How many atoms are present in a sample of Calcium (Ca) weighing 127.38g?
Answers
Answer:
1.9139 × 10²⁴ atoms Ca
General Formulas and Concepts:
Chemistry - Atomic Structure
- Reading a Periodic Table
- Using Dimensional Analysis
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
Explanation:
Step 1: Define
127.38 g Ca
Step 2: Identify Conversions
Avogadro's Number
Molar Mass of Ca - 40.08 g/mol
Step 3: Convert
= 1.91388 × 10²⁴ atoms Ca
Step 4: Check
We are given 5 sig figs. Follow sig fig rules and round.
1.91388 × 10²⁴ atoms Ca ≈ 1.9139 × 10²⁴ atoms Ca
Related Questions
An atom of any element must contain(1) an equal number of protons and neutrons(2) an equal number of protons and electrons(3) more electrons than neutrons(4) more electrons than protons
Which characteristics of metal atoms help explain why valence electrons in a metal are delocalized?
Over 99% of the mass of an atom is located
According to the Arrhenius theory a substance that yields hydrogen ions as the only ion in an aqueous solution is
Answers
Answer: Option (a) is correct.
Explanation:
When an object moves from its initial position, it acquires some energy. This energy is called kinetic energy, as it is governed by the motion of an object.
The formula to calculate kinetic energy is as follows.
kinetic energy =
where,
m = mass of object
v = velocity of object
Thus, it is concluded that kinetic energy is the energy an object has due to its motion.
Niels Bohr
Ernest Rutherford
John Dlaton
Answers
Neil Bohr is the scientist who invented a model of the atom that most closely resembles the modern electron cloud model.
What is an atom?
An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
Learn more about atom,here:
#SPJ2
Answers
Given:
25.0mL NaOH17.4 mL of a 0.132M HCL
Required:
molarity of NaOH
Solution:
M1V1 = M2V2
(25.0mL) M1 = (0.132 M HCl)( 17.4 mL)
M1 = 0.092 M NaOH
V1 = 0.5 liters
Answers
We have 2.40 moles of NaCl.
We need the molar mass of NaCl. We can calculate this by referencing the periodic table and looking up the atomic weight.
Na = 22.99g
Cl = 35.45g
----------------
+ 58.44g
2.40 moles x (58.44grams) / (1 mole) = 140.26 grams of NaCl
There are 140.26 grams in 2.40 moles of NaCl.
(2) CH2O (4) C12H24O12
Answers
B. 15 protons, 15 electrons
C. 60 protons, 30 electrons
D. 30 protons, 0 electrons