In both types of reactions, new substances are formed and there are changes in energy. However, endothermic reactions absorb energy, whereas exothermic reactions release energy. Reteach Change the boldface sentences into questions, and call on students to answer them.
The average monthly cell phone bill has soared in recent years to well over $100. A study earlier this year found that Verizon (VZ) was the most expensive carrier, with an average customer bill of $148 a month. Sprint (S) and AT&T (T) weren't that far behind, and T-Mobile (TMUS) was the least expensive of the Big Four carriers at $120.
Costs can range from $0.1 to $2 a minute. Verizon charges US customers $1.99 to connect and $0.20 per minute for voice calls when in Hong Kong, which is about average for US and Canadian networks. Remember you'll also pay to receive incoming calls.