What is the ph value of water and salt?

Great amounts of electromagnetic energy from our sun and other bodies in space travel through space. which is a logical conclusion about these electromagnetic waves? their energy must be very their frequency must be very low these waves can travel without a medium they only travel through a vacuum of space

The activation energy for the reaction no2(g)+co2(g)⟶no(g)+co(g) is ea = 300 kj/mol and the change in enthalpy for the reaction is δh = -100 kj/mol . what is the activation energy for the reverse reaction?

A250 g sample of water with an initial temperatureof 98.8 closes 6500 joules of heat. what is the finaltemperature of the water?