JohnS
Moderator
Last Activity: Yesterday, 05:07 PM
Joined: 12-20-2007
Location: SE Michigan, USA
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It reads to me like all three requirements are minimums. Is there a problem if more than 200 ng is sent in? Is there value to conserving your DNA sample... -
First, the floor load under the safe is 90 kg x 9.81 N/kg / (0.4 m x 0.45 m) = 4.905 kN/m² ( or kPa), nearly at the limit. Alternatively, the 5 kPa limit...Leave a comment:
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0.08% (generally the legal limit in US) is 0.08 g/dL or 80 mg/dL. Tighter limits apply to pilots, commercial drivers, underage drivers, etc.
...Leave a comment:
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2200 ft² x 1/3 ft x 1 yd³/27 ft³ = 27.2 yd³
However, it is delivered "loose" and will pack down over time. I would allow an extra 20%,...Leave a comment:
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Kilowatt hours of electricity? How is it produced? Some countries publish average figures for their mix of power plants, but it changes over time as...Leave a comment:
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8 ft x 8 ft x 1/12 ft = 5.33 ft3
Dry sand is about 90 lb/ft3 so about 480 lb....Leave a comment:
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We need to determine the total mass in a 15 cm deep core 1 ha in size. A hectare is a square 100 m on an edge
1.5 g/cm3 x 15 cm x (104 cm)2 = 2.25...Leave a comment:
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You need to know the molar mass (numerically equal to molecular weight). Wikipedia gives 177.29 g/mol
177.29 g/mol x 500 nmol = 88 645 ng or 88.6...Leave a comment:
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This is commonly known as the "digester problem." You weigh out a certain amount of a dry powder (grams) and mix it in a certain volume of liquid...Leave a comment:
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That gets into whether you are counting atoms or diatomic molecules, in other words, moles of what? There are two atoms of oxygen in a molecule of O2....Leave a comment:
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I'm not sure what units you are starting from as I don't understand the "at" in µg-at. Can you explain what it stands for?
Never...Last edited by JohnS; 05-29-2017, 02:21 PM.Leave a comment:
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It's exactly right. I missed the fact you were looking for the molar concentration of Na+, and showed how to find the molar concentration of the molecule,...Leave a comment:
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"M" is shorthand for moles per liter, and may be used with prefixes so mM is millimoles per liter.
You have a mass concentration (milligrams...Leave a comment:
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