// Numbas version: exam_results_page_options {"name": "Rearranging concentration formula for mass (numeric)", "extensions": [], "custom_part_types": [], "resources": [], "navigation": {"allowregen": true, "showfrontpage": false, "preventleave": false}, "question_groups": [{"pickingStrategy": "all-ordered", "questions": [{"functions": {}, "ungrouped_variables": ["chem"], "name": "Rearranging concentration formula for mass (numeric)", "tags": ["concentration", "ephlth", "nursing"], "preamble": {"css": "", "js": ""}, "advice": "", "rulesets": {}, "parts": [{"stepsPenalty": "1", "prompt": "

A solution has a percentage concentration of {ansb} % w/v of {chem}. It was made by mixing {millb} mL of solvent and  [] grams of {chem}.

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Given \$\\text{percentage concentration (w/v)}=\\dfrac{\\text{mass of solute (g)}}{\\text{volume of solvent (mL)}}\\times \\text{100},\$

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we can substitute our values for percentage concentration and volume of solvent and rearrange to get the value of 'mass of solute (g)'.

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\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
 $\\text{percentage concentration (w/v)}$ $=$ $\\dfrac{\\text{mass of solute (g)}}{\\text{volume of solvent (mL)}}\\times \\text{100}$ $\\var{ansb} \\text{ % (w/v)}$ $=$ $\\dfrac{\\text{mass of solute (g)}}{\\var{millb} \\text{ mL}}\\times 100$ $\\dfrac{\\var{ansb} \\text{ % (w/v)}}{100}$ $=$ $\\dfrac{\\text{mass of solute (g)}}{\\var{millb} \\text{ mL}}\\times \\dfrac{100}{100}$ $\\dfrac{\\var{ansb} \\text{ % (w/v)}}{100}$ $=$ $\\dfrac{\\text{mass of solute (g)}}{\\var{millb} \\text{ mL}}$ $\\dfrac{\\var{ansb} \\text{ % (w/v)}}{100}\\times \\var{millb} \\text{ (mL)}$ $=$ $\\dfrac{\\text{mass of solute (g)}}{\\var{millb} \\text{ mL}}\\times \\var{millb} \\text{ mL}$ $\\var{gramsb} \\text{ (g)}$ $=$ $\\text{mass of solute (g)}$
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https://en.wikipedia.org/wiki/Mass_concentration_(chemistry)#Usage_in_biology

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