Which of the following is a base?
vinegar
lemon juice
stomach acid
baking soda
baking soda
What feature makes water a polar molecule?
A water molecule is positively charged.
A water molecule is negatively charged.
The ends of the water molecule have opposite electrical charges.
The middle of the water molecule contains opposing charges.
The ends of the water molecule have opposite electrical charges.
Which is the term for numbers that appear in the chemical formulas of some compounds?
subscripts
coefficients
square roots
exponents
subscripts
How does the composition of a water molecule affect its charge?
It makes the molecule nonpolar.
It makes the molecule a positive ion.
It makes the molecule polar.
It makes the molecule a negative ion.
It makes the molecule polar.
Which is true of hydroxide ions?
They dissociate to form protons.
They are not found in pure water.
They have a negative charge.
They contain two hydrogen atoms.
They have a negative charge.
What kind of change causes iron to rust?
freezing reaction
physical change
chemical change
state change