Can someone help me with this please

Three cards with holes are arranged in a straight line. a light is shined through the first card’s hole and travels through all three cards. what does this tell you about light rays? a) that light is reflected b) that light is refractive c) that light travels in a straight line d) that light does not travel in a straight line

Which statement about hf is true? it is zero for any compound in its standard state. it is positive when the bonds of the product store more energy than those of the reactants. it is negative when a compound forms from elements in their standard states. it is zero for any element that is in the liquid state.

Calculate the molarity of each aqueous solution: a. 78.0 ml of 0.240 m naoh diluted to 0.250 l with water b. 38.5 ml of 1.2 m hno3 diluted to 0.130 l with water