serial monitor closed, HM-10 TX connected to arduino RX and HM-10 RX connected to arduino TX.
my app connected to HM-10 and still didn't receive anything from arduino on my iphone!
where is my mistake?!
Your code works correctly with with one small error, but this is unrelated to your issue.
val2 = analogRead(tempPin2);
//float C2 = ( val1/1024.0)*500;
float C2 = ( val2/1024.0)*500;
There is something I don't understand about your environment with the HM 10 and the iphone app.
When I run this sketch with an HC05 connected to the Arduino (BT_TX to D0 and BT_RX to D1) and an Android terminal application every is working properly. The BT module is indeed sending to the phone, I see the two temperature readings on the phone screen, and if I leave the serial monitor window open the data is showing there as well.
You say the phone found and paired with the module and the app connected.
Are you certain that the iphone app is set for 9600 Baud?
Do the line endings match between the phone app and the serial monitor
What iphone do you have?
You might want to consider a simple Bluetooth Serial Terminal app like this one to test if the problem is with LightBlue app.
https://itunes.apple.com/us/app/hm10-bluetooth-serial-lite/id1030454675?mt=8