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Questions in chemistry

[Terjawab] 5. Which one of the following can be used as an acid-base indicator for a visually impaired student? a) Litmus b) Turmeric c) Vanilla essence d) Petunia leaves. 6. a) Acids and bases that you encounter in day-to-day life (any 3 from each). b) One strong acid and one weak acid. 7. a) Acid present in car batteries b) An antacid.

[Terjawab] From the reaction given below, write an ionic equation to show which substance is oxidized and reduced. a. [tex]Na ( s )+ CaCl _2[/tex] (aq) i. substance oxidized ii. substance reduced b. [tex]K ( s )+ AgNO _3( aq )[/tex] i. substance oxidized ii. substance reduced c. [tex]Mg ( s )+ CuSO _4( aq )[/tex] i. substance oxidized ii. substance reduced Balance the equation if necessary.

[Terjawab] Complete combustion of a 0.350 g sample of a compound in a bomb calorimeter releases 14.0 kJ of heat. The bomb calorimeter has a mass of 1.20 kg and a specific heat of [tex]$3.55 J /\left( g _{ i }{ }^{\circ} C \right)$[/tex]. If the initial temperature of the calorimeter is [tex]$22.5^{\circ} C$[/tex], what is its final temperature? Use [tex]$q=m C_p \Delta T$[/tex]. A. [tex]$19.2^{\circ} C$[/tex] B. [tex]$25.8^{\circ} C$[/tex] C. [tex]$34.2^{\circ} C$[/tex] D. [tex]$72.3^{\circ} C$[/tex]

[Terjawab] How does your body make this life saving trade? Your blood contains a buffer called sodium bicarbonate (NaHCO3). This weak base, produced in your body, is the same compound that is sold in the grocery store as baking soda. This compound reacts in an exchange reaction with strong acids to produce weak acids that contribute fewer hydrogen cations to a solution. Converting hydrochloric acid produced in your stomach to a weak acid raises your blood pH preventing acidosis. Complete the reaction below by writing the name of the weak acid in the blank. HCl + NaHCO3

[Terjawab] Consider the equation below. [tex]$CaCO_3(s) \longleftrightarrow CaO(s)+CO_2(g)$[/tex] What is the equilibrium constant expression for the given reaction? A. [tex]$K _{ eq }=\frac{[ CaO ]}{\left[ CaCO _3\right]}$[/tex] B. [tex]$K _{\text {eq }}=\frac{\left[ CO _2\right][ CaO ]}{\left[ CaCO _3\right]}$[/tex] C. [tex]$K _{\text {eq }}=\left[ CO _2\right]$[/tex] D. [tex]$K_{\text {eq }}=\frac{1}{\left[ CO _2\right]}$[/tex]

[Terjawab] An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

[Terjawab] The masses of two samples were measured. What is the total mass, reported to the appropriate number of significant figures? [tex]$24.964 g + 0.7643 g = [?] g$[/tex]

[Terjawab] Sulfuric acid is manufactured industrially by a four-step process as shown: Step 1: Sulfur is burned in excess air to produce sulfur dioxide. Step 2: Sulfur dioxide is converted into sulfur trioxide. Step 3: Sulfur trioxide is reacted with concentrated sulfuric acid to produce Substance Y. Step 4: Substance Y is reacted with water to produce concentrated sulfuric acid. (a) (i) Name the process used in the industrial manufacture of sulfuric acid. (ii) Identify substance Y produced in Step 3. (b) By writing the balanced chemical equation, describe how sulfur dioxide is converted into sulfur trioxide in Step 2.

[Terjawab] How many chlorine atoms are on the products side of the reaction [tex]2 Al +6 HCl \rightarrow 2 AlCl ^2+3 H _2[/tex]?

[Terjawab] A scientist has 100 milligrams of a radioactive element. The amount of radioactive element remaining after [tex]$t$[/tex] days can be determined using the equation [tex]$f(t)=100\left(\frac{1}{2}\right)^{\frac{t}{10}}$[/tex]. After three days, the scientist receives a second shipment of 100 milligrams of the same element. The equation used to represent the amount of shipment 2 remaining after [tex]$t$[/tex] days is [tex]$f(t)=100\left(\frac{1}{2}\right)^{\frac{t-3}{10}}$[/tex]. After any time, [tex]$t$[/tex], the mass of the element remaining in shipment 1 is what percentage of the mass the element remaining in shipment 2? A. 78.1 % B. 81.2 % C. 123.1 % D. 128.0%