First year chemistry 碁 Please answer in detail, thank you 28 18 23 4

Sieborg said.

Sieborg (1912, 1999).

Seaborg, Glenn Theodore, American nuclear chemist. Born on April 19, 1912 in Ishperming, Michigan, USA. He graduated from the University of California, Los Angeles in 1934 and received his Ph.D. in chemistry from the University of California, Berkeley in 1937.

He was a professor of chemistry at the University of California, Berkeley, for a long time, and since 1961 has been chairman of the U.S. Atomic Energy Commission. He is currently a university-wide professor emeritus at the University of California, including nine campuses, and is also the associate director of the Lawrence-Berkeley Laboratory.

Set: nails, buttons, nuts are a gram, b gram, c gram quality.

So, according to the title, there are: 2a = 5b = 4c ......①

4b=3c+1……②

By, b=4 5c......③

Substituting , we get: 16 5c=3c+1

So, c = 5

Substituting , we can know that b=4 a=10

So, the nail mass is 10 grams, and the button mass is 4 grams.

For the first time, if you put 5 buttons in the right plate, then the mass of 5 buttons = the mass of 2 nails, if you put in 4 nuts, then 4 nuts = 2 nails, so 5 buttons = 4 nuts. Button = 4/5 nut.

The second time, put 4 buttons on the left plate, 3 nuts and 1 weight of 1 gram on the right plate, so.

2 nails + 4 buttons = 5 buttons or 4 nuts + 3 nuts and 1 weight of 1 gram, which can be replaced with 4 nuts + 4/5 nuts multiplied by 4 = 7 nuts + 1 gram.

Simplified to ——— 3/56 nut = 35/5 nut + one gram.

1/5 nut = one gram.

One nut = 5 grams The nut multiplied by 4/5 equals the button = 4 grams, so the nail is equal to 10 grams.

Do you have chemistry in the first year of junior high school now?

That's fast.

Biomass energy - mechanical energy - electrical energy.

There's a voice-activated switch in the electricity that causes air to vibrate when it's slapped, and the switch closes and it moves.

Receive voice-activated messages from the remote control.

Oxygen difluoride is not an oxide. The definition is good, but the valence state of oxygen should be negative, and the valence of oxygen in of2 should not belong.

Dioxygen difluoride is an inorganic compound with the chemical formula O2F2 and a yellow solid at room temperature. It is an unstable and strong oxidizing agent that decomposes to OF2 and O2 at -160°C

No, here oxygen is positive and fluorine is negative monovalent, understand?

It is an oxide and at the same time it is fluoride.

F2 reacts with NaOH to produce this.

It's fluoride. o is +2 valence and f is -1 valence.

is fluoride because F shows a negative valent in of2.

And its Chinese name is oxygen difluoride.

It is not the of2 that oxygen is +2 valence, not the usual 2 valence.

No, it's fluoride.

Oxygen in oxides has a negative valence, while oxygen in oxygen difluoride has a +2 valence.

Hydrochloric acid and zinc reaction.

Phenomenon: Zinc flakes gradually dissolve, and colorless gas is generated.

Hydrochloric acid and rust reaction.

Phenomenon: The rust gradually dissolves and the solution turns yellow.

Hydrochloric acid and copper oxide reaction.

Phenomenon: The copper oxide gradually dissolves and the solution turns blue-green.

Hydrochloric acid and copper hydroxide reaction.

Phenomenon: Copper hydroxide gradually dissolves and the solution turns blue-green.

Hydrochloric acid and BaCl2 reaction.

Phenomenon: No obvious phenomenon.

Zinc dissolves gradually. There are bubbles popping up.

The rust gradually dissolves. The liquid turns yellow.

The black copper oxide dissolves and the solution turns green.

The blue copper hydroxide dissolves and the solution turns green.

Zinc dissolves gradually. There are bubbles popping up.

The rust gradually dissolves. The liquid turns yellow.

Copper oxide gradually dissolves. The liquid turns green.

Copper hydroxide gradually dissolves. The liquid turns green.

There is no obvious phenomenon.

1. Spread out the parasol and hang a thermometer under the umbrella.

2. Hang another thermometer under a tree.

3. After a period of time (e.g. 15 minutes), observe the indication of the two thermometers at the same time.

Experimental phenomenon: The number of thermometers under large trees is lower than that of thermometers under parasols.

The leaves can absorb light energy and store it, so the temperature under the tree is lower than under the parasol, and the thermometer doesn't know if it can be compared.

Use two clothes with the same humidity and the same material to dry under a large tree and under a parasol respectively, and compare which one dries faster.

Because the sum of the two sides of the triangle is greater than the third side.

So a+b>c

Convert b-a-c to b-(a+c).

then b is a+b-c - b-a-c =a+b-c-a-c+b=2b-2cok!

This is a problem where the sum of the two sides is greater than the third side, so a+b-c>0 b-a-c<0 problem.

So it is simplified to a+b-c-(a+c-b)=a+b-c-a-c+b=2b-2c

｜a+b-c｜-｜b-a-c｜

a+b-c｜-｜a+c-b｜

Since the sum of the two sides of the triangle is greater than the third side, so.

Original = a+b-c-(a+c-b).

2b-2c

Any 2 sides of the triangle and greater than the 3rd side The original equation = a+b-c-a-c+b=2b-2c

The first is formed into a+b-c, because the sum of the two sides is greater than the third side, and the latter is formed into b-(a+c) =a+c-b, so the final answer is a+b-c+a+c-b=2a, so choose a

Because the sum of the two sides is greater than the third side, and the difference between the two sides is less than the third side, a+b-c>0, b-a-c<0

So the original formula = a+b-c-(-b+a+c).

a+b-c+b-a-c

2b-2c, so d should be chosen

Choose da+b c, b-a-c = b-(a+c), the absolute value of the decimal minus the large number = the large number decreases.

i.e. a+b-c-(a+c)+b=2b-2c

=1+2+3+(-4+5+6-7)+(8+9+10-11)+(12+13+14-15)+(16+17+18-19)+(20+21+22-23)+(24+25+26-27)-28 (the results in parentheses are all 0).

There are not many formulas, so you don't need to find a pattern, just calculate it by hand.

Uh, are you sure it's the first question?

Such a high IQ question is not a postgraduate examination question?

It took me a lot of brain cells and a lot of mathematical theorems to figure out that this is equal to -22