"It is hot tea."
I'm pretty certain both can... are you sure the sentences were the same? Because there is a difference between "this tea is hot" and "this is hot tea".
This tea is hot: このおちゃはあついです
This is hot tea: これはあついおちゃです
It is hot tea: あついおちゃです
Both あつい and つめたい don't change when you put them in front of the noun because they are i-adjectives. For na/no adjectives you have to conjugate them, so the difference is clearer.
Not to steal your spotlight, but to make it easier to read
This tea is hot: この茶は暑いです
This is hot tea: これは暑い茶です
It is hot tea: 暑い茶です
暑い = あつい, hot.
The following things are also あつい, but not hot (in the correct sense)
熱い = Heated, passionate, zealous, intense, severe, hot (topic)
厚い = Thick, heavy, deep, cordial, kind, serious (of an illness)
篤い = Alternative kanji to previous.
茶 = ちゃ, Tea
おちゃ often refers to green tea, or gives reverence to the tea, such as tea served in a traditional ceremony. Also お茶 can be used for a tea break at work.
It helps to read the important particles and adjective suffixes (い) without muddling the meaning.
According to jisho.org, 熱い is used for hot things, which would include tea. I found this sentence on a Japanese site: 暑いけど熱いお茶飲むよ (あつい'けど'あつい'おちゃ'のむよ / It's hot (weather), but I'm drinking hot tea). Do a google search for both 熱いお茶 and 暑いお茶 and you'll see with the first one that you can find actual examples of the phrase coming up, while with the second one you will see a lot of results for hot days or hot summer, but not hot tea.
For the love of anything, don't use google translate for any attempts to learn a language. There are no -いい in any word, but it can be used in, say, manga to emphasize a drawn-out word, " 痛いい．．．っっっっ" or something similar is not that uncommon.
If you hear a double "i" sound, it is most likely an i following "shi", "ki" or similar phonetic.
And no, when placing an i-adjective in front of a noun, nothing gets removed, quite the contrary. Functionally speaking, apart from a couple of exceptions(like with any rules concerning languages), there are no adjectives in japanese. Most adjectives are formed by adding い behind them to turn them into descriptive, while other words use な or even in rare cases even の is used to attribute a quality to a noun.
Those mark the subject/topic, which is omitted here. To say something "is noun" you just have to use noun+です. For example, "is student" would be "がくせいです", but if you wanted to make it clear who you were talking about you could say, for example, "[かのじょは]がくせいです" for "[she] is student". Usually the かのじょは part would be obvious from context, which is why it's often left out unless it's unclear.
In this example, maybe someone saw a cup on the table and asked "あれはなんですか" (what is that?). The full reply would be ”[あれは]おちゃです” ([that] is tea), but that's a little redundant since it's already clear what you're talking about, so the あれは part can be dropped and the reply could be just "おちゃです" (is tea), or more specifically, "あついおちゃです" (is hot tea). The あつい part just modifies the noun, and doesn't change the rest of the sentence structure.
Note that this is different than saying something like, "the tea is hot". In that case "tea" would be the topic/subject and you can say ”[おちゃが]あついです” ([tea] is hot). Or, if the context is clear, just "あついです" (is hot).
It is still in development. Some kanji are not accepted primarily because it has not been taught, but you are correct in the importance of kanji. If you are 100% certain that the sentence is correct and you didn't pick the wrong kanji, then report the answer as correct.
熱い is for when a thing is hot, such as tea.
暑い is for weather.
Crikey, first get cold as first word, then the next has the object in front of hot. Then with this one hot is in front again, just like cold.
Everytime I think i understand the grammar it turns it all upside down again.
Translating to english is easier, because English grammar is consistant.
Seriously come on Duolingo! Kanji not being accepted is just ridiculous, especially since this has evidently been reported by multiple people for at least half a year!
This is the kind of sloppiness that makes me doubt Duolingo is serious about this business.
熱いお茶です あついお茶です 熱いおちゃです