Please help me! thank you so so much!!

What’s the scientific notation for the number 6,840,000,000

7. what temperature is need to just dissolve 50 g of nh4cl in 75 g of water? '

Which of the following two events occur to create a sea breeze? select all that apply. warm air rises on the ocean and moves toward the land to cool warm air rises on land and moves toward the ocean to cool cool air moves from the ocean to be warmed by the land cool air moves from the land to be warmed by the ocean