First convert grams to moles:
90.0g *(mole/39.997) = 2.250mole
Remember that molarity is moles per liters:
2.250mol/3L = .750 M
1) reactants: Ca + O2 (g)
2) Unbalanced equation: Ca + O2 (g) -> CaO
3) Balanced equation: 2Ca + O2 (g) -> 2CaO
Your answer is B and the element is Carbon
So what your looking for is matching isotopes. Isotopes are elements that are the same in amount of protons but different in mass meaning different number in neutrons. Because when you add the total protons and neutrons together you get your atomic mass. So this can be written as X=said element, top number above=different atomic mass, bottom number below=atomic number. Hope this help!!
Be careful because answer A has same masses but different atomic numbers so different atoms(elements)!!!
I hope my photo helps. since oxygen goes from a charge of 0 to -2, it gains electrons because electrons have a negative charge. nitrogen goes from 0 to +2 meaning that it is losing electrons to make it a positive charge.
Answer:
Depending on the context, an independent variable is sometimes called a "predictor variable", regressor, covariate, "manipulated variable", "explanatory variable", exposure variable (see reliability theory), "risk factor" (see medical statistics), "feature" (in machine learning and pattern recognition)
Explanation: