Answer:
Newton's 2nd Law (Option B)
Explanation:
Answer:
Increase in the concentration of the reactants (vinegar and baking soda) leads to an increase in the rate of reaction (more volume of CO2 is evolved within a shorter time)
Explanation:
The chemical reaction between baking soda and vinegar in water is shown in the chemical reaction equation below;
NaHCO3(aq) + CH3COOH(aq) ----->CO2(g) + H2O(l) + CH3COONa(aq)
The chemical name of baking soda is sodium bicarbonate (NaHCO3) while vineager is a dilute acetic acid (CH3COOH) solution. This reaction provides a very easy set up in which we can study the effect of concentration on the rate of chemical reaction.
We must have it behind our minds that increase in the concentration of reactant species increases the rate of chemical reaction. Secondly, the rate of the reaction between baking soda and vinegar can be monitored by observing the volume of CO2 evolved and how quickly it evolves from the reaction mixture.
We can now postulate a hypothesis which states that; 'increase in the concentration of the reactants (vinegar and baking soda) leads to an increase in the rate of reaction (more volume of CO2 is evolved within a shorter time).'
If we go ahead to subject this hypothesis to experimental test, it will be confirmed to be true because a greater volume of CO2 will be evolved within a shorter time as the concentration of the reactants increases.
Answer: m= 0.69 m or mol/kg
Explanation: Molality is expressed as moles per unit kilograms of solvent or m= n / kg
First convert 25.0 g NaCl to moles
25.0 g NaCl x 1 mole NaCl / 58 g NaCl
= 0.43 moles NaCl
Next convert 625 g H2O to kilograms
625 g H2O x 1 kg / 1000 g H2O
= 0.625 kg H2O
Substitute the values in the formula
m = n / kg
= 0.43 mole NaCl / 0.625 kg
= 0.69 m or mole / kg
89.1% Au
The molar mass of Au2O3 is 2(196.97) + 3(16.00) = 441.94 g/mol
The mass percent of Au is therefore 2(196.97) / 441.94, which is 393.94/441.94 = 0.891 —> 89.1%
