Answer:
~1.417M
Explanation:
Molarity=(number of moles of solute)/(litres of solution)
In this case, we need to find moles of potassium bromide.
Mass=25.3g
Molar mass= 119g/mol
moles=(mass/molar mass)
=(25.3)/(119)
=0.2126moles of potassium bromide
Molarity=(0.2126)/(150/1000)
~1.417M
Hope this helps:)
Answer: (2) decreasing the concentration of HCl(aq) to 0.1 M
Explanation: Rate of a reaction depends on following factors:
1. Size of the solute particles: If the reactant molecules are present in smaller size, surface of particles and decreasing the size increases the surface area of the solute particles. Hence, increasing the rate of a reaction.
2. Reactant concentration: The rate of the reaction is directly proportional to the concentration of reactants.
3. Temperature: Increasing the temperature increases the energy of the molecules and thus more molecules can react to give products and rate increases.
(1) Increasing the initial temperature to 25°C will increase the reaction rate.
(2) Decreasing the concentration of HCl(aq) to 0.1 M will decrease the reaction rate due to lesser concentration.
(3) Using 1.2 g of powdered Mg will increase the reaction rate due to large surface area.
(4) Using 2.4 g of Mg ribbon will increase the reaction rate due to high concentration of reactants.
Answer: d) -705.55 kJ
Explanation:
Heat of reaction is the change of enthalpy during a chemical reaction with all substances in their standard states.
Reversing the reaction, changes the sign of 
On multiplying the reaction by 
, enthalpy gets half:
Thus the enthalpy change for the given reaction is -705.55kJ
Answer:
The answer is B
Explanation:
Less air means less air pressure. At a certain point, there is very little air pressure to push against the outward pressure of the helium inside the balloon. It will then expand until the rubber breaks, and the balloon bursts
<span>Carbon (C) is most likely to form covalent bonds with Beryllium (Be) or Sodium (Na) because they are both metals and covalent bonds are metals that share their valence electrons with the gases / non-metals to get to the stable octet. Krypton is a gas and Selenium is a metalloid</span>
