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Questions in chemistry

[Answered] How many atoms are present in 7.0 moles of Ca?

[Answered] A graduated cylinder is filled to 10.1 cm3 with water and a piece of silicon dioxide is placed in the cylinder, displacing the level to 24.6 cm3. What is the volume of the silicon dioxide piece in cubic centimeters?

[Answered] The following reaction: [tex]$A \rightarrow B+C+\text { heat }$[/tex] is a(n) __________ reaction. A. endergonic B. dehydration synthesis C. exergonic D. anabolic E. exchange

[Answered] How many atoms are present in 7.0 moles of Ca?

[Answered] Using the combined gas law below, identify the variables that would be in the numerator $(A)$ and denominator $(B)$ if you were to rearrange the gas law to solve for final temperature. [tex]\frac{P_1 V_1}{T_1}=\frac{P_2 V_2}{T_2}[/tex] [tex]T_2=\frac{A}{B}[/tex] Numerator $(A)$: P_2 V_2 T_1 Denominator $(B)$: P_1 V_1

[Answered] Which of these reactions requires a net input of energy from its surroundings? exergonic catabolic ATP $\rightarrow$ ADP $+P$ hydrolysis endergonic

[Answered] Consider the intermediate equations: [tex] \begin{array}{ll} C(s)+O_2(g) \rightarrow CO_2(g) & \Delta H_1=-393.5 kJ \\ 2 CO(g)+O_2(g) \rightarrow 2 CO_2(g) & \Delta H_2=-5660 kJ \\ 2 H_2 O(g) \rightarrow 2 H_2(g)+O_2(g) & \Delta H_3=483.6 kJ \end{array} [/tex] With the overall reaction: [tex]C(s)+H_2 O(9) \rightarrow CO(9)+H_2(9) \quad \Delta H_{ran}=?[/tex] What must be done to calculate the enthalpy of reaction? Check all that apply. * The first equation must be halved. * The first equation must be reversed. * The second equation must be halved. * The second equation must be reversed. * The third equation must be halved. * The third equation must be reversed. What is the overall enthalpy of reaction? [tex]\Delta H_{\text {rxn }}[/tex] = kJ

[Answered] A block of aluminum occupies a volume of 15.0 mL and has a mass of 40.5 g. What is its density? density = [?] g / mL

[Answered] Calculate (to 1 d.p.) the percentage mass in water, [tex]H_2O[/tex], of Oxygen

[Answered] If a 0.55 g piece of copper $( Cp =0.387 J / gC )$ at 100 C is placed in 50 g of water $( Cp =4.18$ $J / gC$ ) initially at 23 C , what would the final temperature of the mixture be?