Ajuda com o dever de casa de química

Pour préparer une solution d'acide propénoique de volume V=200mL .On fait dissoudre m=1,48g d'acide propanoique C_(2)H_(5)COOH dans l'eau distillée, puis on immerge l'électrode de pH-mètre dans et on trouve que : pH=3,09 concentration initiale d'acide propanoique . la réaction acido-basiqu e de propanoiqu avec d'eau. le tableau d'avancement , en fonction de C,V,x et x_(epsilon q) Exprimer le taux d'avancement final r en fonction de pH et C. la valeur de r . La transformation est-elle totale où limitée? Montre que l'expression du quotient de réaction à l'équilibre associé à cette réaction 'écrit sous la forme suivante : Q_(eq)=(Ccdot r^2)/(1-r) , et calculer sa valeur. onnées : La masse molaire de l'acide propanoique : M(C_(2)H_(5)COOH)=74gcdot mol^-1

. 63. The number of electron shells in a magnesium atom is __ A. 1 C. 3 B. 2 D. 4 64. Valence electrons are electrons located __ C. in the outermost energy level A. in the nucleus of an atom D. throughout the atom B. in the first energy level of an atom 65. In an electron dot structure of an element, the dots are used to represent __ A. all the electrons in an atom C. the complete electron arrangement B. the valence electrons D. only the electrons that will participate in bond formation 66. One element that has 5 valence electrons A. lithium C. nitrogen B. carbon D. sulfur 67. Silicon has __ valence electrons. A. 2 C. 6 B. 4 D. 8 68. An atom with 7 valence electrons A. Mn C. I B. N D. Ag 69. Group 17 element with the highest electronegativity is? A. CI C. F B. I D. Br le following has the largest atomic radius? C. Na D. Mg 71. Does ionization energy increase or decrease from left to right across a period on the periodic table? A. increase B. decrease 72. The third element in Group 14 is Germanium. It has an atomic number of 32 What is the atomic number of the second element in this group? A. 14 C. 31 B. 50 D. 33 73. Find the element in period 3, group 15 What is the atomic mass of this element? A. 15 C. 30.97 B. 33 D. 74.92

ng is a chemical change in the following list? read C. grinding of wheat to make flour s in the sunshine D. using modeling clay to make a toy ng would NOT be a physical change? to make ice cubes C. boiling water for ramen of aluminum foil D. burning gasoline in a lawnmower e formation of fog on a cool humid day, what type of event nge in oxygen C. a physical change in water ge in air D. a chemical change in water nd formed in a mold to make a piece of jewelry,what type nge C. evaporation D. a physical change is a physical change? a fireplace C. iron rusting D. digesting food is an example of a homogeneous mixture? oil C. salt dissolved in water D. gasoline mixed with water s a compound? gauge C. aluminum (Al) in a can aker D. gold (Au) in a ring

Quais são os tipos de materiais que entram no composição dos cateteres menos relacionados às ICS? Escolha uma opção: a. São os compostos por polietileno. b. São os compostos por teflon. C. São os compostos por PVC. d. São os compostos por polivinil clorado. e. Sǎo os compostos por poliuretano.

of the following metals is the least reactive? A. Pb B. Ca C. Cu D. Au 21. Which of the following metals is more reactive based on the reaction: Rb+Fe(NO_(3))_(2)arrow Rxn A. Rb B. Fe C. NO_(3) D. Fe(NO_(3))_(2) 2. Which of the following metals is more reactive based on the reaction: ScSO_(4)+Nbarrow NoRxn A. Nb B. Sc C. SO_(4) D. ScSO_(4) Determine whether the following reaction will occur: Pb(OH)_(2)+Niarrow A. Rxn will occur B. Rxn will not occur etermine whether the following reaction will occur and if it will, p Ag+Sn(NO_(3))_(2)arrow A. Rxn will not occur B. Rxn will occur; AgSn+NO_(3) C. Rxn will occur; Ag(NO_(3))_(2)+Sn D. Rxn will occur; AgNO_(3)+Sn