Answer: 127 (3.s.f)
Explanation:
Boyle's law states that Volume x pressure = constant
Therefore let's first find the constant: 45 x 1900 = 85500
Then lets plug 675 ml and 85500 into the equation above:
675 x C = 85500
C = 127 (3 s.f.)
The correct answer to this question is this one:
Assuming all the barium bromide dissolved (which it should), the concentration of BaBr2 in solution should be zero: it should all dissociate into Ba+2 and 2Br- ions.
Turn those grams of BaBr2 into moles of BaBr2, then divide by the volume to get the concentration.
Recognize that every formula unit of BaBr2 has one ion of Ba+2, and 2 ions of Br-1. That means that when this substance dissociates, you'll get one concentration of Ba+2 ions, and a concentration of Br- ions TWICE as large. Whatever the concentration of Ba+2 ions is that you calculate, double it for the conentration of the Br-1 ion.
Answer:
-1.78 V
Explanation:
There are several rules required to calculate the cell potential:
- given standard cell potential, we may reverse the equation: the products of a given reaction become our reactants, while reactants become our products in the reversed equation. For a reversed equation, we change the sign of the cell potential to the opposite sign;
- if we multiply the whole equation by some number, this doesn't influence the cell potential value. It only produces a different expression in the equilibrium constant.
That said, notice that the initial reaction with respect to the final reaction is:
- reversed: chromium(III) cation and chloride anion become our reactants as opposed to the products in the initial reaction, so we change the sign of the cell potential to a negative value of -1.78 V;
- each coefficient is multiplied by a fraction of . It doesn't influence the value of the cell potential.
Thus, we have a cell of E = -1.78 V.
Answer:
Open spaces in water's solid structure makes its solid state less dense than its liquid state.
Explanation:
- Water unlike other liquids is special. It contracts when cooled, down to a temperature of 4°C but thereafter begins to expand as it reaches 0°C and turns into ice.
- This property is useful for the preservation of marine life in very cold temperatures. During winter, the surface water in water lakes and rivers starts cooling. Upon reaching the temperature of 4°C, the surface water descends to the bottom as it denser.
- This help in the maintenance of temperature of the water at the bottom at 4°C. It is in this layer that marine life is sustained.