The question, as stated, cannot be answered sensibly. A cubic centimetre per hour is a measure of volume per hour, with dimensions [L3T-1]. A microgram is a measure of mass, with dimensions [M]. The two measure different things and elementary dimensional analysis teaches that you cannot convert between measures with different dimensions such as these without additional information. Althernatively, a microgram per hour is a measure of mass per hour with dimensions [MT-1] but the rest of the argument remains unchanged.
As a simple mental exercise consider a cc of air and of water. They will have very different masses.
1000 mg per gram
100mg = 100,000 micrograms (1000mcg per mg).
(542 mg) / (1,000 mg per gram) = 0.542 gram
0.25mg equates to 250mcg (1000mcg per mg).
15. Theer are 1000 mg per gram
620 (mg per liter) = 62 mg per deciliter.
1000mcg per mg
There are 109 mg per dL.
One million mg per kg
500mcg equals 0.5mg (1000mcg per mg).
10200mcg (1000mcg per mg).
One dram is 3,888 mg
about 148 mg per grapefruit.
1.5mg (1000mcg per mg).
0.1cg per milligram.
400mcg (1000mcg per mg).
0.75mg (1000mcg per mg).