Answer:
Science is the study of the world and how it works through collecting data using the scientific method. Technology is the application of that scientific knowledge to create devices that solve problems and carry out tasks.
Answer:
10.23 grams of sucrose should be added.
Explanation:
1.15 m means molality (moles of solute in 1kg of solvent)
1.15 moles of sucrose are contained in 1 kg of solvent (1000 g)
Let's determine the moles in our mass of solvent.
Firstly we convert the g to kg → 26 g . 1kg/1000g = 0.026 kg
m . mass (kg) = 1.15 mol/kg . 0.026kg → 0.0299 moles.
Finally we convert the moles to mass (mol . molar mass)
0.0299 mol . 342.3 g/mol = 10.23 g
5. 1 hydrogen, 1 Nitrogen, 3 oxygen
Full Question:
Ammonia chemically reacts with oxygen gas to produce nitric oxide and water. What mass of water is produced by the reaction of 7.7g of ammonia?
Be sure your answer has the correct number of significant digits.
Answer:
12.23g ≈ 12g (2 s.f)
Explanation:
Ammonia chemically reacts with oxygen gas to produce nitric oxide and water. The balanced chemical reaction is given as:
4 NH3 + 5 O2 -------> 4 NO + 6 H2O
From the reaction;
4 mole of ammonia reacts to produce 6 moles of water
From the question;
Moles = mass / molar mass
From the question;
moles of ammonia = mass / molar mass = 7.7 / 17 = 0.4529moles
Number of moles of water produced;
4 = 6
0.4529 = x
x = (0.4529 * 6 ) / 4
x = 0.67935moles
Mass of water = moles * molar mass = 0.67935 * 18 = 12.23g ≈ 12g (2 s.f)
Answer 1
The sample will dissolve in more than 1 minute.
Explanation :-
Generally Solubility and rate of solubility of substances increase with the increase in temperature. So lower the temperature less fast will it dissolve in the same amount of water.
Since at 50 C it takes 1 minute to dissolve, at 20 C which is lower temperature it will take more time to dissolve.
Answer 2
Transition metals
Explanation:-
Hardness depends on the extent of metallic bonding for metals. More the number of electrons more the metallic bonding.
Alkali metals with just 1 valence electron have weak metallic bonding. Alkaline earth metals have just 2 valence electrons. Transition elements has more electrons in penultimate shell and valence shell than lanthanides. Transition metals with most metallic bonding are the hardest
