A $1.00 \cdot 10^{-6} \ g$ sample of nobelium, $_{102}^{254} \mathrm{No}$, has a half-life of 55 seconds after it is formed. What is the percentage of $_{102}^{254} \mathrm{No}$ remaining at the following times?

(a) 5.0 min after it forms

(b) 1.0 h after it forms

the entities in a nuclear reaction that consist of helium atoms are known as?

Which of the following combinations of atoms is most likely to result in a chemical reaction?

a. hydrogen and hydrogen

b. hydrogen and helium

c. helium and helium

d. neon and helium

There is more than one isotope of natural uranium. If a researcher isolates 1.00 mg of the relatively scarce $^{235} \mathrm{U}$ and finds this mass to have an activity of 80.0 Bq, what is its half-life in years?

The given set is a subset of C[−1, 1]. Which of these are also vector spaces? $F=\{f(x)$ in $C[1,1]: f(1)=0\}$

The thermite reaction, Fe$_2$O$_3$(s) + 2 Al(s) $\longrightarrow$ 2 Fe(s) + Al$_2$O$_3$(s), is one of the most exothermic reactions known. The heat released is sufficient to melt the iron product; consequently, the thermite reaction is used to weld metal under the ocean. $\Delta H^{\circ}$ for the thermite reaction is -851.5 kJ/mole. What is the mass change per mole of Fe$_2$O$_3$ that accompanies this reaction?

Express the given vector as a linear combination of the vectors in the given set Q. $f(x)=\cos 2 x$ and $Q=\left\{\sin ^{2} x, \cos ^{2} x\right\}$

It is estimated that weapons tests in the atmosphere have deposited approximately 9 MCi of $^{90} \mathrm{Sr}$ on the surface of the earth. Find the mass of this amount of $^{90} \mathrm{Sr}.$

(a) Find the charge, baryon number, strangeness, charm, and bottomness of the $J / \Psi$ particle from its quark composition. (b) Do the same for the $\Upsilon$ particle.

A parabolic trough collector can be designed using state-space techniques. For simplicity, pure time delay will be ignored here, although it could be handled in several different ways. Consider the open-loop transfer function

$$G(s)=\frac{137.2 \times 10^{-6} K}{s^{2}+0.0224 s+196 \times 10^{-6}}$$

Design a state feedback controller with integral control to yield zero steady-state error, such that the system transient response results in a damping factor of $\zeta$ = 0.5 with a settling time T$_{s}$ = 200 sec. Simulate the step response of your designed system using a computer program.

What is the enthalpy change ($\Delta$H) in kJ for the following reaction?

2Al(s) + Fe$_2$O$_3$(s) $\longrightarrow$ 2Fe(s) + Al$_2$O$_3$(s)

Use the enthalpy changes for the combustion of aluminum and iron:

2Al(s) + $\frac{3}{2}$O$_2$(g) $\longrightarrow$ Al$_2$O$_3$(s) $\,\,\,\,\,\,\,\,\,\,\,\,\Delta$H = -1676.0 kJ

2Fe(s) + $\frac{3}{2}$O$_2$(g) $\longrightarrow$ Fe$_2$O$_3$(s) $\,\,\,\,\,\,\,\,\,\,\,\,\Delta$H = -822.1 kJ

Write the equation of the parabola in standard form, and find the vertex of its graph. y = x$^{2}$ - 8x + 3

Hydrochloric acid and calcium hydroxide react according to the following equation:

2HCl(aq) + Ca(OH)$_2$(aq) $\rightarrow$ CaCl$_2$(aq) + 2H$_2$O(l)

Calculate the standard enthalpy ($\Delta H$) for this reaction from the reactions below:

CaO(s) + 2HCI(aq) $\rightarrow$ CaCl$_2$(aq) + H$_2$O(l) $\hspace{1cm}$ $\Delta H$ = -186.0 kJ

CaO(s) + H$_2$O(l) $\rightarrow$ Ca(OH)$_2$(s) $\hspace{2.2cm}$ $\Delta H$ = -62.3 kJ

Ca(OH)$_2$(s) $\rightarrow$ Ca(OH)$_2$(aq) $\hspace{2.65cm}$ $\Delta H$ = -12.6 kJ

Determine the value of the expression pow(4, 2.0). (For decimal numbers, round your answer to two decimal places.)