What is the weight percent of each o in sio^2?

53.2%

Explanation:

Mass of Si in 1 mol SiO2 =28.1g

Mass of O  in 1 mol SiO2 =16x2g= 32g

Mass of compound= 28.1+32=60.1

% by mass = (mass of element/mass of compound) x 100

% by mass of oxigen= (32g/60.1) x 100

% by mass of oxigen= 53.2%

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d. stage 4

explanation:

the existence of some kind of demographic transition is widely accepted in the social sciences because of the well-established historical correlation linking dropping fertility to social and economic development.[1] scholars debate whether industrialization and higher incomes lead to lower population, or whether lower populations lead to industrialization and higher incomes. scholars also debate to what extent various proposed and sometimes inter-related factors such as higher per capita income,lower mortality, old-age security, and rise of demand for human capital are involved.[2]

the roman republic began to expand when rome fought the punic wars and defeated carthage. the punic wars refer to the series of 3 wars fought among rome and carthage, before it ended in carthage's defeat.