The question is incomplete, the complete question is;
The table above summarizes data given to a student to evaluate the type of change that took place when substance X was mixed with water. The student claimed that the data did not provide enough evidence to determine whether a chemical or physical change took place and that additional tests were needed. Which of the following identifies the best way to gather evidence to support the type of change that occurred when water and Xwere mixed?
A. Measuring the melting point of the mixture of water and X
B. Adding another substance to the mixture of water and X to see whether a solid forms
C Measuring and comparing the masses of the water, X, and the mixture of water and X
D Measuring the electrical conductivities of X and the mixture of water and X
Answer:
D Measuring the electrical conductivities of X and the mixture of water and X
Explanation:
Unfortunately, I am unable to reproduce the table here. However, from the table, the temperature of the of the mixture of the solid X and water was 101.6°C. This is above the boiling point of water and way below the temperature of the solid X.
This goes a long way to suggest that there was some kind of interaction between the water and X which accounted for the observed temperature of the system of X in water.
The only way we can be able to confirm if X actually dissolved in water is to measure the conductivity of the water. dissolved solids increase the conductivity of water.
There is four stages of technological design:1. identify a problem or need.2. design a solution.3. implement, build, test the design.4. determine if the solution met the need.To design a solution is second stage of technological design.
18g is the most reasonable mass after the reaction
Answer:
The volume is 19.7 mL
Explanation:
<u>Step 1</u>: Given data
Pressure at sea level = 1.00 atm
Pressure at 50 ft = 2.47535 atm
kH for N2 in water at 25°C is 7.0 × 10−4 mol/L·atm
Molarity (M) = kH x P
<u>Step 2</u>: Calculate molarity
M at sea level:
M = 7.0*10^-4 * (1.00atm * 0.78) = 5.46*10^-4 mol/L
M at 50ft:
M = 7.0*10^-4 * (2.47535atm * 0.78) = 13.5*10^-4 mol/L
We should find the volume of N2. To find the volume whe have to find the number of moles first. This we calculate by calculating the difference between M at 50 ft and M at sea level.
13.5*10^-4 mol/L - 5.46*10^-4 mol/L = 8.04*10^-4 mol/L
Step 3: Calculate volume
P*V=nRT
with P = 1.00 atm
with V = TO BE DETERMINED
with n = 8.04*10^-4 mol/L *1L = 8.04*10^-4
with R= 0.0821 atm * L/ mol *K
with T = 25 °C = 273+25 = 298 Kelvin
To find the volume, we re-organize the formula to: V=nRT/P
V= (8.04*10^-4 mol * 0.0821 (atm*L)/(mol*K)* 298K ) / 1.00atm = 0.0197L = 19.7ml
The volume is 19.7 mL
Answer:
the correct answer is (sp3d2) (d)
Explanation:
