How many moles are contained in 325 gram sample of ammonium dichromate (NH4)2Cr2O7

If 200mL of 0.60 M MgCl2 (aq) is added to 400mL of distilled water, what is the concentration of Mg2+(aq) in the resulting solut

lara [203]

Answer:

A.0.20M

Explanation:

c 1 V 1 = c 2 V 2

Initial Volume, V1 = 200 mL

Final Volume, V2 = 200 + 400 = 600 mL

Initial Concentration, c1 = 0.60 M

Final Concentration, c2= ?

Solving for c2;

c2 = c1v1 / v2

c2 = 0.60 * 200 / 600

c2 = 0.20M

3 0

1 year ago

II. Pure magnesium metal is often found as ribbons and can easily burn in the presence of oxygen. When 3.86 g of magnesium ribbo

Leto [7]

Answer:

$Excess=3.53g$

Explanation:

Hello,

In this case, the undergoing chemical reaction is:

$2Mg(s)+O_2(g) \rightarrow 2MgO(s)$

Next, we identify the limiting reactant by computing the moles of magnesium oxide yielded by 3.86 g of magnesium and 155 mL of oxygen at the given conditions via their 2:1:2 mole ratios and the ideal gas equation:

$n_{MnO}^{by \ Mg}=3.86gMg*\frac{1molMg}{24.3gMg}*\frac{2molMgO}{2molMg} =0.159molMgO\\\\n_{MnO}^{by \ O_2}=\frac{1atm*0.155L}{0.082\frac{atm*L}{molO_2*K}*275K} *\frac{2mol MgO}{1molO_2} =0.0137molMgO$

It means that the limiting reactant is the oxygen as it yields the smallest amount of magnesium oxide. Next, we compute the mass of magnesium consumed the oxygen only:

$m_{Mg}^{consumed}=0.0137molMgO*\frac{2molMg}{2molMgO} *\frac{24.3gMg}{1molMg} =0.334gMg$

Thus, the mass in excess is:

$Excess=3.86g-0.334g\\\\Excess=3.53g$

Regards!

5 0

1 year ago

In general, the presence of atoms of what element(s) makes a molecule polar

NISA [10]

Polarity of a molecule doesn't depend only on the presence of certain atom(s). It also depends on symmetry. For example, take the alkanes family $C_{n}H_{2n+2}$ . These molecules are generally nonpolar, because there is no net dipole moment. Now, dipole moment arises due to <span>difference in the electronegativity of carbon and the other element. In organic chemistry, generally these atoms are Oxygen, Halogens, Nitrogen. Because of their high electronegativity, they cause a net dipole moment resulting in polarity.

</span> $H_3C-CH_3$ is symmetrical and hence non-polar.

$H_3C-O-CH_3$ is asymmetrical and polar. It's structure is bent because of oxygen lone pairs.

3 0

2 years ago

After recrystallization, the final weight of biphenyl is found to be 0.02 g. Assume that all steps were carried out correctly, n

Lubov Fominskaja [6]

Explanation:

From the source, The student recrystallized biphenyl by using benzene. Biphenyl is non polar and so is benzene. Biphenyl is very soluble in benzene at low as well as high temperature. Thus, it do not recrystallize as like dissolves like and gives a very poor yield.

The good recovery of the product is dependent on compound having high solubility at the high temperatures and having low solubility at the low temperatures.

6 0

2 years ago

Drag the labels onto the flowchart to indicate how food molecules reach the body’s cells and fuel cellular respiration. start wi

kogti [31]

Start with the ingestion of food on the left. Eating food provides fuel & building blocks for your body, after food is broke down in the digestive system, it is transported to cells via the circulatory system, fuel molecules are broken down further in glycolysis& the citric acid cycle, ATP is produced with <span>the help of the electron transport chain.</span>

3 0

1 year ago