An atom has 5 protons and 7 neutrons. What is its mass number?
Answers
mass number = 5 + 7
mass number = 12
= 5 + 7
= 12 u.
Thus, the answer is 12 u.
Related Questions
Which statement describes how an atom in the ground state becomes excited?(1) The atom absorbs energy, and one or more electrons move to a higher electron shell.(2) The atom absorbs energy, and one or more electrons move to a lower electron shell.(3) The atom releases energy, and one or more electrons move to a higher electron shell.(4) The atom releases energy, and one or more electrons move to a lower electron shell.
In order to separate two substances by fractional crystallization, the two substances must differ in which of the following?(A) solubility (B) specific gravity (C) vapor pressure (D) viscosity (E) freezing point
A scientist thinks that ducks swim faster when they are in cold water. He tests two groups of ducks, one in cold water and one in room temperature water. He records how fast they swim.Experimental Group:Control Group:
Someone please help with these chemistry questions
Answers
Answers
Answer:
2.53 grams of hydrogen gas will be produced and 12.2 many grams of the excess reactant i.e. calcium will be left over.
Explanation:
Moles of calcium =
Moles of HCl =
According to reaction, 2 moles of HCl reacts with 1 mole of calcium :
Then 2.53 moles of HCl will recat with :
of calcium.
As we can see moles of calcium are in excessive amount. Hence calcium is an excessive reagent.
Moles of calcium left unreacted =1.57 mol - 1.265 mol =0.305 mol
Mass calcium left unreacted = 0.305 mol × 40 g/mol =12.2 g
Since, calcium is an excessive reagent HCl is limiting reagent and the amount of hydrogen gas produced will depend on HCl .
According to reaction, 2 moles of HCl gives 1 mole of hydrogen gas.
Then 2.53 moles of HCl will give:
of hydrogen gas.
Mass of 1.265 mol of hydrogen gas = 1.265 mol × 2 g/mol = 2.53 g
2.53 grams of hydrogen gas will be produced and 12.2 many grams of the excess reactant i.e. calcium will be left over.
Answer:
2.55 g of hydrogen
12.17 g calcium.
to nearest hundredth.
Explanation:
The balanced equation is:
Ca + 2HCl ---> CaCl2 + H2
Using the atomic masses
40.078 g Ca react with 72.916 g of HCl to give 2.016 g HCl
The ratio of Ca to HCl in the above is 1 to 1.81935
so 62.8 g Ca reacts with 62.8 * 1.81935 = 114.245 g HCl
so there is excess of Ca in the given weights.
Therefore the mass of Hydrogen produced
= (2.016 / 72.916) * 92.3
= 2.552 g of hydrogen gas.
The mass of calcium required to produce 2.552 g of hydrogen is:
(2.552 / 2.016) * 40.078
= 50.73 g
So the excess of calcium is 62.8 - 50.73
= 12.17 g.
Answers
The correct option is False.
The first organic compound synthesized in the lab was urea. It was synthesized from silver cyanate and ammonium chloride. It is named Wöhler synthesis after the German chemist.
NH₄Cl + AgNCO → H₂NCONH₂
Urea was first synthesized in 1828 and its synthesis was the beginning of modern organic chemistry.
Hope this helps! :)
Answers
Since height is a basic physical property of length, the height of a classroom ceiling is expressed in meters, or meters, or meters.
What is physical property of length?
There are some physical characteristics of matter, such as length, mass, volume, weight, and so forth, that are dependent on the amount or size of the substance.
As the size or amount of the matter changes, so do these qualities of matter and their values.
A quality of matter that is unrelated to a change in its chemical makeup is called a physical property.
Density, color, hardness, melting and boiling points, and electrical conductivity are a few common examples of physical qualities.
The physical characteristics include color, phase, odor, and boiling point. Reactivity with oxygen is not a physical quality because it depends on the chemical makeup of the thing.
Therefore, meter is used to express the height of your classroom ceiling.
Learn more about length here:
#SPJ2
Hope that helps!
60.2 mg = _____ g
Answers
Answer:
60.2 mg is equal to 0.0602 g.
Explanation:
Given = 60.2 mg
To find : 60.2 mg = ? g
Solution:
We know that in 1 gram there are 1000 milligrams.
1 g = 1000 mg
Then in , 1 mg = 0.001 g
So, 60.2 mg = 60.2 mg 0.001 g=0.0602 g
(2) CH3CH2CH2CH3
(3) CH3CH2CH2COOH
(4) CH3CH2COOCH3
Answers
formula represents a hydrocarbon. Therefore, option (2) is correct.
Hydrocarbons are merely carbon and hydrogen. Aliphatic or aromatic. Aliphatic hydrocarbons are saturated or unsaturated open-chain hydrocarbons.Saturated aliphatic hydrocarbons have single bonds, while unsaturated ones have double or triple bonds.
Aromatic hydrocarbons have alternating double bonds in a ring.Only option 2——is a hydrocarbon. Butane, a saturated aliphatic hydrocarbon, with four carbon and 10 hydrogen atoms.
Learn more about hydrocarbons, here:
#SPJ6