Answer:
When two substances are mixed together, a color change is observed. This observation is not enough evidence that there is a chemical reaction happening because color changes are not indicators of chemical reaction:
Is their a picture or something?
15/70 =3/14 miles per minute = 0.21 miles a minute. One mile in about 5 minutes. Sarah is shifting, I think (faster than me)
Answer:
a
b

Explanation:
From the question we are told that
The pressure of the manometer when there is no gas flow is 
The level of mercury is 
The drop in the mercury level at the visible arm is 
Generally when there is no gas flow the pressure of the manometer is equal to the gauge pressure which is mathematically represented as

Here
is the density of mercury with value 
and
is the difference in the level of gas in arm one and two
So


Generally the height of the mercury at the arm connected to the pipe is mathematically represented as

=> 
Generally from manometry principle we have that
![P_G + \rho * g * d - \rho * g * [h - (h_m + d)] = 0](https://tex.z-dn.net/?f=P_G%20%2B%20%5Crho%20%2A%20g%20%20%2A%20d%20%20%20-%20%20%5Crho%20%2A%20%20g%20%20%2A%20%5Bh%20-%20%28h_m%20%2B%20d%29%5D%20%3D%200)
Here
is the pressure of the gas
![P_G +13.6 *10^{3} * 9.8 * 0.039 - 13.6 *10^{3} * 9.8 * [0.950 - (0.148 + 0.039)] = 0](https://tex.z-dn.net/?f=P_G%20%2B13.6%20%2A10%5E%7B3%7D%20%2A%209.8%20%20%2A%200.039%20%20%20%20-%20%2013.6%20%2A10%5E%7B3%7D%20%20%2A%20%209.8%20%20%2A%20%5B0.950%20-%20%280.148%20%2B%200.039%29%5D%20%3D%200)

converting to psig