7.
某固态物质加热后成了液态,随后停止加热,并记录温度与时间的变化关系如下表\(.\)请你分析实验数据并回答:
时间\(/min\) | \(0\) | \(2\) | \(4\) | \(6\) | \(8\) | \(10\) | \(12\) | \(14\) | \(16\) | \(18\) | \(20\) | \(22\) | \(24\) |
温度\(/℃\) | \(98\) | \(91\) | \(85\) | \(82\) | \(79\) | \(79\) | \(79\) | \(79\) | \(75\) | \(71\) | \(67\) | \(64\) | \(61\) |
\((1)\)该物质________晶体\((\)选填“是”或“不是”\()\),其理由是________;
\((2)\)在第\(10min\)该物质的状态是________\(.(\)选填“固态”、“液态”、“固液共存态”\()\).
\((3)\)其中在\(8min~14min\)是________热过程\((\)选填“吸”或“放”\().\)内能\((\)选填“增大”、“减小”或“不变”\()\)