Roland asked in 科學及數學化學 · 1 decade ago

科學難題(exam)...急需幫手!!

1)The formula for Sodium Chloride is Nacl. If the symbol of a chloride ion is cl1-, deduce the charge of a sodium ion. Explain your answer.

2)Hydrogen peroxide, H2O2, is a colorless liquid.

Hydrogen peroxide decomposes according to the equation below.

Hydrogen peroxide -> water + oxygen

(a) State the total number of atoms which are bonded in one molecule of hydrogen peroxide.

3)state the total number of electrons in a chlorine ion

4) Which of the following statements is correct?

A. Mass and weight are different names for the same thing.

B. The mass of an object is different if the object is taken to the moon.

C. The weight of a car is one of the forces acting on the car.

D. The weight of a chocolate bar is measured in kilograms.

Update:

isn't it Na, positive sign.. for the first question?

like this: Na+cl-

Atoms may gain or lose electrons, to become ions. Positive and negative ions are strongly attracted to each other, so therefore the sign for Na must me positive. isn't it?

1 Answer

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  • 1 decade ago
    Best Answer

    1)The formula for Sodium Chloride is Nacl. If the symbol of a chloride ion is cl1-, deduce the charge of a sodium ion. Explain your answer.

    charge is negative, as a minus sign on the symbol means the ion carry a negative charge, while a plus sign on the symbol means the ion carry a positive sign.

    2)Hydrogen peroxide, H2O2, is a colorless liquid.

    Hydrogen peroxide decomposes according to the equation below.

    Hydrogen peroxide -> water + oxygen

    (a) State the total number of atoms which are bonded in one molecule of hydrogen peroxide.

    hydrogen peroxide =H2O2= 4 atoms are bonded in one molecule

    3)state the total number of electrons in a chlorine ion

    Cl-1, as a chlorine atom carry 17 electrons and with one more electron is added, a chlorine ion carry 18 electrons.

    4) Which of the following statements is correct?

    A. Mass and weight are different names for the same thing.

    B. The mass of an object is different if the object is taken to the moon.

    C. The weight of a car is one of the forces acting on the car.

    D. The weight of a chocolate bar is measured in kilograms.

    A: False. mass means the quantity of atoms in an object, weight just means how much the object weigh

    B:False. Mass will not change in anywhere.

    C:Ture. the car is pulling by the force of gravity so the weight of a car is one of the forces acting on the car.

    D:False. a bar of chocolate should use grams to be measured

    2009-06-21 15:47:18 補充:

    Yes, you can't see any charge on the compound NaCl, that means NaCl is neutral in charge. to balance the negative charge of the chlorine ion( actually, sodium donate 1 electron to the chlorine atom, so chlorine become an ion), sodium has to be carrying positive charge(1+).

    2009-06-21 15:47:21 補充:

    we can call this a ionic bond as it is bonded by the attracting of an anion and a cation.

    Source(s): Form 6
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