Chemia na egzaminy wstępne na pielęgniarstwo: karta pracy z odpowiedziami

How many moles of oxygen atoms are in 1 mole of carbon dioxide, CO₂?

1. A0,5
2. B2
3. C1
4. D3

What does the rate of a reaction measure?

1. AHow quickly reactants are used up or products are formed
2. BHow much energy the final products contain
3. CHow much product forms in total by the end
4. DHow hot the reaction gets

What is the half-life of a radioactive isotope?

1. AThe time taken for the mass of a sample to double in size
2. BHalf the time it takes for all the atoms to decay
3. CThe time taken for half of the radioactive atoms in a sample to decay
4. DHalf the number of protons in the nucleus

Why is a carbon dioxide extinguisher effective on many fires?

1. ACO₂ is denser than air and pushes oxygen away from the fire
2. BCO₂ adds oxygen to cool the flames
3. CCO₂ is a liquid that soaks into the fuel
4. DCO₂ reacts chemically with the fuel to make it non-flammable

A room is at 25 °C. What is this temperature in kelvin?

1. A298 K
2. B77 K
3. C248 K
4. D−248 K

When a nucleus emits an alpha particle, how do its mass number and atomic number change?

1. ANeither changes
2. BMass number falls by 4 and atomic number falls by 2
3. CMass number stays the same and atomic number rises by 1
4. DMass number falls by 2 and atomic number falls by 4

Each C=O bond in carbon dioxide is polar, yet the CO₂ molecule is nonpolar. Why?

1. AThe molecule is linear, so the two bond dipoles cancel out
2. BThe bonds are ionic, not covalent
3. CCarbon has lone pairs that cancel the dipoles
4. DCarbon and oxygen have the same electronegativity

Jon ma 12 protonów i 10 elektronów. Czym jest?

1. AMg²⁺
2. BNa⁺
3. CNe
4. DMg²⁻