Question 7 (2 points)

Which type of volcanic mountain has wide, gentle slopes? rift shield composite cinder cone

JulijaS [17]

Answer:

b) sheild

Explanation:

i just did the test

6 0

2 years ago

Read 2 more answers

Calculate the pH of a solution prepared by dissolving 0.370 mol of formic acid (HCO2H) and 0.230 mol of sodium formate (NaCO2H)

Veronika [31]

The question is incomplete, here is the complete question:

Calculate the pH of a solution prepared by dissolving 0.370 mol of formic acid (HCO₂H) and 0.230 mol of sodium formate (NaCO₂H) in water sufficient to yield 1.00 L of solution. The Ka of formic acid is 1.77 × 10⁻⁴

a) 2.099

b) 10.463

c) 3.546

d) 2.307

e) 3.952

<u>Answer:</u> The pH of the solution is 3.546

<u>Explanation:</u>

We are given:

Moles of formic acid = 0.370 moles

Moles of sodium formate = 0.230 moles

Volume of solution = 1 L

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

To calculate the pH of acidic buffer, we use the equation given by Henderson Hasselbalch:

$pH=pK_a+\log(\frac{[salt]}{[acid]})$

$pH=pK_a+\log(\frac{[HCOONa]}{[HCOOH]})$

$pK_a$ = negative logarithm of acid dissociation constant of formic acid = 3.75

$[HCOONa]=\frac{0.230}{1}$

$[HCOOH]=\frac{0.370}{1}$

pH = ?

Putting values in above equation, we get:

$pH=3.75+\log(\frac{0.23/1}{0.37/1})\\\\pH=3.54$

Hence, the pH of the solution is 3.546

5 0

3 years ago

150 ml of 0.1 m naoh is added to 200 ml of 0.1 m formic acid, and water is added to give a final volume of 1 l. what is the ph o

N76 [4]

Number of moles of NaOH = V(NaOH) * M(NaOH)= 0.150 L * 0.1 moles/L = 0.015 moles

Number of moles of formic acid, HCOOH = V(HCOOH) * M(HCOOH) = 0.200 L * 0.1 moles/L = 0.020 moles

Here, the limiting reagent is NaOH

The reaction is represented as:

HCOOH + NaOH ↔HCOONa + H2O

Moles of HCOONa formed = Moles of the limiting reagent, NaOH = 0.015 moles

Moles of HCOOH remaining = 0.020-0.015 = 0.005 moles

Total final volume is given as 1 L

Therefore: [HCOOH] = 0.005 moles/1 L = 0.005 M

[HCOONa] = 0.015/1 = 0.015 M

pKa of HCOOH = 3.74

As per Henderson-Hasselbalch equation

pH = pka + log[HCOONa]/[HCOOH] = 3.74+log[0.015/0.005] = 4.22

Therefore, pH of the final solution = 4.22

3 0

3 years ago

If the total mass of the products of a reaction is 90 gram, what was the total mass of the reactants

Marizza181 [45]

90 grams due to laws of conservation of mass. Output mass = input mass. Mass can never be created or destroyed.

4 0

3 years ago

Choose all that apply. What tools do scientists use to make decisions when employing reasoning skills?

andrey2020 [161]

Answer:

B, (logic) D (knowledge)

Explanation:

Problem solving refers to the ability to figure out an answer to a question. The question can be general, such as how to design an experiment, or it can be more specific, such as how to calculate speed (its distance divided by time). Reasoning is closely related to problem solving. When scientists reason, they use logic and knowledge to make conclusions and decisions. The processes of reasoning and problem solving are usually more educational than the answer. Figuring something out is a wonderful workout for your brain.

(got this from the source)

Hope this helps!!!

7 0

3 years ago