Answer:
Both the initial and final substances are composed of atoms because all matter is composed of atoms. According to the law of conservation of matter, matter is neither created nor destroyed, so we must have the same number and type of atoms after the chemical change as were present before the chemical change.
Explanation:
The atoms that make up your body were produced inside a star and have ... I read once that atoms get recycled so much through the planet that each of ... from William Shakespeare, but I do know this: All of us come from stars. ... If you have gold fillings in your teeth, those atoms came from a star explosion.
Answer:
Molarity is a unit that measures how much moles of solute dissolved in a liter of solvent. Molarity expressed using capital M while molarity, a different unit, expressed using lower case m.
We want to make 0.005 M solution which means we need 0.005 moles of KmnO4 per liter of water. First, we have to calculate how many grams of KMnO4 we need for the solution.
We want to make 250ml solution, so the number of moles of KMnO4 we need will be: 0.005 mol/liter *(250 ml * 1liter/1000ml)= 0.005 mol/liter * 1/4 liter = 0.00125 moles
The molecular mass of KMnO4 is 158g/mol, so the mass of KMnO4 we need will be: 0.00125 moles * 158g/mol= 0.1975 grams
We know that we need 0.1975 g of KMnO4, now we weigh them and put it inside a dish. After that, we prepare Erlenmeyer or a volumetric flask filled with water half of the volume needed(125ml). Pour the weighted solute into the flask, stir until all solute dissolved.
Then we add water to the container slowly until its volume reaches the 250ml mark.
1 half-life - 4.5 days
x half-lives - 27 days
x=(1*27)/4.5=6
6 <span>half-lives have elapsed after 27 days.</span>
Answer:
nitrogen compounds in the air
Explanation:
Answer:
n = 0.271 moles
Explanation:
Given that,
Volume of container, V = 14 L
Pressure of Nitrogen gas, P = 375 torr
Temperature. T = 37°C=37+273=310°C
We need to find the number of moles of nitrogen in the container. Using gas equation,
PV = nRT
R is gas constant, R = 0.082 L-atm/mol-K
Since, 1 atm=760 torr
375 torr = 0.493 atm
Now,
So, there are 0.271 moles of Nitrogen in the container.
