234+34.1 add and round to 2 significant figures

Since 1983, pennies have been made with zinc and plated with copper. Prior to 1983, pennies were about 95% copper and 5% tin and zinc. However, from 1793-1837, pennies were pure copper. If you had a penny from 1800 that had a mass of 2.

A sample of neon gas has a pressure of 2.50 atm in a 2.50 L container, at what volume will neon have a pressure of 9.68?

What type of reaction is represented by the following equation: C4H8 (g) + 602 (g) → 4CO2 (g) + 4H2O (g)

Compare the appearance and pH of the unfiltered and filtered polluted water. What conclusion can be made based on these observations?

Which statement describes the formation of our sun?

A 1.3 g sample of gold (specific heat capacity = 0.130 J/g °C) is heated using 86.9 J of energy. If the original temperature of the gold is 25.0°C, what is its final temperature?

In what applications might coal replace petroleum based fuel

How many molecules are in 7.5 mol of h2o

An electron moved from a lower energy level to a higher energy level. What most likely happened during the transition? A random amount of light was released. A fixed amount of energy was absorbed. A fixed amount of energy was released.

Solid sodium reacts violently with water, producing heat, hydrogen gas, and sodium hydroxide. How many molecules of hydrogen gas are formed when 57.1 grams of sodium are added to water?