For this question, assume that you have 1 compound. This compound is divided in half once, so you are left with 0.5. That 0.5 that remains is divided in half again, this is the second half-life, and you are left with 0.25. The final half life involves dividing 0.25 in half, which means you are left with 0.125. For the answer to make sense, you need to know your conversions between decimals and fractions. To make it simple, if you have 0.125 and you times it by 8, you are left with your initial value of 1. Therefore, after three half-lives, you are left with 1/8th of the compound.
Answer:
the chemical element of atomic number 2, an inert gas which is the lightest member of the noble gas series.
Explanation:
Because it is very unreactive, helium is used to provide an inert protective atmosphere for making fibre optics and semiconductors, and for arc welding. Helium is also used to detect leaks, such as in car air-conditioning systems, and because it diffuses quickly it is used to inflate car airbags after impact.
You add solute until it can't dissolve anymore.
Answer:
1) Reaction rate, in chemistry, the speed at which a chemical reaction proceeds. It is often expressed in terms of either the concentration (amount per unit volume) of a product that is formed in a unit of time or the concentration of a reactant that is consumed in a unit of time.
2) By collecting the hydrogen gas that is produced over water or in a syringe, rate graphs can be produced. The volume of gas produced and the time taken need to be recorded. The rate of the same reaction could be monitored by measuring the change in the mass of reactants as they react to form products.
Answer:
24.0 g C₃H₈
Explanation:
To find the mass of C₃H₈, you need to (1) convert grams CO/H₂ to moles CO/H₂ (via molar mass), then (2) convert moles CO/H₂ to moles C₃H₈ (via mole-to-mole ratio from reaction coefficients), and then (3) convert moles C₃H₈ to grams C₃H₈ (via molar mass). It is important to arrange the conversions/ratios in a way that allows for the cancellation of units (the desired unit should be in the numerator). The final answer should have 3 sig figs to reflect the sig figs in the given values.
Molar Mass (CO): 12.011 g/mol + 15.998 g/mol
Molar Mass (CO): 28.009 g/mol
Molar Mass (H₂): 2(1.008 g/mol)
Molar Mass (H₂): 2.016 g/mol
Molar Mass (C₃H₈): 3(12.011 g/mol) + 8(1.008 g/mol)
Molar Mass (C₃H₈): 44.097 g/mol
3 CO + 7 H₂ ----> 1 C₃H₈ + 3 H₂O
^ ^ ^
45.8 g CO 1 mole 1 mole C₃H₈ 44.097 g
----------------- x ------------------ x -------------------- x ------------------ =
28.009 g 3 moles CO 1 mole
= 24.0 g C₃H₈
87.3 g H₂ 1 mole 1 mole C₃H₈ 44.097 g
---------------- x --------------- x --------------------- x ----------------- =
2.016 g 7 moles H₂ 1 mole
= 273 g C₃H₈
It was necessary to find the mass of the products from both of the reactants because you did not know which one was the limiting reagent. The limiting reagent is the reactant which is completely used up first. Because CO produced the smaller amount of product, it must be the limiting reagent. Therefore, the actual amount of C₃H₈ produced is 24.0 grams.
