к серной кислоте прилили раствор , содержащий 10.4 хлорида бария. Определите массу осадка

помогите пожалуйста 

sina+tga/1+cosa

напишите уравнение реакций ионного обмена приводящих к образованию 

бромида серебра
иодида серебра  

В треугольнике АВС внешний угол при вершине А равен 123 градуса, а внешний угол при вершине В равен 63 градуса,Найдите угол С треугольника АВС. Ответ дайте в градусах.

1. They go to school together in the morning, and always        at the same time. a) get up b) got up c) gets up d) has gotten up 2. Tina is a good student, but she always                   about her grades. a) worry b) worrys c) worries d) worried 3. Have you visited any European countries? - Yes. I                  Spain and Italy two years ago. a) visited b) have visited c) had visited 4. I went to Belgium last month. I             there before. It's a beautiful country. a) have never been b) had never been c) never was 5.1 love this film. I           it four or five times already. a) see b) have seen c) had seen 6. OK, I         the car. We can go. a) repairs b) repaired c) have repaired 7. She         lunch by the time we arrived. a) had finished b) finished c) have finished 8 .          you ever         to Hollywood? a) Did ... go b) Have ... go c) Have .. gone 9. Would you mind            me a hand? a) to give b) give c) giving 10. If she that he was coming, she          would have prepared the guest room. a) knew b) has known c) had know