Formula mass is used for which of the following substances?
Formula mass is used for ionic compounds. Because ionic compounds don't exist as individual molecules hence we take simplest ratio of elements present in that compound so we can't take it as molecular mass. Hence separate name formula mass is given. For example formula mass of NaCl is 23+35.5=58.5
Which of the following is an element?
Copper is a chemical element with symbol Cu and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity.
Substances whose two or more components completely mix with each other to make a uniform composition are called:
Homogeneous Mixture: Mixtures having a uniform composition throughout their body are called Homogeneous Mixtures.
Example: a mixture of salt and water, a mixture of sugar and water, air, lemonade, soda water, etc. Here, a mixture of salt in water is a classic example. This is because here, the boundary, between salt and water can never be differentiated. When a ray of light is passed through the mixture of salt and water, the path of light is not seen.
Which of the following is a compound?
Water is a compound
1) Its constituents hydrogen and oxygen is present in fixed ratio, i.e., 2:1 (H2O).
2) Its properties are different from its constituents elements ( hydrogen and oxygen).
3) Its constituents cannot be separated by simple physical means but requires chemical methods.
4) Water has a fixed boiling point, which is different from that of both hydrogen and oxygen.
Arsenic is a/an:
Arsenic is a chemical element with symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, but only the gray form, which has a metallic appearance, is important to industry.
A pure substance can only be:
A pure substance is a substance in which only one type of atom or molecules is present. For example, water, sulphur, sucrose(pure), helium etc.
Hence, a pure substance can only be an element or a compound.
Which of the following is a characteristic property of both mixtures and compounds?
Mixture and a compound both follow the law of conservation of mass so their weight equals to the sum of mass of their components.
The correct relationship between picometer and nanometer is
One sample of air is found to have 0.03% carbon dioxide and another sample 0.02%. This illustrates that:
Which one of the following is not a mixture?