A few chemistry questions with good extra points!

1b because zn represents zinc element, zinc atom, and elemental zinc (substance) 2d because the chemical term is like this, so2 co2 mno2 originally represents a molecule, it is impossible to have another oxygen molecule in it, it is correct to say that it contains oxygen, or 2 oxygen atoms.

3 Ca(OH)2 calcium hydroxide, which is the solute of lime water, which is used to paint walls.

100g contains at least calcium, then 250g of milk contains calcium.

90% of human calcium is obtained from milk, then it is the answer.

It cannot represent matter, C cannot represent atoms, and D cannot represent matter.

2.All three are chemical compounds, which are also pure substances, and if there is an oxygen molecule, it is a mixture. It's like making bread, you use an egg, but you can't say that there is an egg in the bread, the oxygen atom is just a part of the compound, like an egg.

4.A carton of milk has calcium.

People get their calcium from milk.

To box milk.

1.If I'm not mistaken, the d in the option should be carbon monoxide instead of cobalt. As the title suggests, the first is an element, excluding c and d; To represent an atom, both a and b can be; Represents a substance, A can't, oxygen atoms can't exist stably, and B can't, represents the metal zinc.

The mistake is that he says that these molecules contain molecules, and the book clearly states that molecules are made of atoms. There is no such thing as one molecule within another.

3.It is quicklime, the chemical formula cao calcium oxide.

4.(Box.)

Take the whole number of 2 boxes.

1 a does not represent a substance; c represents a molecule, not an atom; d also satisfies the above conditions, but I suspect it is a clerical error on the part of co.

2 d should be an oxygen atom.

3 Calcium hydroxide (hydrated lime).

4 i.e. two boxes.

Brother, you're so good, this is your homework.

Solid, colorless and transparent, filtered.

There is a red substance on the surface of zinc metal, zinc is greater than copper, CuSO4+ZN=ZNSO4

CU arrows. Bubbles are created on the limestone, extinguished. caco3

2HCLcaCl2+CO2+H2O arrows.

Correct. Fade away, brown yellow, acid solution, Fe2O3

6hcl=2

fecl3+3h2o

residue, evaporation crystallization.

Dissolution filtration. Red matter is generated.

The solution changes from blue to colorless.

Zinc is greater than copper. Zn+CuSO4=ZnSO4+Cu produces colorless gas.

Extinguish. CaCO3+2HCl==CaCl2+H2O+CO2 (arrow) positive. Disappear. Yellow.

Dilute hydrochloric acid. fe2o3+6hcl=2fecl3+3h2o

1.The law of conservation of oxygen a-b.

2. a+b-c

3. a+c-b

4.c, h, o are all available.

5. h2o

Assuming that both metals are all grams of a, the amount of hydrogen produced is respectively due to the sufficient amount of sulfuric acid.

Mg:24 2=a x gives x=a 12;In the same way, aluminum: 54 6 = a y to get y = a 9, compare x and y, y is greater than x, so aluminum produces more hydrogen.

mg+h2so4=mgso4+h2

24 2m m1=12m

2al+3h2so4=al2(so4)3+3h22*27 6

m m2=9m

So it is magnesium that emits more H2.

Write the chemical reaction equation well.

mg+h2so4=mgso4+h2

2Al+3H2SO4=Al2(SO4)3+3H2 It can be seen that one magnesium atom produces one hydrogen molecule, and two aluminum atoms produce three hydrogen molecules.

If both metals are one gram, there are 1 24 magnesium atoms and 1 27 aluminum atoms.

1 24 mg to generate 1 24 H2

1 27 AL generates 1 27 3 2 1 18 h2 so the mass ratio is 18 to 24, which is 3 to 4. So the mass of aluminum reaction to produce hydrogen gas is large.

The effect of putting manganese dioxide in is [ catalyst , reducing the energy required for the reaction and accelerating the reaction ] [2If the solution is not spoiled, the sight that should be observed is [bubbles are generated], if the above scene cannot be observed, it means that the hydrogen peroxide has deteriorated into [H2O].

If you drop this unexpired hydrogen peroxide on the wound, a large number of bubbles will quickly appear, and you think that the gas may be [oxygen].

Put a small amount of lipstick in a beaker with cold water, and after a while, the water in the beaker will gradually turn red, and in a beaker with hot water, it will gradually turn red, because the hot water dissolves faster

Among the following common substances, oxides are (c).

There are two or more substances that are a mixture! The solution is all a mixture!

1。Acts as a catalyst for the decomposition of hydrogen peroxide into oxygen and water.

2。There are bubbles that produce water.

3。Oxygen Put a small amount of lipstick in a beaker with cold water, and after a while, the water in the beaker will gradually turn red, and in a beaker with hot water, it will gradually turn red, because the hot water dissolves faster.

is an oxide an oxide is a compound and can only be composed of two elements The mixture is two substances.

A compound can only denote a substance mixture and a compound have something in common: they both contain a variety of elements.

Differences: The mixture contains two or more molecules or elemental atoms, such as H2O and NaCl are mixtures, and Fe and Al are also mixtures.

Compounds contain only one molecule, such as all H2O, or all HCl gas, and so on.

Based on your addition, I don't know how to say it, can you be specific about the topic before I can talk about it.

1 Catalysis.

2 There are bubbles coming out of H2O

3 o2 temperature polymer movement is violent.

4 a d

A:Co,CH4 combustion will produce H2O, CO2B:Co combustion will produce CO2 H2 combustion will produce H2OC:CH4 combustion will produce H2O,CO2

D:N2 does not burn at normal temperatures. At high temperatures, N2O can be generated, which increases the weight of NaOH.

Elimination solves this problem.

Anhydrous copper sulphate turning blue indicates that the product contains aqueous vapor and hydrogen in the gas.

The increase in the mass of sodium hydroxide solution indicates that the product contains CO2 and the gas contains element C.

As long as the gas does not contain elements H and C, the answer is the answer.

Option d only has the element h, the correct solution.

D, it's hard to explain to you. Fill it in first.

D must have carbon dioxide, and D can only produce water, water is all absorbed by a sufficient amount of anhydrous copper sulfate, nitrogen cannot be burned in oxygen, so D is chosen.

It cannot be d, because the anhydrous copper sulphate turns blue indicates that there is hydrogen in the generated water, and the increase in the mass of sodium hydroxide indicates the formation of carbon dioxide, which indicates the presence of carbon, while there is no carbon in d.