Elements are substances that cannot be broken down or . Compounds are substances as well that cannot be broken down but can be . Homogeneous mixtures are not bonded and are throughout. A technique a homogeneous mixture can be separated is . Heterogeneous mixtures are not throughout and each component of the mixture maintains its properties. A technique to separate heterogeneous mixtures is .

The molecular formula for caffeine is cshion402. which of the following elements is not found in caffeine?

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next

Inside a flashbulb, oxygen surrounds a thin coil of magnesium. when the flashbulb is set off, a chemical reaction takes place in which magnesium combines with oxygen to form magnesium oxide. which of the chemical equations matches the reaction above? a. mg + o2 mgo2 + energy b. 2mg + o mg2o + energy c. 2mg + o2 2mgo + energy d. mg + o mgo + energy