Chemistry problems, help, it s actually quite simple

It can be said that when a chemical change occurs, it will inevitably cause physical changes such as light, heat, color, and state, and it can be said that when a chemical change occurs, a physical change must occur.

125 is a physical property and 346 is a chemical property.

If a chemical change occurs, it is said to be a chemical property (that is, to see if there is a new substance formed when the property is reflected, if there is, it is a chemical change, and if there is none, it is a physical change).

1. When the candle burns, the paraffin wax changes from solid to liquid and from liquid to gaseous, which is a physical change.

Paraffin wax burns to produce carbon dioxide, water, which is a chemical change.

1) It is a physical property. Chemical properties are properties that are reflected in chemical changes, and this property can be directly observed and is a physical change.

2) Physical properties. This property is manifested through physical change.

3) Chemical changes. It is manifested through chemical changes (the formation of new substances).

4) Chemical changes. Ditto.

5) Physical changes. Same as 1).

6) Chemical changes. Same as 4).

1 Why is it said that there are both physical and chemical changes when a candle is lit?

When the candle burns, it melts is a physical change, and the combustion itself is a chemical change!

Physical properties: 1) Air is a gas with no color and no smell.

2) Water can turn into water vapor when boiling.

5) The density of copper is grams per cubic centimeter, and the melting point is 1083 degrees Celsius.

Causes: No new substances are produced;

Chemical properties: 3) Food is digested in the human body and can finally be turned into water, carbon dioxide, etc. (new substances).

4) Brewing can be made from grain (new substance).

6) Carbon dioxide can make the clarified lime water turbid (new substance).

new substances are produced;

Because paraffin wax becomes CO2 and H2O, there is a chemical change; The candle has become shorter, which is a physical change.

Also, remember, where there is a chemical change, there must be a physical change.

Physical properties: 1, 2, 5

Chemical Properties: 3, 4, 6

Because 1, 2, 5 does not need to be manifested by chemical change.

1.There is combustion indicating chemistry. The change of a candle into candle oil (liquid) indicates a physical change.

2.Physical Properties Physical Properties Chemical Properties Chemical Properties Physical Changes Chemical Changes.

Reason: Chemical changes need to be manifested by chemical changes.

Physical properties are expressed without chemical changes.

It's just always to say) detailed reasons based on this reasoning.

You have to use your own brains so that your head doesn't rust.

1.The candle melts to produce carbon dioxide under lit conditions 2 1Physical properties that are independent of the reaction.

2.Physics Unify the transformation between different forms of matter 3Chemical properties related to chemical reactions 4Same as iii 5Same 6Same as three or four.

(1) There is a surplus of ore in 3 4 reactions.

2) The value of m in the table above is.

3) Try to calculate the mass fraction of calcium carbonate in the limestone of this mine.

caco3+2hcl=cacl2+h2o+co2100 44

x100/x=44/

x=8g8g/10g*100%=80%

1..In experiments 1 and 2, the amount of carbon dioxide increased in the same proportion as the sample increased, and when the proportion decreased to 3, the proportion decreased indicating that there was still ore in the sample that did not react with hydrochloric acid. So it's 3,4 experiments.

Because there is so much hydrochloric acid. The amount of carbon dioxide is related to hydrochloric acid.

This is because hydrogen combustion only produces water, not carbon.

The poem is about the production of calcium carbonate with high purity from natural calcium carbonate, which has nothing to do with hydrochloric acid reaction.