Would this button trigger alarm circuit work?
What Oli said, and:

Constructive comment: 

"Just conceptual" is understood BUT if too conceptual then actual required details may be  missed.

Opamp inv/non-inv inputs should be labelled. 

OA input to ground MUST instead have a voltage divider. 

AND gate input should not be assumed to float* to level of your choice when O/C. 

Put buzzer in parallel with LED+R.
 LED in series with buzzer reduces available buzzer voltage and sets max current to LED limit.   

Opamp output current drive will be small  usually.
 Buffer a good idea (1 transistor emitter follower often enough.
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Intention understood - BUT switch cct shorts supplies.

Many free cct dwg packages available. Or hand draw. 



"Floating" pins:

A "floating" connection (usually an input) is one which has nor formal drive and so whose value is dependent on leakage currents or on unspecified circuit characteristics. 

In this case, the "upper" input to the AND gate is high when the switch is closed but is undefined when the switch is open. 



You need a "pull down" resistor from AND input to ground to be sure this happens. Oli has shown this as R5. 

SOME logic families do "float" to predefined conditions (eg true bipolar TTL float high) but most CMOS families are undefined. Minor leakage paths can define what a floating CMOS input does and stray capacitance  may hold them in one or other state for a considerable period until leakage changes them, making operation unpredictable. 



You may "prefer" Paint, even though it is harder to do a good job with it than by using some of the free packages available that are made for drawing good quality circuit diagrams. That's a personal choice, BUT if you do use Paint,  the result has to meet a minimum level to be acceptable. You haven't managed that yet but will be able to do so with due effort. Paint can do this but it is harder to do than when using  a "proper" tool.