Answer:
0.00688 moles
Explanation:
The molarity ratio looks like this:
Molarity = moles / volume (L)
After you convert mL to L, you can plug the values into the equation and simplify to find moles.
27.5 mL / 1,000 = 0.0275 L
Molarity = moles / volume <----- Molarity ratio
0.250 M = moles / 0.0275 L <----- Insert values
0.00688 = moles <----- Multiply both sides by 0.0275
Answer:
15.438g H2O
Explanation:
First you need to find the reaction equation:
2H2O+2Na=2NaOH + H2
Hydrogen is a diatomic molecule so it will have a subscript of 2 on the right hand side. From there we can balance the reaction.
Then we can use stoichiometry:
34.2g NaOH * (1 mol NaOH/39.908g NaOH) * (2 mol H2O/2 mol NaOH) * (18.015g H2O/1 mol H20) = 15.438g H2O
It is important that when you use stoichiometry that all your units cancel out until you only have the unit you want.
Answer:
The correct answer to the question is
d. the nucleus is decaying
Explanation:
A radioactive isotope are variations of of a chemical element with different molecular mass and an unstable nucleus that emit alpha, beta or gamma radiation. An isotope releasing an alpha particle during nuclear decay, releases two neutrons and two protons which make up the alpha particle. If an beta particle is released, then a negative charge equivalent to an electron is released from the nucleus during disintegration. Both forms of nuclear decay results in the release of Gamma radiation.
ome isotopes release an alpha particle during nuclear disintegration; an alpha particle consists of two protons and two neutrons (equivalent to the nucleus of an atom of helium). Others release a beta particle, which is an electron, or negatively charged nuclear particle. Beta particles originate in the nucleus, presumably by breakdown of a neutron into its proton-electron components. Gamma rays are released during both types of radioactive decay.
