Can I AV a physic guru to challenge myself with questions​

The chart shows the bid provided by four contractors to complete a job. which contractor is the most cost-effective?

How many moles of oxygen gas are produced from the decomposition of six moles of potassium

Consider the following reaction at equilibrium: c(s)+h2o(g)⇌co(g)+h2(g) predict whether the reaction will shift left, shift right, or remain unchanged upon each of the following disturbances. a) c is added to the reaction mixture. b) h2ois condensed and removed from the reaction mixture c) co is added to the reaction mixture d) h2 is removed from the reaction mixture.