Answer:
52 da
Step-by-step explanation:
Whenever a question asks you, "How long to reach a certain concentration?" or something similar, you must use the appropriate integrated rate law expression.
The i<em>ntegrated rate law for a first-order reaction </em>is
ln([A₀]/[A] ) = kt
Data:
[A]₀ = 750 mg
[A] = 68 mg
t_ ½ = 15 da
Step 1. Calculate the value of the rate constant.
t_½ = ln2/k Multiply each side by k
kt_½ = ln2 Divide each side by t_½
k = ln2/t_½
= ln2/15
= 0.0462 da⁻¹
Step 2. Calculate the time
ln(750/68) = 0.0462t
ln11.0 = 0.0462t
2.40 = 0.0462t Divide each side by 0.0462
t = 52 da
Conservation
conservation is the act of protecting animals and resources for current and future generations
Valence électrons don’t define which group You are in so you can cross those choices out.
A would be incorrect because element 1 has 1 valence electron while element 2 has 2 valence electrons.
D would be correct because both elements have two valence electrons.
Also, pls don’t hate if I am wrong!
Answer:
- There will be 1.23 moles of helium in the balloon at STP
Explanation:
1) <u>Initial conditions of the helium gas</u>:
- V = 20.0 liter
- p = 1.50 atm
- T = 25.0 °C = 25.0 + 273.15 K = 298.15 K
2) <u>Ideal gas equation</u>:
- pV = n RT
- p, V, and T are given above
- R is the Universal constant = 0.0821 atm-liter / ( K - mol)
- n is the unknown number of moles
3) <u>Solve for n</u>:
- n = 1.50 atm × 20.0 liter / (0.0821 atm-liter /k -mol ×298.15K)
4) <u>At STP:</u>
- STP stands for standard pressure and temperature.
- The amount (number of moles) of the gas will not change because the change of pressure and temperature, so the number of moles reamain the same: 1.23 mol.
Covalent bonds are strong bonds. Atoms that share pairs of electrons form molecules. A molecule is a group of atoms held together by covalent bonds. A diatomic molecule is a molecule containing only two atoms.
