A 3.82-g sample of magnesium nitride is reacted with 7.73 g of water: Mg3N2 + 3H2O → 2NH3 + 3MgO The yield of MgO is 3.60 g. What is the percent yield in the reaction?

When the following equation is balanced, the coefficients are ________. C 8H 18 + O 2 → CO 2 + H 2O

Butane reacts with oxygen according to the following equation. 2 C4H10(g) + 13 O2(g)  → 8 CO2(g) + 10 H2O(g) If 2.0 moles of butane reacts with 12 moles of oxygen gas and 6.2 moles of CO2 are produced, what is the percent yield of the reaction?

What is the wavelength of light (nm) that has a frequency of 6.44 × 10 13 Hz? 1nm = 10^-9 m

If 100. mL of 0.100 M K2SO4 is added to 200. mL of 0.150 M KCl, what is the concentration of K+ ions in the final solution? Assume that the volumes are additive.

A yellow photon has a frequency of 516 THz. (1 THz = 1012 Hz).  What is the energy (J) of this photon?

Now, find the list of materials that are authorized for this exam. You can find these allowed links and other directions by clicking the “Assessment Details” button.   Write the name of the animal that appears in the list.

Problem-solving portion:Question 2 conituned:  Because elderly people may have difficulty standing straight to have their heights measured, a study looked at predicting overall height from height to the knee. The data, in centimeters (cm), for five elderly men are listed in the table.r = correlation between x and y = 0.877 = mean of the values of x = 49.72 = mean of the values of y = 164.72sx = standard deviation of the values of x = 6.36sy = standard deviation of the values of y = 17.6Use the least‑squares regression equation to predict the height (y) when the knee height is 100 cm.  Does this value make any sense? Please justify.

A survey was designed to study how brook trout populations respond to various levels of urbanization. Urbanization had three levels: low, medium, and high impact. Historical habitats for brook trout were observed, with 200 habitats randomly selected within each level of urbanization, for a total of 600 habitats. Researchers marked each population as extirpated or present. The data are given in the following two-way table.   Extirpated Present Total Low impact 25 175 200 Medium impact 80 120 200 High impact 195 5 200 What percent of habitats subject to high levels of urbanization were found to be present?

Which of the following is a durable protein that makes which skin layer waterproof and resistant to bacteria and viruses?