CHM083 TOPIC 4

Select the correct definition for solution.

• Substance dissolved in solvent

• A homogeneous mixture of two or more substances

• A mixture contains two or more substances that are not chemically combined

• Substance in which solute dissolves

What is the molarity of 5.30 g of Na2CO3 dissolved in 400.0 mL solution?

• 0.105 M

• 0.125 M

• 0.25 M

• 0.225 M

How much NaOH (in grams) is needed to prepare 546 mL of solution with a concentration of 0.347 M?

• 0.189 g

• 7.578 g

• 134.862 g

• 239.141 g

How many moles of Ca(NO3)2 are there in 75 mL of 0.25 M solution?

• 0.0188 mol

• 0.02 mol

• 0.0321 mol

• 0.044mol

You have a 0.5 M MgSO₄ stock solution available. Calculate the volume of the stock solution needed to make 2.0 L of 0.20 M MgSO₄.

• 0.8 L

• 0.1 L

• 5.0 L

• 0.5 L

You have 505 mL of a 0.125 M HCl solution and you want to dilute it to exactly 0.100 M. How much distilled water should you add?

• 631.25 mL

• 404.00 mL

• 126.25 mL

• 101.00 mL

Calculate the molarity of solution prepared when 100 ml of a 6.0 M KCl solution is diluted to a volume of 5.0 L

• 0.3 M

• 3.0 M

• 1.2 M

• 0.12 M

What happens in a neutralization reaction?

• The hydrogen ions from the acid and the hydroxide ions from the base come together to form water.

• The hydrogen ions from the base and the hydroxide ions from the acid come together to form water.

• A substance's pH is increased to a value greater than 7.

• A solution of a known concentration and volume is added until the reaction is completed.

The following neutralization reaction occurs in the classroom.

HCl + KOH → H₂O + KCl

In this acid-base titration, it was found that 25.00 mL of 0.50 M KOH was used to neutralise an unknown molarity of 15.0 mL HCl. Determine the molarity of HCl.

• 0.80 M

• 1.20 M

• 5.20 M

• 12.50 M

In an acid-base titration, it was found that 37.00 mL of 0.40 M NaOH was neutralised by an unknown volume of 0.70 M H₂S0₄. Determine the colour change of the solution when the titration reach the end point if the indicator used was methyl orange.

• Yellow to orange

• Orange to yellow

• Pink to colourless

• Red to blue