Generally, Asian part of Russia is considered all territory from Ural Mountains to the Far East (Sea of Okhotsk)
Russia was invaded by the Nazis from the sea and onto the eastern part of Russia but not Siberia.
Eastern Russia
No. Most of Russia is in Asia. The part that is in Europe is in eastern Europe.
Siberia
Russia (and the continent of Eurasia, large part of which Russia occupies) is divided by the Ural mountains into the European (or western) part and the Asian (or eastern) part. Moscow, the capital of Russia, is to the west of the Urals. Therefore, it is in the western part of the country. Note that while the eastern part of Russia is considerably larger in terrirtory, most of the population lives in the western part, and most of the large cities are found in the western part as well.
The eastern part of Russia
Obviously, it's The Pacific!
Part of Russia is situated in Eastern Europe, the rest is in Asia
Moldavia is not part of Russia, it is a geographic and historical region in Eastern Europe. Western Moldavia is presently part of Romania, the Eastern part is now the Republic of Moldova and the northern and south-eastern parts are now parts of Ukraine.
Eastern Front
Abrene
Moldova is an European country, between Romania and Ukraine. Moldova is not now a part of Russia. Moldova was integrally an historical province of Romania. Note that after the Ribbentrop-Molotov pact (1939) the central-eastern part of Moldova (Basarabia) become a province of Russia and the South eastern part become a part of Ukraine.