  We investigated some properties of coronal mass ejections (CMEs), such as
speed, acceleration, polar angle, angular width, and mass, using data acquired
by the Large Angle Spectrometric Coronagraph (LASCO) onboard the Solar and
Heliospheric Observatory (SOHO) from 31 July 1997 to 31 March 2014, i.e. during
the Solar Cycles 23 and 24. We used two CME catalogs: one provided by the
Coordinated Data Analysis Workshops (CDAW) Data Center and one obtained by the
Computer Aided CME Tracking software (CACTus) detection algorithm. For each
dataset, we found that the number of CMEs observed during the peak of Cycle 24
was higher than or comparable to the number during Cycle 23, although the
photospheric activity during Cycle 24 was weaker than during Cycle 23. Using
the CMEs detected by CACTus, we noted that the number of events [N] is of the
same order of magnitude during the peaks of the two cycles, but the peak of the
CME distribution during Cycle 24 is more extended in time (N >1500 during 2012
and 2013). We ascribe the discrepancy between the CDAW and CACTus results to
the observer bias for CME definition in the CDAW catalog. We also used a
dataset containing 19,811 flares of C-, M-, and X-class observed by the
Geostationary Operational Environmental Satellite (GOES) during the same
period. Using both datasets, we studied the relationship between the mass
ejected by the CMEs and the flux emitted during the corresponding flares: we
found 11,441 flares that were temporally correlated with CMEs for CDAW and 9120
for CACTus. Moreover, we found a log-linear relationship between the flux of
the flares integrated from the start to end in the 0.1 - 0.8 nm range and the
CME mass.We also found some differences in the mean CMEs velocity and
acceleration between the events associated with flares and those that were not.
