Answer:
independent variable - the thing you change
dependent variable - the thing you measure
control variables - the things you keep the same
Answer: D. 19.9 g hydrogen remains.
Explanation:
To calculate the moles, we use the equation:
a) moles of 
b) moles of 
According to stoichiometry :
1 mole of require 1 mole of
Thus 0.0787 moles of 
require=
of
Thus is the limiting reagent as it limits the formation of product and acts as the excess reagent. (10.0-0.0787)= 9.92 moles of are left unreacted.
Mass of 
Thus 19.9 g of remains unreacted.
Answer:
a
Explanation:
The formation of ion occurs when an atom that is said to be neutral gains or losses electrons.
At the time it gains electrons, it is regarded that a negative ion (anion) is formed.
When it loses electron, it is regarded that a positive ion (cation) is formed.
Atomic number = No of protons and electrons occurring in a neutral atom.
Given that:
Protons = 14
electron = 18
Net Charge = no of proton - no of electron
= 14 - 18
= -4
Mass number = 14 + 15 = 29
So, the chemical symbol = 
For ion with
27 proton, 32 neutrons and 25 electrons
Net charge = 27 - 25
= +2
Mass number = 27 + 32 = 59
Thus, the chemical symbol = 
<u>Answer:</u> The correct answer is isotopes generally have the same chemical properties, but often different nuclear properties.
<u>Explanation:</u>
Isotopes are defined as the chemical species of the same element which have same atomic number but differ in their mass number.
Atomic number is defined as the number of protons or electrons that are present in a neutral atom.
Atomic number = number of protons = number of electrons
Mass number is defined as the sum of number of protons and neutrons that are present in an atom.
Mass number = Number of protons + Number of neutrons
Nuclear properties of an element is determined by the number of protons and neutrons present in a nucleus.
Chemical properties of an element is determined by the number of electrons present in an atom.
Isotopes have same atomic number, this means that they have same number of protons and electrons but they differ in mass number, which means that they differ in number of neutrons.
Hence, isotopes will have same chemical properties but different nuclear properties.
Answer:
Explanation:
Columns and rows used in the periodic classification of elements shows trends in the properties of elements.
The periodic columns are called groups and they denote vertical arrangement of elements.
The horizontal rows are the periods.
- Groups and Periods provides a very simple way to classify elements.
- They reflect trends among different elements that are found in nature. Following these groups and periods, it is even possible to predict the nature of an undiscovered element.
- Certain parts of the table have some unique elements on them with some distinctive properties that distinguish them from others.
- The atomic number is the basis of this classification. By this, it is possible to delineate that elements with similar properties are located on the same group.
