You want to test the effect of soil acidity on plant growth. Which of the following is an example of a controlled experiment to test this? O A. The plant type soil acidity amount of light and amount of water are all varied and studied in a laboratory.
O B. The soil acidity of plants in a garden that get light and water from their surroundings is increased after the plants grow to a height of 100 cm.
O C. The plant type amount of light and amount of water are kept constant well so acidity is varied for plants in a greenhouse.
O D. Soil acidity in height of plants growing in 10m^2 yard are measure twice in July and twice in August.

Acompound contains c, h, and o atoms. when 1.130 g of the compound is burned in oxygen, 1.064 g co2 and 0.3631 g h2o are produced. what is the empirical formula of this compound?

An atom of lithium-7 has an equal number of(1) electrons and neutrons(2) electrons and protons(3) positrons and neutrons(4) positrons and protons

The two naturally occurring isotopes of chlorine are 35cl (34.969 amu, 75.77%) and 37cl (36.966 amu, 24.23%). the two naturally occurring isotopes of bromine are 79br (78.918 rm amu, 50.69%) and 81br (80.916 amu, 49.31%). chlorine and bromine combine to form bromine monochloride, brcl. 1. how many peaks will be present in a mass spectrum for brcl? the four combinations of molecule possible given these four isotopes are: 81br37cl, 81br35cl, 79br37cl, and 79br35cl. 2. what are the masses of the four different brcl molecules? express the masses using six significant figures, in decreasing numeric order (highest to lowest), separated by commas.