purplewolf266

Mathematics fractions:

Darius, Ellen and Farhan each had some marbles. They traded marbles with one another. In the 1st round, Darius gave 1/5 of his marbles to Ellen.

In the 2nd round, Ellen gave 1/4 of his marbles to Farhan.

In the 3rd round, Farhan gave 1/2 of his marbles to Darius.

Darius had 45 marbles, Ellen had 30 marbles, and Farhan had 25 marbles left in the end.

How many marbles had each of them at first?

0.545 mole of krypton gas at temperature of 26 0C is found to occupie volume of 27.8 liter. Calculate the pressure of gas in mmHg.

Nitric acid (aq) + sodium hydroxide(aq)

Sulfuric acid (aq) + sodium hydroxide (aq)

Balance the following: 

(b)   

John has B bats and buys C bats more. He then gives away D bats. Which of the following algebraic statements corretly shows how many bats John has left?

1. Explain the difference between an exothermic and an endothermic reaction. Give the sign of ΔH for each type of reaction.

Please answer a and c 

Calculate the energy of a photon having a wavelength in the following ranges.