Grade 9 before Unit 3 Molecular. Atom there chemistry practice question 50

I don't know the topic, but the homework shouldn't be the same.

Mine is the standard experimental textbook of compulsory education curriculum published by the People's Education Publishing House, and it just so happens that the third unit is "water in nature" and talks about the composition of molecules and atoms! (The following is the question I typed out myself, not other resources, there may be typos!) ）

Practice questions: Lesson 1 "Multiple choice questions:

1.The following belong to the presence of aerobic molecules in the substance are ( ).

a.Water bManganese dioxide cPotassium permanganate dLiquid air.

2.The fact that molecules can be redivided is ( ).

a.Flowers inside the wall, incense outside the wall bHeating mercury oxide produces mercury and oxygen cOxygen turns into a light blue liquid at -183 Water mixed with 100ml of alcohol, and the resulting volume is less than 200ml

3.If you look at the words of the little girl in the cartoon shown in the picture from a molecular point of view, it is correct ( ).

Comic content: Dad is sitting on the sofa smoking, and the little girl walks next to him and says, "It smells so bad, I'm smoking passively again".

a.The molecular mass is small bThere is a septum c. between moleculesThe molecular size is small dThe molecules are in constant motion.

4.The reason why oxygen can change from a colorless gas to a light blue liquid under the condition of pressurized cooling is ( ).

a.The oxygen molecule has changed bThe size of the oxygen molecule changes cThe interval between the oxygen molecules becomes smaller, while the oxygen molecules themselves do not change dIt is caused by changes in the oxygen molecule itself, and the interval between oxygen molecules becomes smaller.

5.The small molecule water for astronauts has the advantages of less drinking, long storage time in the human body, and less emissions. Astronauts drinking 125ml of small molecule water at a time can maintain the normal water requirement of the human body for 6 hours. The following statement about small molecule water is true ( ).

a.The chemical properties of the small molecule are altered bThere is no interval between water molecules in small molecule group water cThe water molecules in the water cease their motion dSome of the physical properties of small molecule cluster water are different from ordinary water.

Fill-in-the-blank questions: 6Scientific research has proven that matter is made up of tiny particles -- and so on.

7.A substance made up of molecules, Nuo is a pure substance made up of molecules, and Nuo is a mixture made up of molecules.

8.When a substance undergoes a physical change, its molecule itself When a substance undergoes a chemical change, its molecule itself

9.Using the knowledge of the molecule to explain:

1) Water evaporates faster in the summer than in the winter

2) Sugar water can be passed through the filter paper, instructions

3) Put the sugar into a glass of water, the whole glass of water has a sweet taste, it means

4) The liquefied gas is compressed into the cylinder because:

10.(1) Example 2: Elemental substances composed of molecules (write the name of the trait):

2) Someone said, "Count the number of molecules in each spoonful of water in the same way you count the water in the Atlantic Ocean with a spoon." This sentence illustrates that the characteristics that the molecule possesses are:

1. A student scratched his hand and applied disinfectant to the wound (the main ingredient is hydrogen peroxide H2O2), and found that there were bubbles on the wound, and asked what was generated was ---what is the gas) Water cannot be used as a disinfectant, but hydrogen peroxide can and oxygen cannot be disinfected, so it is concluded that oxygen --- disinfect.

Answer oxygen atom.

2 In chemical reactions,-- can be divided into atoms, and atoms can no longer be divided into molecules.

This is a fresh topic, it is hand-made, and I am willing to adopt it.

This problem can be used with extreme assumptions, assuming that the mixture is all magnesium oxide, and the gram of magnesium oxide is converted from grams of oxygen, which is larger than 4 grams, so when assuming that the mixture is all oxides of options, the grams obtained by calculating option A, option B, option C 6 grams, option D 9 grams, and only item B AL2O3

It's smaller than 4 grams, so I chose B, but the B option seems to be wrong.

(1) The mixture is composed of different kinds of molecules, and the pure substance is composed of the same kind of molecules.

2) The molecules are in constant motion.

3) The higher the temperature, the faster the movement rate of molecules, and the ventilation is more conducive to the diffusion of molecules.

4) If the molecules are constantly moving and are not sealed and preserved, the perfume and gasoline molecules will diffuse into the air, causing loss and waste.

5) The molecules do not change after the water evaporates, so the chemical properties do not change either.

6) There is a gap between the molecules, and the interval between the pressurized molecules decreases.

"A molecule is the smallest particle that retains the chemical properties of a substance" should be considered correct if you make a judgment question in middle school. But obviously not all matter is made up of molecules, so this sentence is not comprehensive. This sentence is spoken when talking about molecules, and of course does not take into account particles that are smaller than molecules.

All truths can only be established under certain conditions.

In chemical change, the molecule is divided into smaller particles - atoms", and then the atoms are recombined into new molecules, so that the old molecules become new molecules, the reactants become the products, the matter changes, and its chemical properties change, which reflects that "the molecule is the smallest particle that maintains the chemical properties of the substance".

This is the definition in junior high school textbooks, and in high school, it is said that "a substance made up of molecules, and molecules are the smallest particles that maintain the chemical properties of a substance", and in addition, molecules and atoms are particles that make up matter.

Something that is made entirely of atoms, and you think of them as a structure between atoms that is its molecules ... Remember it so that you don't mess up.

For example, water, H2O

You take a drop of water, divide, divide ...

The smallest thing is a water molecule ...

So a molecule is the smallest particle that retains the chemical properties of a substance.

You're cutting the water molecules, the H atom and the O atom ...

Substances are divided into mixtures and pure substances, pure substances are divided into elemental substances or compounds, elemental substances are substances composed of the same kind of elements, composed of molecules or atoms, for example, gases (except noble gases), are composed of molecules, mainly diatomic molecules, ozone is a triatomic molecule, and noble gases are composed of atoms. Solids (except iodine) are made up of atoms, and iodine is made up of diatomic molecules. Liquids have only bromine and are made up of atoms.

A compound is made up of two or more elements, either as a molecule or as an ion. Acid-base salt compounds are composed of ions, and organic matter and oxide are composed of molecules.

As mentioned earlier, molecules are made up of atoms (or ions). Atoms (ions) are made up of nuclei and extranuclear electrons, which in turn are made up of protons and neutrons, which in turn are made up of smaller quarks. As for whether quarks have smaller particles to make up for it, this remains to be studied.

Number of electrons outside the nucleus = number of protons = ordinal number in the periodic table.

Matter is made up of molecules or atoms or ions, molecules are made up of atoms or ions, and atoms are made up of smaller particles.

I can responsibly say that it was wrong, and that the writer of the textbook was wrong, and of course it could be that people think differently about the theory. At least in high school it was wrong. "Matter is composed of elements, and composition is made of particles" is true, I remember when I was in junior high school, there was a strict distinction between composition and composition, and the composition had to be composed of elements (for example, water is composed of hydrogen and oxygen, which cannot be said to be composed) to be able to be composed of particles (1 water molecule is composed of 2 H atoms and 1 O atom).

1.(1)b(2)b(3)b

The oxygen atom is composed of 8 protons, 8 neutrons, and 8 electrons. 8 protons and 8 neutrons make up the nucleus. Since the nucleus has 8 positive charges and the electrons outside the nucleus have 8 negative charges, the whole atom is not electrical.

4.Sodium is the most abundant, and aluminum is the least. Because sodium has the smallest relative atomic mass and aluminum has the most.

5.The atomic structure I imagined was like a flower bed or lawn in a park. However, I don't know how many times this magnifies the structure of the extremely small atoms!

In atoms, atoms have two good friends, one is the nucleus and the other is the electron. However, these two have caused a certain amount of inconvenience and trouble to the atom. Because the nucleus of an atom is positively charged, while the electrons are negatively charged.

This stumped the atom, and for the sake of fairness, the atom became one"Impartials", electroelectrically neutral. The problem of the atom is solved, and the nucleus has new troubles, and it turns out that there are also two good friends in the nucleus, one is a proton and the other is a neutron. Protons have a positive charge, but neutrons are not, what to do However, whoever is active will have a great influence, and whoever is"Juggernaut", so the nucleus of the atom has a positive charge according to the habit of the proton.

Who knew that protons and electrons soon became a pair of good friends again, inseparable, and you can have as many as I have. So they become one"Big family".

That's what I imagined the atomic structure to be, and it looked ordinary on the outside. If you use your own eyes to observe carefully and experience carefully, you will have more and greater new discoveries. They are waiting for us to explore them through our efforts and uncover one mystery after another"Baibao.

Write it yourself, and ask if you don't understand.

One. Two. The oxygen atom is made up of 8 protons, 8 neutrons, 8 electrons outside the nucleus.

Because an atom is made up of a nucleus and electrons outside the nucleus, the nucleus is made up of protons and seeds. And because the protons are positively charged, and the neutrons are not charged, then the nucleus is positively charged, and because the electrons are negatively charged, then the polarity of the atoms is opposite, and the positives and negatives are counteracted, so they are not charged.

Three n [Four. Aluminum is the largest because of its large relative atomic mass.

Sodium is the smallest because it has the smallest relative atomic mass.

2.8 protons 8 neutrons 8 extranuclear electrons The positive charge is opposite to the negative charge of the extranuclear electrons, so it is not electrically visible.