What is the main function of the immune system?

To provide energy for the body

To circulate blood and nutrients

To defend against pathogens

All of the above

A liquid extracted from petroleum contains 92.3% carbon, the rest being hydrogen. Its molar mass is around 80 g/mol. Determine the empirical formula and molecular formula of the liquid.

Two major organic products are formed in the reaction of p-chlorotoluene with sodium amide. draw the structure of both products.

ethyl alcohol has a latent heat of vaporization of 860 J/g. water has a latent heat of vaporization of 2260 J/g. Container A contains 1.0 kg of ethyl alcohol. Container B contains 1.0 kg of water. Both liquids are brought to a boil.

Un-reactive elements include the last group of the periodic table.

State the oxidation number assigned to each bold element in the formula: NH4+1 a 3 b - 3 c - 1 d 6

How long does it usually take fir a rock to undergo a stage within the rock cycle

Calculate the ph of a solution formed by mixing 150.0 ml of 0.10 m hc7h5o2 with 100.0 ml of 0.30 m nac7h5o2. The ka for hc7h5o2 is 6.5 * 10-5.

Lead (ii) carbonate decomposes to give lead (ii) oxide and carbon dioxide: pbco3 (s) ? pbo (s) + co2 (g) how many grams of lead (ii) oxide will be produced by the decomposition of 2.50 g of lead (ii) carbonate?

Galena, a mineral of lead, is a compound of the metal with sulfur. Analysis shows that a 234-9 sample of galena contains 203 g of lead.

What is the relative charge carried by an electron