The balanced equation for the neutralisation reaction is as follows
Ca(OH)₂ + H₂SO₄ ---> CaSO₄ + 2H₂O
stoichiometry of Ca(OH)₂ to H₂SO₄ is 1:1
equivalent number of acid reacts with base
number of H₂SO₄ mol reacting - 2 mol
according to molar ratio of 1:1
number of Ca(OH)₂ mol = number of H₂SO₄ moles
therefore number of Ca(OH)₂ moles required - 2 mol
Answer: (3) They have different masses and the same charges.
Explanation:
Atoms are mainly composed of three main types of particles (in fact there are more particles that are smaller and make up these main particles): electrons, protons and neutrons.
In the specific case of <u>electrons</u> and <u>protons</u>, <u>both have the same charge, but electrons have the opposite sign</u>. This means a proton has an electric charge of +1 and an electron has an electric charge of −1.
On the other hand, <u>protons have more mass than electrons.</u> In fact, thetex]mass of an electron is about approximately 
the mass of a proton, this means these negative charged particles contribute almost nothing to the total mass of an atom (unlike protons, which together with neutrons, make up virtually all of the mass of an atom).
However, each atom that is electrically neutral has the same quantity of electrons as protons.
Answer:
1. Dissolving powder in milk - Chemical
- It is chemical because the milk has changed on a molecular level
2. Toasting bread - Chemical
- It is chemical because adding heat to the bread cooks it, therefore
changing it on a molecular level
3. Melting cheese - Physical
- It is physical because the physical appearance was the only change
4. Slicing apples or bannanas - Physical
- It is physical because the physical appearance was the only change
5. Frying an egg - Chemical
- It is chemical because new particles were formed
6. Milk souring - Chemical
- It is chemical because it is forming a new product (lactic acid)
Explanation:
Physical Change occurs when the particles of a substance become rearranged, but do not change into different particles.
Chemical change occurs when a new substance is formed. This process is irreversable.
Answer : The correct answer is Option D.
Explanation:
Ores are defined as natural occurring substance from which metals and another mineral are extracted.
Bauxite is primary ore of an aluminium metal. it doesn't have definite or specific chemical composition. This is because it contains mixture of hydrous aluminum oxide
, aluminum hydroxides
, insoluble materials like hematite, quartz ,geothite ,magnetite etc.
From the given options the most appropriate statement which is correct about the bauxite is 'It does not have a definite chemical composition'.
Hence, the correct option Is (D).
