,

Silicon reacts with oxygen to form silicon dioxide
It should be like this

1. When bidding for a project, the project leading group receives bids from Party A and Party B. one day, Party A demands 15000 yuan, and Party B demands 11000 yuan
Plan 1: Party A completes the project alone, just in time
Plan 2, team B alone to do more than 5 days to complete the specified date
Plan 3: Party A and Party B cooperate for 4 days, and the rest will be done by Party B, which will be completed within the specified time
The calculation shows that which construction scheme can save the project cost most without delaying the project?
Let's do it with a quadratic equation of two variables,

The efficiency of a is 1 / X and that of B is 1 / (x + 5)
Then scheme 1: y = 1.5x;
2:y=1.1*(x+5)=1.1x+5.5
3:y=4*(1.5+1.1)+1.1*[1-4*(1/x+1/(x+5))]

The calculation problem of grade one in junior high school advances rapidly`````
|141 | + 141 | - 42|
|141 141| | 141 42 |
|---- - ---|+ | --- - ---|
|111 99 | | 111 99 |

|141 | + 42 | = 111 / 42 / 141 + 111 / 42 / 42 = 111 / 43 / 141
141 141| | 141 42 |
|---- - ---|+ | --- - ---|
|111 99 | 111 99 | I don't understand this

There are two fathers and two sons. Ten years ago, the father's age is 16 times that of his son. Eight years later, the father's age is 2.5 times that of his son. How old are the fathers and the sons now?

Suppose 10 years ago, the son's age was x and the father's was 16x. 8 years later, the son's age was x + 18 and the father's was 16x + 18
5 (x + 18) = 16x + 18
2.5x+45=16x+18
13.5x=27
x=2
So now the son's age is x + 10 = 12, and the father's is 16x + 10 = 42

Junior one's a mathematical problem, equation solution, the best solution process
Some of the same rooms need painting. Three first-class technicians go to paint eight rooms a day. As a result, 50 square meters of walls are not painted. In the same time, five second-class technicians paint another 40 square meters of walls in addition to 10 rooms. Each first-class technician paints 10 square meters of walls a day more than the second-class technician, so as to find out the wall area of each room that needs painting
The best equation is simple and easy to understand, thank you!

Suppose that a first-class mechanic can brush x square meters of wall in one day, a second-class mechanic can brush y square meters of wall in one day, and the painting area of each room is Z square meters
3X=8Z-50
5Y=10Z+40
X-Y=10
The nodal equations give x = 122, y = 112 and z = 52
That is, the painting area of each room is 52 square meters

To process several machine parts, Party A will do it for two days first, and Party B will join in the cooperation, and finish it in two days; if Party B will do it for two days first, and Party A will cooperate, then it will be finished in three days. It is known that Party A processes three times as many parts as Party B every day. How many parts can party A and Party B make each day?

Let a make x parts every day, B make y parts, and the total number of processed parts is Z
{2x+2(x+y)=z
{2y+3(x+y)=z
{x=3y
Then x = 3Z / 14
y=z/14

When they first meet, a is 104 meters away from B, and then they continue to walk forward. When they reach their destination, they both return immediately. When they meet again, B is 40 meters away from B. how many meters is the distance between a and B?
A. 124m b.144m c.168m d.176m

This is a problem of meeting for the second time: / - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

The average height of five people is 2 cm shorter than the average height of three of them, and the average height of the other two people is 166 cm. What is the average height of these five people

The average height of the five was 2 cm shorter than that of three of them, and the average height of the other two was 166 cm
So the average height of these three people is 166 + 2 = 168 cm
(168 * 3 + 166 * 2) / 5 = 167.2 cm

In the reaction of SiO 2 + 2C = = Si + 2CO, the oxidant is the reducing agent and the oxidant is the oxidizing agent In the reaction of SiO 2 + 2C = = Si + 2CO, the oxidant is the reducing agent, and the ratio of oxidant to reducing agent is 0