so in this case.. we add "en" to the adjective because "der Reis" is in the accusative and would change to "den Reis"? Anyone know if that is correct?
That is mostly correct. However, it doesn't always follow this pattern exactly.
Review this link for more information: http://en.wikipedia.org/wiki/German_declension
More often, you must look at what does or doesn't precede the noun, the gender of the noun, and what case it is in.
And if you absolutely must make a guess and have no idea, use -en; it is by far the most common.
For colors / adjectives which precede nouns, how do you determine what ending to add?
The ending depends on three factors:
1.) article before the noun (der-words, ein-words or unpreceded)
2.) gender/number of the noun (masculine, feminine, neuter or plural)
3.) the case of the noun (nominative, accusative, dative or genitive)
E.g. in your example ("Ich esse weißen Reis"):
For more information, including charts of the endings, see the chapters on adjectives here: http://coerll.utexas.edu/gg/gr/index.html?si=adj
this chart http://www.nthuleen.com/teach/images/adjendflowchart.gif that almost always works, would suggest using weiß instead of weißen, as there is no article. could you clarify as to why the rule doesn't apply in this case so that we might know how to identify it in the future?
I have my own (more visual) strategy for memorizing all this info. It's tough, but arranging it this way made it easier for me.
Your tables are really helpful, I took Screenshots and bookmarked the page. Thank you.
to whiten , is to make something more white than it was before . if you polish brown rice , you get 'whitened' rice . how do you say 'whitened' in german ?
There is the verb "weißen" (to whiten) and the past participle "geweißt" (whitened): It means to paint walls, etc. in white, though, so you wouldn't use it with rice.
Just a note for others who might make the same mistake I made. Das Reis and Der Reis. One is the rice, the other is something else, a twig I think. Here of course they want Der Reis