| Keyword | CPC | PCC | Volume | Score |
|---|---|---|---|---|
| what country used chemical weapons in ww1 | 0.73 | 1 | 7353 | 5 |
| first use of chemical weapons in ww1 | 0.06 | 1 | 5328 | 54 |
| chemical weapons in wwi | 0.39 | 1 | 7513 | 92 |
| how effective were chemical weapons in ww1 | 0.46 | 1 | 6946 | 97 |
| what chemical warfare was used in ww1 | 1.59 | 0.4 | 598 | 82 |
| german chemical weapons ww1 | 1.73 | 0.2 | 2442 | 47 |
| chemical weapons in ww2 | 1.63 | 0.5 | 5103 | 3 |
| chemical weapons in world war 2 | 1.06 | 0.7 | 223 | 60 |
| chemicals used in ww1 | 0.83 | 0.2 | 6389 | 2 |
| first use of chemical warfare in ww1 | 1.95 | 0.8 | 2897 | 5 |
| were chemical weapons used in ww1 | 1.03 | 0.1 | 8720 | 50 |
| first use of chemical weapons | 1.77 | 1 | 2364 | 64 |
| chemical warfare weapons in ww1 | 0.95 | 0.1 | 3614 | 93 |
| chemical weapons in world war 1 | 0.69 | 1 | 2580 | 73 |
| chemical weapons in world war i | 0.02 | 0.9 | 8029 | 12 |
| what chemical weapons were used in ww1 | 0.53 | 0.7 | 3035 | 63 |
| where chemical weapons used in wwi | 0.12 | 0.3 | 3187 | 86 |
| was chemical weapons used in ww2 | 0.63 | 0.3 | 9849 | 47 |
| did germany use chemical weapons in ww1 | 1.08 | 0.2 | 2288 | 34 |
