Answer:
1.63ₓ10⁻⁶ g of U
139.03 g of H
0.385 g of O
141.8 g of Pb
Explanation:
In first place, we need to convert the number of atoms to moles, as we know that 1 mol of anything occupies 6.02×10²³ particles
Therefore:
4.12×10¹⁵ atoms of U . 1 mol / 6.02×10²³ atoms = 6.84×10⁻⁹ moles of U
8.37×10²⁵ atoms of H . 1 mol /6.02×10²³ atoms = 139.03 moles of H
1.45×10²² atoms of O . 1 mol /6.02×10²³ atoms = 0.0241 moles of O
4.12×10²³ atoms of Pb . 1 mol /6.02×10²³ atoms = 0.684 moles of Pb
Moles . Molar mass = Mass (g)
6.84×10⁻⁹ moles of U . 238.03 g/mol = 1.63ₓ10⁻⁶ g of U
139.03 moles of H . 1 g/mol = 139.03 g of H
0.0241 moles of O . 16 g/mol = 0.385 g of O
0.684 moles of Pb . 207.2 g/mol = 141.8 g of Pb
1)The branch of science concerned with the substances of which matter is composed and it is a study of matter.
2)It helps you understand the world around you,chemistry helps you to understand product labels and etc.
3)You find chemistry in daily life in the foods you eat,the air you breathe,cleaning chemicals and etc.
4) Physical,Analytical, Biochemistry,Organic and inorganic chemistry.
Answer:
The correct answer is B) it helps to ensure the result are consistent and repeatable.
Explanation:
Scientist generally repeat an experiment if he or she did not make a mistake in the first one to compare the results of two experiment, if there is no difference in the result or values obtainted from the observation of two experiment. he or she become sure that experiment was done in a right way because if there is some error made when experiment was carried out then the result of two same experiment would be different.
If 10 g of NaOH is diluted to 500 ml with water then the concentration expressed in percent is 0.5 mol/L .
Calculation ,
Given mass in gram = 10 g
Number of moles = given mass /molar mass = 10 g / 40 g/mol = 0.25mole
Given volume in ml = 500 ml
Given volume in liter = 0.5 L
Putting the value of mass and volume in equation i we get concentration expressed in percent .
C = number of moles ×100/ volume in liter = 0.25mole ×100/ 0.5 L
C = 0.5 mol/L
Concentration of solution in terms of percentage can be expressed in two ways
1) percentage by mass
2) percentage by volume
Hence, for liquid solutions, concentration is expressed in terms of percentage by volume.
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The answer is (3) methods to achieve racial equality.
Both Du Bois and Washington had different views on how to promote equality, Du Bois emphasized education and immediate political equality while Washington was more concerned with economic equality in industrial and agriculture
