A homogenous mixture is uniform and thus hard to recognize as a mixture. An example is water.
To help you answer this question, you can search a sample reaction in the internet for hydroboration-oxidation. Take a look at the attached picture. The sample reaction is shown at the top. We can deduce that the original compound must be an alkene. Following the pattern, compound a must be 2-methylbutene as shown in the picture.
Answer:- Heat lost by the metal is 279.45 cal.
Solution:- This type of problems are solved by using the concept, heat given = - heat taken
Metal temperature is decreasing from 45.00 degree C to 11.08 degree C. It means the heat is lost by the metal and this heat lost by metal is gained by water and the calorimeter to raise their temperature.
the equation we use is, 
.
where, q is the heat energy, m is mass, c is specific heat and 
is change in temperature.
Combined mass of calorimeter and water is 250.0 g and the specific heat is 
.
for calorimeter and water (combined) = 11.08 - 10.00 = 1.08 degree C
for metal = 11.08 - 45.00 = -33.92 degree C
let's plug in the values in the above equation and calculate heat gained by combined system.
q=250.0g*\frac{1.035cal}{g.^0C}*1.08^0C
q = 279.45 cal
So, the heat lost by the metal is 279.45 cal.
Answer:
A. an observation
Explanation:
Because by saying that the leaf is green that is an observation on the leaf to tell what color it is.
Have a nice day/night :)
The number of mole of HCl needed for the solution is 1.035×10¯³ mole
<h3>How to determine the pKa</h3>
We'll begin by calculating the pKa of the solution. This can be obtained as follow:
- Equilibrium constant (Ka) = 2.3×10¯⁵
- pKa =?
pKa = –Log Ka
pKa = –Log 2.3×10¯⁵
pKa = 4.64
<h3>How to determine the molarity of HCl </h3>
- pKa = 4.64
- pH = 6.5
- Molarity of salt [NaZ] = 0.5 M
- Molarity of HCl [HCl] =?
pH = pKa + Log[salt]/[acid]
6.5 = 4.64 + Log[0.5]/[HCl]
Collect like terms
6.5 – 4.64 = Log[0.5]/[HCl]
1.86 = Log[0.5]/[HCl]
Take the anti-log
0.5 / [HCl] = anti-log 1.86
0.5 / [HCl] = 72.44
Cross multiply
0.5 = [HCl] × 72.44
Divide both side by 72.44
[HCl] = 0.5 / 72.4
[HCl] = 0.0069 M
<h3>How to determine the mole of HCl </h3>
- Molarity of HCl = 0.0069 M
- Volume = 150 mL = 150 / 1000 = 0.15 L
Mole = Molarity x Volume
Mole of HCl = 0.0069 × 0.15
Mole of HCl = 1.035×10¯³ mole
<h3>Complete question</h3>
How many moles of HCl need to be added to 150.0 mL of 0.50 M NaZ to have a solution with a pH of 6.50? (Ka of HZ is 2.3 x 10 -5 .) Assume negligible volume of the HCl
Learn more about pH of buffer:
brainly.com/question/21881762
