Chemistry help pelase?

1. Which of the following is not an example of a model?


A. a floor lamp


B. a globe


C. a road map


D. a wind tunnel





2. A 1-g sample of the compound hydrogen chloride was analyzed and found to be 2.74 percent hydrogen and 97.3 percent chlorine. What percentage of hydrogen is present in a 2-g sample of hydrogen chloride?


A. 1.37%


B. 2.74%


C. 5.48%


D. 97.3%





3. The atomic number of an element whose atoms have 9 electrons and 10 neutrons is?


A. 9


B. 19


C. 1


D. 18





4.One isotope of carbon has 6 protons and 6 neutrons. The number of protons and neutrons of a second isotope of carbon would be?


A. 7 and 6


B. 6 and 7


C. 7 and 7


D. 6 and 6





5. If 9.0 g of water contain 1.0 g of hydrogen, what mass of oxygen is contained in 36 g of water?


A. 4.0 g


B. 8.0 g


C. 10.0


D. 32 g

Chemistry help pelase?
1 - A


2 - B


3 - A


4 - B


5 - D





there ya go
Reply:1. a floor lamp


2. In 100 g of HCl, there are 97.3 g of Cl and


2.74 g of H, accordinhg to the percentages.


Therefore, ANY amount of HCl will contain


2.74% H.


3. A; If the element has 9 electrons, it also has


9 protons. Any element with 9 protons is


fluorine, atomic number 9 in the periodic


table.


4. B; 6 protons and 7 neutrons. The number of


neutrons can vary but it MUST contain 6


protons to still be carbon.


5. D; If 9.0 g of water contain 1.0 g of H, the


other 8.0 g must be oxygen since water is


H2O. So


36 g H2O x (8.0 g O2 / 9.0 g H2O) = 32 g