Is there a rule to when to use accents in Spanish?

Answer 1

Also,

¿Qué es esto? Should be written with an accent mark on top of the e (called tilde)

Accent marks have tilde when they are written.

the house: la casa. Has an accent on the first a but doesn't have a tilde, There is no accent mark written on top of the first a.

La casa que tiene ventanas al este. (The house that has windows facing east) Here que doesn't have a tilde (accent mark) because it is not part of a question.

Answer 2

Si'; there are a few rules. One, accents are used when the normal rules of spelling and pronunciation are broken. For example, for words that end in a vowel, n or s, the spoken stress falls on the second to last syllable. Examples are buRRIto, quesaDILLa, TAco and alFOMbra. For words that end in a consonant other than n or s, the spoken stress falls on the last syllable. Examples of this rule are as follows: animAL, papEL, and paRED. Examples of words in which these rules are broken and thus a written accent is required are: sábado, bolígrafo, and teléfono.

Another rule is that accents can change the meaning of a word. For example, 'si' means if and 'sí' means yes. 'sé' means 'I know' but 'se' is a pronoun, which can mean several things (to him, to her, etc.)