Answer:
16.6 mg
Explanation:
Step 1: Calculate the rate constant (k) for Iodine-131 decay
We know the half-life is t1/2 = 8.04 day. We can calculate the rate constant using the following expression.
k = ln2 / t1/2 = ln2 / 8.04 day = 0.0862 day⁻¹
Step 2: Calculate the mass of iodine after 8.52 days
Iodine-131 decays following first-order kinetics. Given the initial mass (I₀ = 34.7 mg) and the time elapsed (t = 8.52 day), we can calculate the mass of iodine-131 using the following expression.
ln I = ln I₀ - k × t
ln I = ln 34.7 - 0.0862 day⁻¹ × 8.52 day
I = 16.6 mg
Answer:
Chemical reactions are balanced by adding coefficients so that the number of atoms of each element is the same on both sides. Stoichiometry describes the relationship between the amounts of reactants and products in a reaction.
Explanation:
Answer:
A lower ph is always more acidic, due to the increased concentration of hydrogen ions in the solution/substance.
A ph of 3 is 100 times more acidic than a pH of 5, and this is due to the increments on the scale.
Answer:
<u>The incorrect choice is the last one:</u>
- <em>In the Leucipo and Democritus atomic model, electrons had negative charges.</em>
Explanation:
The translation of the question is:
Choose the incorrect statement. *
- Matter is everything that has mass and occupies volume.
- Mass and weight are different quantities. Mass is a measure of how much matter an object has, and weight is a measure of the gravitational pull force suffered by the object.
- Dalton's atomic model has similarities to the atomic model described by Leucipo and Democritus.
- Dalton thought that atoms of the same element could not combine, as they developed mutual repulsion.
- In the Leucipo and Democritus atomic model, electrons had negative charges.
<h2>Solution</h2>
The <em>last statement is false</em> because Leucipo and Democritus thought that the atom was an indivisible particle. This is, they did not think there were subatomic particles, such as electrons. Furthermore, the idea of a particle with a negative charge was developed much time (centuries) later.
As for the other statements:
- <em>Matter is everything that has mass and occupies volume</em>: this is the current definition of matter; for instance, wood, air, atoms, have mass and occupy volume. Thougths, feelings do not have either mass or occupy a volume, they are not matter.
- <em>Mass and weight are different quantities</em>. <em>Mass is a measure of how much matter an object has, and weight is a measure of the gravitational pull force suffered by the object</em>. Indeed, the mass is determined by the number of atoms of the substance, but weight is the force of attraction from Earth (or other planet, if the object is in other planet). Mass does not change with the location; weight does.
- <em>Dalton's atomic model has similarities to the atomic model described by Leucipo and Democritus</em>: sure. This is a hystorical question. Leucippus and Democritus were two Greek phylosophers who believed that the matter was formed by tiny solid particles, the atom.
- <em>Dalton thought that atoms of the same element could not combine, as they developed mutual repulsion</em>. In the times of Dalton, when he developed the law of multiple proportions, atoms of a same kind were thought to repel each other.
Answer:
C) formaldehyde, H2C=O.
Explanation:
Hello,
In this case, given that the hydrogen bondings are known as partial intermolecular interactions between a lone pair on an electron rich donor atom, particularly oxygen, and the antibonding molecular orbital of a bond between hydrogen and a more electronegative atom or group. Thus, among the options, C) formaldehyde, H2C=O, will exhibit hydrogen bonding since the lone pair of electrons of the oxygen at the carbonyl group, are able to interact with hydrogen (in the form of water).
Best regards.
