BIOLS 102 Basic Chemistry Chapter 2-3 PDF

BIOLS 102 2 Basic Chemistry Zahra Aman 36122821 BO ABBAS 36663055 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Matt...

BIOLS 102 2 Basic Chemistry Zahra Aman 36122821 BO ABBAS 36663055 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Matter, Element and Atoms ‫ اﻟﻌﻨﺎﺻﺮ واﻟﺬرة‬،‫اﻟﻤﺎدة‬ Periodic table ‫اﻟﺠﺪول اﻟﺪور ي‬ Isotopes ‫اﻟﻨﻈﺎﺋﺮ‬ Electrons and energy ‫اﻹﻟﻜﺘﺮ وﻧﺎت واﻟﻄﺎﻗﺔ‬ Distribution of electrons ‫ﺗﻮز ﻳﻊ اﻹﻟﻜﺘﺮ وﻧﺎت‬ 6 Molecules and compounds ‫اﻟﺠﺰ يء واﻟﻤﺮﻛﺐ‬ 7 Chemical bonding ‫اﻟﺮ واﺑﻂ اﻟﻜﻴﻤﻴﺎﺋﻴﺔ‬ 8 Properties of water ‫ﺧﺼﺎﺋﺺ اﻟﻤﺎء‬ 9 Acids and Bases ‫اﻷﺣﻤﺎض واﻟﻘﻮاﻋﺪ‬ 1 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Matter, Element and Atoms ‫ اﻟﻌﻨﺎﺻﺮ واﻟﺬرة‬،‫اﻟﻤﺎدة‬ Anything that has mass and occupies space ‫ﻛﻞ ﺷﻲء ﻟﻪ ﻛﺘﻠﺔ وﻳﺸﻐﻞ ﺣﻴًﺰ ا‬ Exists in 4 states 1. Solid Matter 2. Liquid ‫اﻟﻤﺎدة‬ 3. Gas 4. Plasma All matter (both living and non-living) is composed of basic substances called elements is a substance that cannot be broken down into substances with different properties (i.e., density, solubility, etc.); composed of one type of atom ‫ وﻻ ﻳﻤﻜﻦ أن ﺗﻨﻘﺴﻢ إﻟﻰ أي ﺷﻲء أﺑﺴﻂ‬،‫ﻣﺎدة ﺗﺘﻜﻮن ﻣﻦ ﻧﻮع واﺣﺪ ﻣﻦ اﻟﺬر ات‬.‫ﻣﻨﻬﺎ ﻣﻦ ﺧﻼل ﺗﻔﺎﻋﻞ ﻛﻴﻤﻴﺎﺋﻲ‬ Element 92 elements are naturally occurring ‫اﻟﻌﻨﺎﺻﺮ‬ 6 out of 92 elements make up 95% of the body weight of organisms Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur CHNOPS Smallest part of an element that displays the properties of the element ‫أﺻﻐﺮ ﺟﺰء ﻣﻦ اﻟﻤﺎدة‬ An element and its atom share the same name Composed of 3 types of subatomic particles Protons +ve charge, 1 amu Atoms ‫اﻟﺒﺮ وﺗﻮﻧﺎت‬ Central ‫اﻟﺬرة‬ nucleus ‫اﻟﻨﻮاة‬ Neutrons No charge, 1 amu ‫اﻟﻨﻴﻮﺗﺮ وﻧﺎت‬ Orbiting clouds -ve charge, very low Electrons mass (negligible in ‫اﻟﺴﺤﺎﺑﺔ‬ ‫اﻻﻟﻜﺘﺮ وﻧﺎت‬ ‫اﻟﻤﺤﻴﻄﺔ‬ calculations) ‫ﺑﺎﻟﻨﻮاة‬ 2 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Atomic Number ‫ = اﻟﻌﺪد اﻟﺬر ي‬number of protons Mass Number ‫ = اﻟﻌﺪد اﻟﻜﺘﻠﻲ‬protons + neutrons Atomic mass approximately equal to the mas number 3 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Practice questions Matter, Element and Atoms 1. The smallest unit of matter that can enter into chemical reactions and is non-divisible by chemical means is called a(an)____. a) Atom b) Molecule c) Nucleus d) Proton 2. The nucleus of an atom contains ____. a) protons b) electrons c) electrons and neutrons d) neutrons and protons 3. The oxygen atom has an atomic number of 8 and an atomic weight of 18. Therefore, an oxygen atom has ____neutrons. a) 8 b) 10 c) 12 d) 18 4. What are the four states of matter? a) Color, shape, size and density b) Solid, liquid, vacuum and plasma c) Heat, temperature, length and mass d) Solid, liquid, gas and plasma 5. Which of the following statement is always correct? a) An atom has equal number of protons and neutrons b) An atom has equal number of electrons and protons c) An atom has equal number of electrons, protons and neutrons d) An atom has equal number of electrons and neutrons 4 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Periodic table ‫اﻟﺠﺪول اﻟﺪور ي‬ Groups Arranged in vertical columns All atoms in a particular group have the same number of valence electrons Atoms within the same group share the same chemical character - Group VIII are noble gasses and are inert Periods Arranged in rows Elements are arranged horizontally by increasing atomic number. Each period shows the number of electron shells for an element. Atoms shown in the periodic table are electrically neutral 5 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Isotopes ‫اﻟﻨﻈﺎﺋﺮ‬ Same element BUT different number of neutrons ‫ ﺗﺨﺘﻠﻒ ﻓﻲ ﻋﺪد اﻟﻨﻴﻮﺗﺮ وﻧﺎت‬،‫ذر ات ﻟﻨﻔﺲ اﻟﻌﻨﺼﺮ‬ Same chemical properties BUT different atomic masses To get the number of neutrons mass number – atomic number = number of neutrons Example: (A) Mass number 12 – atomic number 6 = number of neutrons 6 (B) 13 – 6 = 7 Practice questions Isotopes 6. A carbon atom has six protons but has 7 neutrons, this carbon atom would be called a(n)____. a) Acid b) Compound c) Isotope d) Cation 7. A research article indicates that researchers have used an isotope 𝟑𝑯 to trace a certain metabolic process. From the symbol that is given, we know this is a hydrogen isotope with____. a) three electrons b) three protons c) one proton and two neutrons d) two protons and one neutron 6 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Electrons and energy ‫اﻹﻟﻜﺘﺮ وﻧﺎت واﻟﻄﺎﻗﺔ‬ Electrons determine chemical behavior of atoms Electrons are attracted positively charged nucleus ‫ﺗﻨﺠﺬب اﻻﻟﻜﺘﺮ وﻧﺎت ذات اﻟﺸﺤﻨﺔ اﻟﺴﻠﺒﻴﺔ اﻟﻰ اﻟﻨﻮاة ذات اﻟﺸﺤﻨﺔ اﻹﻳﺠﺎﺑﻴﺔ‬ It takes energy to hold electrons in place, the more distant the shell → the more energy it takes to hold in place ‫ ﻛﻠﻤﺎ ز ادت اﻟﻄﺎﻗﺔ اﻟﻼزﻣﺔ ﻟﺘﺜﺒﻴﺖ اﻻﻟﻜﺘﺮ وﻧﺎت ﻓﻲ‬،‫ﻳﺘﻄﻠﺐ اﻷﻣﺮ ﻃﺎﻗﺔ ﻟﺘﺜﺒﻴﺖ اﻻﻟﻜﺘﺮ وﻧﺎت ﻓﻲ ﻣﻜﺎﻧﻬﺎ وﻛﻠﻤﺎ ﻛﺎن اﻟﻤﺪار اﺑﻌﺪ‬ ‫ﻣﻜﺎﻧﻬﺎ‬ So it takes energy to 1. To push them away from the nucleus 2. To keep them in place Electrons have energy due to their relative position = potential energy ‫اﻟﻄﺎﻗﺔ اﻟﻜﺎﻣﻨﺔ = ﻫﻲ اﻟﻄﺎﻗﺔ اﻟﻤﻮﺟﻮدة ﻓﻲ اﻟﺠﺴﻢ ﻧﺘﻴﺠﺔ وﺿﻌﻴﺘﻪ‬ 7 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Distribution of electrons ‫ﺗﻮز ﻳﻊ اﻹﻟﻜﺘﺮ وﻧﺎت‬ Energy shells where electrons revolve around the nucleus For atoms with atomic number of 20 or less, the following rules apply 1. 1st energy shell can hold to 2 e 2. Each additional shell can hold up to 8 e Valence shell the outermost energy shell of any atom It is important because it determines many of an atom’s chemical properties Octet rule the outermost shell is most stable when it has 8 e Exception, if an atom has only one shell, the outermost valence shell is complete when it has 2 e The number of electrons in the atom’s valence shell determines whether the atom gives up, accepts or shares electrons Bohr Models of Atoms 8 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Practice questions Distribution of Electrons 8. what determines the chemical properties of an atom? a) The number of electrons in the first shell b) The number of electrons in the nucleus c) The number of protons in the nucleus d) The number of electrons in the outer shell 9. Which of the following correctly represents the electronic distribution in the magnesium (Mg) atom? a) 1,8,3 b) 3,8,1 c) 8,2,2 d) 2,8,2 10. If an element contains 11 electrons how many electrons will be placed in the 2nd valence shell? a) 8 b) 9 c) 5 d) 2 11. Chlorine has an atomic number of 17. How many electrons are in the outermost shell? a) 1 b) 7 c) 8 d) 10 9 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 6 Molecules and compounds Molecule ‫اﻟﺠﺰ يء‬ ‫اﻟﺠﺰ يء واﻟﻤﺮﻛﺐ‬.‫ وﻳﺘﻜﻮن ﻣﻦ ارﺗﺒﺎط ذرﺗﻴﻦ أو أﻛﺜﺮ‬.‫ ﻳﺤﻤﻞ ﺻﻔﺎﺗﻪ‬،‫أﺻﻐﺮ ﺟﺰء ﻓﻲ اﻟﻤﺮﻛﺐ‬ 2 or more atoms react or bond together The smallest part of a compound that retains its chemical properties Compound ‫اﻟﻤﺮﻛﺐ‬ ‫ وﻳﻤﻜﻦ ﺗﺤﻠﻴﻠﻪ إﻟﻰ ﻣﻮاد أﺑﺴﻂ‬،‫ﻣﺰ ﻳﺞ ﻣﻜﻮن ﻣﻦ ﻋﻨﺼﺮ ﻳﻦ أو أﻛﺜﺮ ﻣﺘﺤﺪﻳﻦ ﻛﻴﻤﺎﺋًﻴﺎ‬ A molecule containing at least 2 different elements bonded together Formula Tells the number of each kind of atom in a molecule 10 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 7 Chemical bonding ‫اﻟﺮ واﺑﻂ اﻟﻜﻴﻤﻴﺎﺋﻴﺔ‬ Bonds that connect atoms contain energy ‫اﻟﺮ واﺑﻂ اﻟﺘﻲ ﺗﺮ ﺑﻂ اﻟﺬر ات ﺗﺤﺘﻮي ﻋﻠﻰ ﻃﺎﻗﺔ‬ Bonds are formed due to interactions between electrons in the outermost energy shell ‫ﺗﺘﺸﻜﻞ اﻟﺮ واﺑﻂ ﻧﺘﻴﺠﺔ ﻟﻠﺘﻔﺎﻋﻼت ﺑﻴﻦ اﻻﻟﻜﺘﺮ وﻧﺎت ﻓﻲ ﻏﻼف اﻟﻄﺎﻗﺔ اﻟﺨﺎرﺟﻲ‬ The process of bond formation is called chemical reaction ‫ﻋﻤﻠﻴﺔ ﺗﻜﻮﻳﻦ اﻟﺮ اﺑﻄﺔ ﺗﺴﻤﻰ ﺑﺎﻟﺘﻔﺎﻋﻞ اﻟﻜﻴﻤﻴﺎﺋﻲ‬ Ionic bonds ‫اﻟﺮ اﺑﻄﺔ اﻷﻳﻮﻧﻴﺔ‬ Ion An atom that has lost or gained an electron ‫أ ﻳﻮ ن‬ ‫اﻟﺬرة اﻟﺘﻲ ﻓﻘﺪت أو اﻛﺘﺴﺒﺖ إﻟﻜﺘﺮ وًﻧﺎ‬ Forms when electrons are transferred from one atom to another atom and the oppositely charged ions are attracted to each other ‫ﺗﺘﺸﻜﻞ ﻋﻨﺪﻣﺎ ﻳﺘﻢ ﻧﻘﻞ اﻹﻟﻜﺘﺮ وﻧﺎت ﻣﻦ ذرة إﻟﻰ ذرة أﺧﺮ ى وﺗﻨﺠﺬب اﻷﻳﻮﻧﺎت اﻟﻤﺸﺤﻮﻧﺔ ﺑﺸﻜﻞ‬ ‫ﻣﻌﺎﻛﺲ إﻟﻰ ﺑﻌﻀﻬﺎ اﻟﺒﻌﺾ‬ Ionic bond 11 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Salt Solid substances that usually separate and exist as individual ions in water Covalent bonds ‫اﻟﺮ اﺑﻄﺔ اﻟﺘﺴﺎﻫﻤﻴﺔ‬ Results when 2 atoms share electrons so each atom has an octet of electrons in the outer shell ‫ﺗﺘﻜﻮن ﻋﻨﺪﻣﺎ ﺗﺘﺸﺎرك ذرﺗﺎن اﻹﻟﻜﺘﺮ وﻧﺎت ﺑﺤﻴﺚ ﺗﺤﺘﻮي ﻛﻞ ذرة ﻋﻠﻰ ﺛﻤﺎﻧﻲ إﻟﻜﺘﺮ وﻧﺎت ﻓﻲ اﻟﻐﻼف اﻟﺨﺎرﺟﻲ‬ Non polar covalent bonds Sharing electrons equally in the bond ‫ر واﺑﻂ ﺗﺴﺎﻫﻤﻴﺔ ﻏﻴﺮ ﻗﻄﺒﻴﺔ‬ Polar covalent bonds Sharing electrons unequally in the bond ‫ر واﺑﻂ ﺗﺴﺎﻫﻤﻴﺔ ﻗﻄﺒﻴﺔ‬ Electronegativity The ability of an atom to attract electrons towards itself in a chemical bond ‫اﻟﻜﻬﺮ و ﺳﺎﻟﺒﻴﺔ‬ ‫ﻣﺪى ﻗﺎﺑﻠﻴﺔ ذر ات اﻟﻌﻨﺼﺮ ﻋﻠﻰ ﺟﺬب اﻹﻟﻜﺘﺮ وﻧﺎت ﻓﻲ اﻟﺮ اﺑﻄﺔ اﻟﻜﻴﻤﻴﺎﺋﻴﺔ‬ 12 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Practice questions Chemical Bonding 12. If an atom either gains or loses an 17. Which statement is NOT true about electron, the atom is called (an)____. covalent bonds? a) Ion a) A pair of electrons is shared between two b) Element atoms for each covalent bond c) Molecule b) A single covalent bond is drawn as a line d) Isotope between two atoms c) A covalent molecule contains one or more 13. Sodium has 11 electrons arranged in covalent bonds three energy levels. In order to become d) Covalent bonds form when an electron is stable, sodium forms an ion with____. completely lost or gained from an atom a) No charge b) -1 charge c) +1 charge 18. The electrons are unequally shared in d) +8 charge _______, and transferred in __________. a) 𝑶𝟐 , 𝑪𝑯𝟒 14. The ion of an element has 3 positive b) 𝑵𝒂+𝑪𝒍−, 𝑯𝟐𝑶 charges. Mass number of the atom is 27 and c) 𝑪𝑯𝟒 , 𝑵𝟐 the number of neutrons is 14. What is the d) 𝑯𝟐𝑶 ,𝑵𝒂+𝑪𝒍− number of electrons in the ion? a) 13 b) 10 19. An individual water molecule is held c) 14 together by____. d) 16 a) Ionic bonds b) Hydrogen bonds 15.If an atom gains an electron, it forms c) Covalent bonds a____. d) Peptide bonds a) positively charged ion b) covalent bond c) double bond d) negatively charged ion 16. Which type of covalent bond is the strongest? a) Double b) Single c) Quadruple d) Triple 13 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 8 Properties of water ‫ﺧﺼﺎﺋﺺ اﻟﻤﺎء‬ 14 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 15  1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Temperature and water Ice is less dense than water 16 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Practice questions Properties of Water 20. Density of water becomes maximum at ____. a) 10 °C b) 4°C c) 0°C d) -10°C 21. Water falling from clouds forms a rain drop because of what? a) Covalent bonding b) Cohesion c) High heat of vaporization d) Adhesion 22. Water molecules from hydrogen bonds by____. a) The attraction between the positive poles of one water molecule with the negative poles of another b) The sharing of electrons between one water molecule and another c) The transfer of electrons between one water molecule and another d) Water molecules never form hydrogen bonds 23. Which of the following is NOT a property of water? a) It can dissolve ionic and polar molecules b) The solid state is less dense than the liquid state c) Hydrogen bonds exist only in the solid state d) It has a high surface tension 24. Most important reason for the unusual properties of water is____. a) Water can be immediately ionized at room temperature b) The covalent bonding pattern in water molecule c) Hydrogen bonding between water molecules d) The bond angle between the two hydrogen atoms in water 25. Large bodies of water, such as lakes and oceans, do not quickly change in temperature. What is the reason for this phenomenon? a) Water is an acid b) Water has a high heat capacity c) Water shows cohesive behavior d) Water expands as it freezes 17 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 26. Why is water such a good solvent? 30. Which of the following effects is a) because of its high specific heat capacity produced by the high surface tension of b) because it is polar water? c) because it is liquid a) Organisms resist temperature changes, d) because of its low heat of vaporization although they give off heat due to chemical reactions 27. You place a bottle of water in the freezer. b) A water strider can walk across the The next morning, you open the freezer and surface of a small pond find that the bottle has burst. Which property c) Lakes don't freeze solid in winter, despite of water explains what happened? low temperatures a) Water molecules are cohesive d) Water flows upward from the roots to b) Water molecules are polar the leaves in plants c) Water molecules expand upon freezing d) Water is a universal solvent 31. Water makes up approximately 60% of the human body and plays a vital role in 28. Many mammals control their body regulating body temperature. Which temperature by sweating. Which property of property of water makes it good at water is most directly responsible for the regulating temperature? ability of sweat to lower body temperature? a) Water has an unusual crystalline structure a) water's ability to dissolve molecules in the air b) Water is a good solvent b) the release of heat by the formation of c) Water has a high capacity for heat hydrogen bonds d) Water shows strong cohesion c) the absorption of heat by the breaking of hydrogen bonds 32. A coastal climate is moderated d) water's change in density when it condenses primarily by which of the following properties of water? Water____. a) is the universal solvent 29. If you place the corner of a paper towel into b) has a high heat of evaporation a droplet of water the water moves across the c) is cohesive and adhesive paper towel. Which of the following would d) has a high surface tension explain the movement of the water? a) surface tension b) both cohesion and adhesion 33. The polarity of water molecules forms c) adhesion ____bonds. d) cohesion a) Ionic b) Both a and c c) Covalent d) Hydrogen 18 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 9 Acids and Bases ‫اﻷﺣﻤﺎض واﻟﻘﻮاﻋﺪ‬ 19 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Roles of Buffers in blood Carbonic acid is a weak acid and works as a buffer that helps keep blood pH within normal limits: This acid minimally dissociate: H2CO3 → H+ + HCO3- Carbonic acid Bicarbonate ion Blood contains both forms of this buffer. When H+ ions added to blood: HCO3- + H+ → H2CO3 When OH- is added to blood: H2CO3 + OH- → HCO3- + H2O These reactions prevent any significant changes in blood pH. 20 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 Practice questions Acids and Bases 34. When hydrochloric acid, a strong acid, is added to water, the PH of water____. a) Goes up b) Stays the same c) Goes down d) Goes first up and then down 35. The pH of your small intestines is around 7.5 and the PH of your large intestine can be 5.5. As substances travel from the small intestines to the large intestine, what would happen to the 𝑯+ ion concentration? a) It decreases 100-fold b) It increases by 100-fold c) It increases 10-fold d) It decreases 2-fold 36. One of the buffer that contribute to PH stability in human blood is carbonic acid (𝑯𝟐𝑪𝑶𝟑). Carbonic acid is a weak acid that dissociates into a bicarbonate ion (HC𝑶𝟑−) and a hydrogen ion (𝑯+). Thus, 𝑯𝟐𝑪𝑶𝟑 ↔ 𝑯𝑪𝑶𝟑− + 𝑯+ , if the pH of the blood drops, one would expect____. a) the concentration of bicarbonate ion (HCO3-) to increase b) the HCO3- to act as a base and remove excess H+ with the formation of H2CO3 c) a decrease in the concentration of H2CO3 and an increase in the concentration of HCO3- d) the HCO3- to act as an acid and remove excess H+ with the formation of H2CO3 37. What is the pH of a solution with a hydroxyl ion [OH-] concentration of 𝟏𝟎−𝟏𝟐𝑴 ? a) PH4 b) PH14 c) PH12 d) PH2 38. Which of the following pH values represents the lowest concentration of hydrogen ions? a) 12 b) 6 c) 9 d) 3 21 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 39. What is the pH of a solution with a hydroxyl ion [OH-] concentration of 𝟏𝟎−𝟏𝟐𝑴 ? a) PH4 b) PH14 c) PH12 d) PH2 40. Which of the following pH values represents the lowest concentration of hydrogen ions? a) 12 b) 6 c) 9 d) 3 41. A strong acid like HCl____. a) increases the pH when added to an aqueous solution b) reacts with strong bases to create a buffered solution c) is a strong buffer at low PH d) ionizes completely in an aqueous solution 42. Which of the following solutions would require the greatest amount of base to be added to bring the solution to neutral pH? a) tomato juice at pH 4 b) household bleach at pH 12 c) black coffee at pH 5 d) vinegar at pH 3 43. Consider two solutions: solution X has a pH of 4; solution Y has a pH of 7. From this information, we can reasonably conclude that____. a) solution Y has no free hydrogen ions (𝑯+). b) the concentration of hydrogen ions in solution X is 3 times as great as the concentration of hydrogen ions in solution Y. c) the concentration of hydrogen ions in solution X is 1,000 times as great as the concentration of hydrogen ions in solution Y d) the concentration of hydrogen ions in solution X is 30 times as great as the concentration of hydrogen ions in solution Y 44.The blood buffer reactions described by 𝑯𝟐𝑪𝑶𝟑 𝑯+ + 𝑯𝑪𝑶𝟑− indicates that____. a) any reaction in one direction causes an immediate reverse reaction b) scientists are uncertain which direction the equation flows c) chemicals can swing wildly from acid to basic d) the reaction can flow either direction depending on whether there is an excess of hydrogen or hydroxide ions 22 1ST Semester 2024 / 2025 Zahra Aman 36122821 BIOLS 102 45.A solution with a pH of 6 has ________ times _________ 𝑶𝑯− than a solution with a pH of 10. a) 40; more b) 𝟏𝟎𝟒; less c) 4000; less d) 4; less 46. Buffers are substances that help resist changes in pH by____. a) releasing 𝑯+ to a solution when acids are added b) releasing𝑶𝑯− to a solution when bases are added c) accepting 𝑶𝑯− from a solution when acids are added d)accepting𝑯+ from a solution when acids are added 47.If the concentration of hydrogen ions is 1 x 𝟏𝟎−𝟓, the PH is____. a) 10 b) 5 c) 14 d) 7 23