Water has a density of 0.9982 g/mL, so it will sink.
The molarity of a 250. mL H2SO4 solution that was made from a 20.0 mL of a 10.0 M stock solution is 0.8M.
<h3>How to calculate molarity?</h3>
The molarity of a solution can be calculated using the following expression:
CaVa = CbVb
Where;
- Ca = concentration of acid
- Cb = concentration of base
- Va = volume of acid
- Vb = volume of base
In this question;
- Ca = ?
- Va = 250mL
- Cb = 10M
- Vb = 20mL
Ca × 250 = 10 × 20
250Ca = 200
Ca = 200/250
Ca = 0.8M
Therefore, the molarity of a 250. mL H2SO4 solution that was made from a 20.0 mL of a 10.0 M stock solution is 0.8M.
Learn more about molarity at: brainly.com/question/2817451
This sounds very much like a chicken-egg problem.
The first thing that formed must be hydrogen nuclei. The only other alternative is that the atom was created instantly, and the nuclei sprang forth at the same time as the atom, meaning that neither was technically first. The logic is that an atom can’t form without a nucleus, but it theoretically could be created instantly.
In order to find the two statements, we must first define what the enthalpy of formation and the enthalpy of reaction mean.
Enthalpy of formation:
The change in enthalpy when one mole of substance is formed from its constituent elemetns at standard state.
Enthalpy of reaction:
The change in enthalpy when a reaction occurs and the reactants and products are in their standard states.
Now, we check the statements. The true ones are:
The Hrxn for C(s) + O₂(g) → CO₂(g) is the same as Hf for CO₂
This is true because the formation of carbon dioxide requires carbon and oxygen in their standard states.
The Hf for Br₂<span>(l) is 0 kJ/mol by definition.
Because the bromine is present in its standard state, the enthalpy of formation is 0.
</span><span>The Hrxn for the reaction 1.5H</span>₂<span>(g) + 0.5N</span>₂<span>(g) </span>→ <span>NH</span>₃<span>(g) is the same as the Hf for NH</span>₃<span>(g)
The reactants and products are present in their standard state, and the reaction is the same as the one occurring during the formation of ammonia.
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An atomic number is <span>the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table or chart.</span>
