10/28/20
Which would emit the lowest frequency?
Which energy transition would emit a photon with the lowest frequency of light in a hydrogen-like atom? n=2 to n=3n=3 to n=9n=8 to n=5n=4 to n=2
10/28/20
Messages to Tutors Not Showing Up in Inbox
I'm messaging various tutors, but they aren't showing up in my inbox. Are the messages going through? Please help!!
09/23/20
. Complete the following table.
isotope, atomic number, mass number, number of protons, number of neutrons
236/92 U
94/43 Tc
09/23/20
Calculate the half-life of the radioisotope
4. A 160. mg sample of radium-224 weighs 20.0 mg after 9.0 years. Calculate the half-life of the radioisotope.
01/29/20
Biology Question
How many grams of NaCl would you dissolve in water to make a 500 mM NaCl solution with 1-liter final volume ?
01/29/20
Biology Question
How much milliliters of absolute ethanol (100% ethanol) would you mix with how much milliliter of pure water to make 100ml of 70% (v/v) ethanol solution ?
01/24/20
Can you explain the evidence for why mass is conserved during a chemical reaction using the balanced chemical equation below.
Na2SO3 + 2 HCL = 2NaCl + H2O + SO2
01/19/20
What is a mass spectrum?
01/10/20
You produce 0.36 g hydrogen gas using 15 g copper(II). What is your percent yield?
Cu+H2SO4–>? partial answer: 7X.XX%
01/09/20
How are the molecules in a hot cup of water different from the molecules in a cold cup of water?
01/08/20
What will happen if the concentrations of Ca and HCl are increased?
The equation below shows the reaction of calcium (Ca) with hydrochloric acid (HCl). Ca (s) + 2 HCl (aq) → CaCl2 (aq) + H2 (g)
12/11/19
Why is the Heat of Vaporization for both Na and NaCl is higher than the Heat of Fusion? Why does Sodium has higher Hvap, whereas sodium chloride has the higher heat of fusion?
Hfus(kJ/kg) Hvap(kJ/kg)Na 113 4236NaCl 517 3517
Volume Occupying STP
What volume does 1.5 x 1024 molecules of CO2 occupy at STP?
12/09/19
How do you criss cross a compound with four elements in it?
For example, folic acid and Thiamine mononitrate
12/09/19
What is the subshell corresponding to the following sets of quantum numbers? An example of how to write your answer is 2s.
n= 2, l=1
n=2, l=0
12/08/19
Chemistry question
1a. Consider the following reaction:2HBr(aq)+Sr(OH)2(aq) → 2H2O(l)+SrBr2(aq)Enter the complete ionic equation for this reaction.Express your answer as a complete ionic equation. Identify all of the...
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12/03/19
Calculate the solubility
Calculate the solubility (in mol/L) of Co(OH)3 (Ksp = 3 ✕ 10−43) in each of the following. (Assume that all solutions are at 25°C. Enter unrounded values.) (a) water (assume pH is 7.0 and constant)...
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12/01/19
How many grams of calcium hydroxide are needed to neutralize 25 ml of 0.100 m hno3?
Please help very urgent
12/01/19
What is the molecular geometry shape and hybridization central atom for PF5, ClF3, CO2-3, SF-5, I-3?
How to find the molecular geometry shape and what are they to see if I got it correct as well as the hybridization of the central atom. Clear answer to all of them and what are the answers. I need...
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