Cevaplı Hemşirelik giriş sınavları için kimya çalışma kâğıdı

Where do the mole ratios used in stoichiometry come from?

1. AThe subscripts in each formula
2. BThe molar masses of the reactants
3. CThe physical states of the substances
4. DThe coefficients of the balanced equation

What does the law of conservation of mass state?

1. AMass is lost as heat in every reaction
2. BMass is neither created nor destroyed in a chemical reaction
3. CGases have no mass
4. DThe mass of products is always greater than the mass of reactants

What is the formula of methane, the main gas in natural gas?

1. ACO₂
2. BC₂H₆
3. CCH₂
4. DCH₄

A reaction has ΔH = −890 kJ/mol. What does the negative sign tell you?

1. AThe reaction is exothermic
2. BThe reaction is endothermic
3. CThe reaction is at equilibrium
4. DThe reaction needs a catalyst

How should the volume of water in a graduated cylinder be read?

1. AAt eye level, from the bottom of the curved surface (meniscus)
2. BFrom above the cylinder, at the top edge of the curved surface
3. CAt any angle, from the middle of the cylinder
4. DFrom below, at the highest point the water touches the glass

What is the shape of a water molecule?

1. ALinear
2. BTetrahedral
3. CBent
4. DFlat triangle

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. BCarbon and oxygen have the same electronegativity
3. CThe bonds are ionic, not covalent
4. DCarbon has lone pairs that cancel the dipoles

Alkanes follow the general formula CₙH₂ₙ₊₂. What is the formula of the alkane with 4 carbon atoms?

1. AC₄H₁₀
2. BC₄H₈
3. CC₄H₁₂
4. DC₄H₆