The percentage of nitrogen in ammonia is _______________%
Which of the following potassium fertilizers are more useful for
horticultural crops tobacco and potatatoes.
What impurity in steel can cause ted shortness which means the steel
becomes unworkable at high temperature.
What is a coal that has been previously burned in an oxygen poor
environment?
Steel is an alloy of iron and carbon with limits on the amount of
carbon to less than _______ percent.
Iron is said to be abundant in nature. About how many percent of the
earth’s crust is iron.
