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Questions in chemistry

📝 Answered - The accepted value for the percent by mass of water in a hydrate is 36.0%. In a laboratory activity, a student determined the percent by mass of water in the hydrate to be 37.8%. What is the percent error for the student's measured value? (1) 5.0% (2) 4.8% (3) 1.8% (4) 0.05%

📝 Answered - Which condensed structural formula represents an unsaturated compound? 1. CH3CH=CHCH3 2. CH3CH2CH3 3. CH3CH3 4. CH4

📝 Answered - Given the balanced ionic equation: \[ 3\text{Pb}^{2+} + 2\text{Cr} \rightarrow 3\text{Pb} + 2\text{Cr}^{3+} \] What is the number of moles of electrons gained by 3.0 moles of lead ions? 1. 5.0 mol 2. 2.0 mol 3. 3.0 mol 4. 6.0 mol

📝 Answered - Which formula represents an organic compound? 1. CaH₂ 2. C₄H₈ 3. H₂O₂ 4. P₂O₅

📝 Answered - Which energy conversion must occur in an operating electrolytic cell? 1. Electrical energy to chemical energy 2. Electrical energy to nuclear energy 3. Chemical energy to electrical energy 4. Chemical energy to nuclear energy

📝 Answered - Which compound is classified as a hydrocarbon? 1. butanal 2. butyne 3. 2-butanol 4. 2-butanone

📝 Answered - Which element is a liquid at STP (Standard Temperature and Pressure)? 1. Bromine 2. Francium 3. Cesium 4. Iodine

📝 Answered - How many moles of water (H2O) would be produced if 10 moles of O2 gas reacted completely with excess H2 gas? \[2 \, \text{H}_2(g) + \text{O}_2(g) \rightarrow 2 \, \text{H}_2\text{O}(g)\] A. 5 B. 10 C. 20 D. 30

📝 Answered - Which chemical equation best describes the reaction of potassium metal with fluorine gas to form solid potassium fluoride? A. K(s) + F2(g) → KF2(s) B. K(s) + F(g) → KF(s) C. K2(g) + F2(g) → 2 KF(s) D. 2 K(s) + F2(g) → 2 KF(s)

📝 Answered - What is the color of the indicator thymol blue in a solution that has a pH of 11? A. red B. pink C. blue D. yellow