6. Positive uses of radioactive decay used by humans would not include

This is an unit conversion problem. We have to convert from cm² to km². We can do that by knowing that there are 100 cm in 1 m, and 1000 m in 1 km, so 100000 cm=1km. Knowing that we can apply the following conversion factor:

$15.9 cm^{2} * (\frac{1 km}{100000 cm} )^{2}=0.00000000159 km^{2}$

Now to convert this value to scientific notation, we have to move the decimal point to the right until we get a whole number, and the exponent of the number 10 is going to be the number of spaces we moved to the right (negative), so the final answer is:

$0.00000000159 km^{2}=1.59*10^{-9} km^{2}$

Have a nice day!

#LearnwithBrainly

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3 years ago

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barxatty [35]

1. double replacement[two of the chemical species(B and D)exchanged positions]

2. Combustion(the reaction with oxygen produced CO2 and water; products of Combustion)

3. Single replacement(only one chemical specie[B] exchanged position)

4. Combination(the two reactants formed a single product)

5. Decomposition(a compound released two constituent products)

6. 1PbCl2 + 2AgNO3 = 1Pb(NO3)2 + 2AgCl. it is a double replacement reaction since two chemical species(Chlorine(Cl) and Nitrogen(iii)oxide[NO3]) exchanged positions.

7. 1NH3 + HCL = NH4Cl. it is a combination reaction since two reactants formed a single product.

8. 2AlCl3 + 3Na2SO4 = 1Al(SO4)3 + 6NaCl. it is a double replacement reaction since two chemical species(chlorine[Cl] and sulphate[SO4]) exchanged positions.

9. 1Zn + 1S = 1ZnS. it is a combination reaction since two reactants formed a single product.

10. 1Al2(SO4)3 + 3BACl2 = 3BASO4 + 2ALCL3. it is a double replacement reaction since two chemical species(chlorine[Cl] and sulphate[SO4]) exchanged positions.

11. 1Al2S3 = 2Al + 3S. it is a decomposition reaction since a reactant released two constituent products.

12. 1H2SO4 + 1Fe = 1H2 + 1FeSO4. it is a single replacement reaction since one chemical specie(sulphate[SO4]) exchanged position.

13. C12H22O11 + 12O2 = 12CO2 + 11H2O. it is a combustion reaction since a reactant combined with oxygen to release carbon dioxide(CO2) and water(H2O).

14. 1Mg(OH)2 + 1H2SO4 = 1MgSO4 + 2H2O. it is a double replacement reaction since two chemical species(hydroxide[OH] and sulphate[SO4]) exchanged positions.

15. 2NaOH + 1CuSO4 = Na2SO4 + Cu(OH)2. it is a double replacement reaction since two chemical species(hydroxide[OH] and sulphate[SO4]) exchanged positions.

16. 1C4H12 + 7O2 = 6H2O + 4CO2. it is a combustion reaction since a reactant combined with oxygen to release carbon dioxide(CO2) and water(H2O).

17. 4Fe + 3O2 = 2Fe2O3. it is a combination reaction since two reactants formed a single product.

18. 1Mg3(PO4)2 + 3H2 = 3Mg + 2H3PO4. it is a single replacement reaction since one chemical specie(phosphate[PO4]) exchanged position.

19. 2NH4NO3 = 2N2O + 4H2O. it is a decomposition reaction since a reactant released two constituent products.

20. 1Cl2 + 2KBr = 2KCl + 1Br2. it is a single replacement reaction since one chemical specie(potassium[K]) exchanged position.

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1 year ago