Since the atomic number of calcium is 20. The number of protons is also 20.
<span>Those characteristic belong to an ionic compountd. Ionic compounds have strong bonds between their atoms (ionic bond is the strongest molecular bond) which conferes this kind of compounds high melting point, wich 9811 K is. Ionic compounds do not transmit current, because they do not have free electrons, like metals do, then they are poor conductors as solid. Ionic compounds dissolve in water into ions which are charges that can move, becoming then good conductors. The structure of ionic compound is a net of cristals which make them hard and brittle. Then, the answer i s option (4) an ionic compound.</span>
Answer:
4.77 is the pH of the given buffer .
Explanation:
To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:
![pH=pK_a+\log(\frac{[salt]}{[acid]})](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%28%5Cfrac%7B%5Bsalt%5D%7D%7B%5Bacid%5D%7D%29)
![pH=-\log[K_a]+\log(\frac{[salt]}{[acid]})](https://tex.z-dn.net/?f=pH%3D-%5Clog%5BK_a%5D%2B%5Clog%28%5Cfrac%7B%5Bsalt%5D%7D%7B%5Bacid%5D%7D%29)
![pH=-\log[K_a]+\log(\frac{[CH_3CH_2COONa]}{[CH_3CH_2COOH]})](https://tex.z-dn.net/?f=pH%3D-%5Clog%5BK_a%5D%2B%5Clog%28%5Cfrac%7B%5BCH_3CH_2COONa%5D%7D%7B%5BCH_3CH_2COOH%5D%7D%29)
We are given:
= Dissociation constant of propanoic acid = 
![[CH_3CH_2COONa]=0.254 M](https://tex.z-dn.net/?f=%5BCH_3CH_2COONa%5D%3D0.254%20M)
![[CH_3CH_2COOH]=0.329 M](https://tex.z-dn.net/?f=%5BCH_3CH_2COOH%5D%3D0.329%20M)
pH = ?
Putting values in above equation, we get:
![pH=-\log[1.3\times 10^{-5}]+\log(\frac{[0.254 M]}{[0.329]})](https://tex.z-dn.net/?f=pH%3D-%5Clog%5B1.3%5Ctimes%2010%5E%7B-5%7D%5D%2B%5Clog%28%5Cfrac%7B%5B0.254%20M%5D%7D%7B%5B0.329%5D%7D%29)
pH = 4.77
4.77 is the pH of the given buffer .
Answer:
La respuesta a tu pregunta esta abajo.
Explanation:
Cuando un barco navega en un río en el sentido de la corriente, la velocidad que lleva más el impulso que le proporciona la corriente, hace que avance más rápido llegando más pronto a su destino sin tanto esfuerzo del motor. Por lo que gastaría una menor cantidad de combustible.
Cuando el barco se desplaza en sentido contrario a la corriente del motor, la corriente del río hace que su desplazamiento neto sea menor ya que el barco avanza y el río lo regresa un tramo y el esfuerzo del motor el mayor.
En estas condiciones aunque el barco tenga que recorrer la misma distancia que en el caso anterior, en realidad debería sumarse la distancia que lo regresa la corriente y por lo tanto el combustible gastado sera mayor.
Answer:
B
Explanation:
The oxidation state is present in metals that have multiple oxidation states. Most transition metals have multiple oxidation states. Such as, Iron(II) and Iron (III).
