A fifth-grade science class puts half of a white tablet in a test tube with 10 milliliters (mL) of water at 21°C (70°F). The tablet bubbles rapidly for three minutes until it is gone. Students record the final temperature at 20°C (68°F). Which choice best identifies evidence that a chemical reaction occurred?

i think it table broke in half

Explanation:

it would be change in water temperature

Explanation: because the change in the water is the temperature and its is

evaporation

a basic solution is an aqueous solution containing more oh-ions than h+ions. in other words, it is an aqueous solution with a ph greater than 7. basic solutions contain ions, conduct electricity, turn red litmus paper blue, and feel slippery to the touch.

explanation:

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms