// Numbas version: finer_feedback_settings
{"name": "Solutions 1", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false, "typeendtoleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"statement": "<p>Answer the following questions. Please enter your answers as decimals, not as fractions. Enter your answers to 2 decimal places.</p>\n<p>If you would like to see how to do this question, click on 'Reveal answers' at the bottom of the page.</p>", "ungrouped_variables": ["a", "c", "b", "d"], "name": "Solutions 1", "variable_groups": [], "variablesTest": {"maxRuns": "100", "condition": ""}, "extensions": [], "functions": {}, "advice": "<p>To answer these questions we use the formula</p>\n<p style=\"text-align: center;\">$\\dfrac{\\text{number of moles of substance}}{\\text{volume of liquid (in litres)}} = \\text{concentration (in mol/L)}$.</p>\n<h4>a)&nbsp;</h4>\n<p>$\\var{a}$ mole(s) of a substance are dissolved in $\\var{b}$ litre(s) of a liquid to make a solution. What is the concentration of the solution in M (mol/L)?</p>\n<p>Solution:</p>\n<p>Putting our numbers into the formula, we find that the concentration is</p>\n<p style=\"text-align: center;\">$\\begin{align}\\dfrac{\\var{a}}{\\var{b}} &amp; = \\var{a / b} M \\\\ &amp; = \\var{precround((a / b), 2)} M \\text{ to 2 d.p.} \\end{align}$</p>\n<h4 style=\"text-align: left;\">b)</h4>\n<p style=\"text-align: left;\">$\\var{0.25 * c}$ mole(s) of a substance are dissolved in $\\var{250 * d}$ml of a liquid to make a solution. What is the concentration of the solution in M (mol/L)?</p>\n<p style=\"text-align: left;\">Solution:</p>\n<p style=\"text-align: left;\">The formula uses the volume of liquid in litres so we first have to convert $\\var{250 * d}$ml to a volume in litres. There are $1000$ml in 1L so $\\var{250 * d}$ml is equal to&nbsp;</p>\n<p style=\"text-align: center;\">$\\dfrac{\\var{250 * d}}{1000} = \\var{250 * d / 1000}L$.</p>\n<p>Putting our numbers into the formula, we find that the concentration is</p>\n<p></p>\n<p style=\"text-align: center;\">$\\begin{align}\\dfrac{\\var{0.25 * c}}{\\var{250 * d / 1000}} &amp; = \\var{(0.25 * c) / (250 * d / 1000)} M \\\\ &amp; = \\var{precround(((0.25 * c) / (250 * d / 1000)), 2)} M \\text{ to 2 d.p.} \\end{align}$</p>", "metadata": {"licence": "Creative Commons Attribution 4.0 International", "description": "<p>Practice calculating concentration of solutions</p>"}, "preamble": {"css": "", "js": ""}, "tags": ["concentration", "molarity", "solutions"], "variables": {"b": {"name": "b", "templateType": "anything", "group": "Ungrouped variables", "description": "", "definition": "random(1..9)"}, "a": {"name": "a", "templateType": "anything", "group": "Ungrouped variables", "description": "", "definition": "random(1..9)"}, "d": {"name": "d", "templateType": "anything", "group": "Ungrouped variables", "description": "", "definition": "random(1..8)"}, "c": {"name": "c", "templateType": "anything", "group": "Ungrouped variables", "description": "", "definition": "random(1..10)"}}, "rulesets": {}, "parts": [{"variableReplacementStrategy": "originalfirst", "type": "gapfill", "showFeedbackIcon": true, "showCorrectAnswer": true, "scripts": {}, "gaps": [{"precision": "2", "precisionMessage": "You have not given your answer to the correct precision.", "minValue": "(a / b) - 0.005", "type": "numberentry", "correctAnswerStyle": "plain", "showFeedbackIcon": true, "showCorrectAnswer": true, "maxValue": "(a / b) + 0.005", "precisionType": "dp", "precisionPartialCredit": 0, "mustBeReduced": false, "marks": 1, "notationStyles": ["plain", "en", "si-en"], "variableReplacementStrategy": "originalfirst", "strictPrecision": false, "allowFractions": false, "scripts": {}, "showPrecisionHint": false, "mustBeReducedPC": 0, "correctAnswerFraction": false, "variableReplacements": []}], "prompt": "<p>$\\var{a}$ mole(s) of a substance are dissolved in $\\var{b}$ litre(s) of a liquid to make a solution. What is the concentration of the solution in M (mol/L)?</p>\n<p>[[0]] M</p>", "variableReplacements": [], "marks": 0}, {"variableReplacementStrategy": "originalfirst", "type": "gapfill", "showFeedbackIcon": true, "showCorrectAnswer": true, "scripts": {}, "gaps": [{"precision": "2", "precisionMessage": "You have not given your answer to the correct precision.", "minValue": "(0.25 * c) / (250 * d / 1000) - 0.005", "type": "numberentry", "correctAnswerStyle": "plain", "showFeedbackIcon": true, "showCorrectAnswer": true, "maxValue": "(0.25 * c) / (250 * d / 1000) + 0.005", "precisionType": "dp", "precisionPartialCredit": 0, "mustBeReduced": false, "marks": 1, "notationStyles": ["plain", "en", "si-en"], "variableReplacementStrategy": "originalfirst", "strictPrecision": false, "allowFractions": false, "scripts": {}, "showPrecisionHint": false, "mustBeReducedPC": 0, "correctAnswerFraction": false, "variableReplacements": []}], "prompt": "<p>$\\var{0.25 * c}$ mole(s) of a substance are dissolved in $\\var{250 * d}$ml of a liquid to make a solution. What is the concentration of the solution in M (mol/L)?</p>\n<p>[[0]] M</p>", "variableReplacements": [], "marks": 0}], "type": "question", "contributors": [{"name": "Jamie Antoun", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/266/"}]}]}], "contributors": [{"name": "Jamie Antoun", "profile_url": "https://numbas.mathcentre.ac.uk/accounts/profile/266/"}]}