An experiment at Sandia National Labs in New Mexico is performed at an atmospheric pressure of
788.7 millimeters of mercury (mm Hg). What is this pressure in atmospheres (atm)?

1.0  atm

Explanation:

Millimetre mercury:

It is the monometric unit of pressure. It is define as "The pressure exerted by the column pf mercury at the height of 1 millimetre.

It is represented as mmHg.

It can also be written as mm Hg.

Atmosphere (atm):

It is barometric pressure, define as "The force exerted by atmospheric column on per unit area".

It is written as "atm".

Conversion of  mmHg to atm:

788.7 mmHg × 1 atm/ 760 mmHg

1.0  atm