Explanation:
First, you have to know the definition of density. Density is mass per unit volume, or D = m/V. In this problem, you are given the mass = 37 g and you are given the volume of 21 cm3. So, the density is simply m/V = 37g/21cm3 = 1.76g/cm3. It's that simple.
Hope this helps. Sorry of it is long
Answer: military
African Americans received the best treatment in the military during war. Making up about 3/4 of the military, African American soldiers proved their efficiency and ability to serve the country, thus receiving more respect from society than if they were to work in more "common" jobs, for example in a factory. However, while they received the best treatment in the military during the war, African Americans still faced segregation within the units of the military, an important fact to note.
Answer : The value of 
for the reaction is, -135.2 kJ
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The formation of 
will be,
The intermediate balanced chemical reaction will be,
(1) 
(2) 
(3) 
We are dividing the reaction 1, 2 and 3 and reversing reaction 3 and then adding all the equations, we get :
(1) 
(2) 
(3) 
The expression for enthalpy of formation of will be,
Therefore, the value of for the reaction is, -135.2 kJ
Diethyl ether, since 20 is closer to 34.6 it should start boiling faster than the other which is no where near it
Answer:
this lesson is the third in a three-part series about the nucleus, isotopes, and radioactive decay. The first lesson, Isotopes of Pennies, deals with isotopes and atomic mass. The second lesson, Radioactive Decay: A Sweet Simulation of Half-life, introduces the idea of half-life.
By the end of the 8th grade, students should know that all matter is made up of atoms, which are far too small to see directly through a microscope. They should also understand that the atoms of any element are alike but are different from atoms of other elements. Atoms may stick together in well-defined molecules or they could be packed together in large arrays.
For students, understanding the general architecture of the atom and the roles played by the main constituents of the atom in determining the properties of materials now becomes relevant. Having learned earlier that all the atoms of an element are identical and are different from those of all other elements, students now come up against the idea that, on the contrary, atoms of the same element can differ in important ways. (Benchmarks for Science Literacy, p. 79.)
In this lesson, students will be asked to consider the case of when Frosty the Snowman met his demise (began to melt). The exercise they will go through of working backwards from measurements to age should help them understand how scientists use carbon dating to try to determine the age of fossils and other materials. To be able to do this lesson and understand the idea of half-life, students should understand ratios and the multiplication of fractions, and be somewhat comfortable with probability
Explanation:
