7. Mr. Wurtz performed a demonstration for his science students in a well-ventilated room. He mixed together two samples of different white powdery substances in an open beaker. The dry mixture soon became wet, and the students could smell ammonia. The temperature of the beaker dropped dramatically, so much so that the liquid that formed in the beaker began to freeze. A liquid formed at the bottom of the beaker. The temperature of the mixture dropped dramatically. Powder 2 Ammonia Odor O Agas with a strong smell was released from the mixture. time The powdery substances dissolved in the water. Icy Solution CLEAR ALL Powder 1 Mr. Wurtz told the class that a chemical reaction had occurred inside the beaker. Which of the following is not evidence that a chemical reaction occurred?A. A liquid at the bottom of the breaker B. The temperature of the mixture drop dramatically. C. A gas with a strong smell was released from the mixture. D. the powdery substances dissolved in the water.

the form of energy changes and the total energy increases0l

many other transport proteins, often called pumps, move materials against a concentration gradient. active transport drives molecules across a membrane from a region of lower concentration to a region of higher concentration. this process, shown in figure 5.1, uses transport proteins powered by chemi- cal energy.

answer-

the statement that f(x) = |x+a| + b has exactly one x-intercept is sometimes correct.

solution-

it solely depends on b, whether the function will have one or two or zero x intercept.

this plot of the given function, f(x) = |x+a| + b will be the basic absolute value graph i.e v shape, with vertex translated to (-a, b), instead of origin.

1-   if b is zero, the graph will have exactly one x-intercept, at x= -a

2- if b is positive, the whole graph will be above the x-axis, hence it will have no x-intercepts.

3- if b is negative, the graph will be below the x-axis, hence it will have two x-intercepts.

∴ the statement is sometimes true.

i don't understand

explanation:

i don't understand your question