Predict the precipitate when the double replacement reaction occurs:
ca(no3)2(aq) + na2co3(aq) →

The precipitate formed is calcium carbonate.

Explanation:

double replacement reaction is the chemical reaction in which two reactant  exchanges their respective ions to give new substance as a product.

AB+CD→CB+AD

In a given reaction:

When calcium nitrate reacts with sodium carbonate in aqueous they give white colored precipitate of calcium sulfate and aqueous solution of sodium nitrate.

answer: at 24 february, 2014 the population gets twice of its initial population.

explanation:

since we have given that

the population for alpha city, t years after january 1, 2004 is given as

first we find out the initial population, i.e. t=0,

so, our quadratic equation becomes,

according to question, we have said that if the population has twice its initial population, then it becomes

so, time taken to reach this above mentioned population is given by

now, we know that time can't be negative so, we take t=9.149 years.

hence, at 24 february, 2014 the population gets twice of its initial population.