Question 1
| Element | Atomic radius (picometers) |
|---|---|
| Sodium | 186 |
| Magnesium | 160 |
| Aluminum | 143 |
| Silicon | 118 |
| Phosphorus | 110 |
| Sulfur | 103 |
| Chlorine | 99 |
The table gives the radii of atoms of Period 3 elements. Which explanation accounts for the pattern?
Regents Chemistry practice questions by topic
Original questions for all six topics, with worked explanations and feedback on written answers.
| Multiple choice | Worked, or in timed checks |
|---|---|
| Clusters | A phenomenon, data and several one-credit parts |
| Written answers | Read against the creditable answers, with your next step |
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Question 2
| Indicator | Color below the range | pH range of color change | Color above the range |
|---|---|---|---|
| Bromthymol blue | yellow | 6.0 to 7.6 | blue |
| Phenolphthalein | colorless | 8.2 to 10.0 | pink |
A lifeguard tests a sample of swimming pool water with two indicators (table). Bromthymol blue turns the sample blue, and phenolphthalein leaves it colorless. Which pH range fits both results?
Question 3
| Metal | Specific heat capacity (J/(g·°C)) |
|---|---|
| aluminum | 0.897 |
| iron | 0.449 |
| copper | 0.385 |
| lead | 0.129 |
To identify a metal, a student heats a 60.0 gram sample to 99.0 °C in boiling water and drops it into 120.0 grams of water at 21.0 °C in an insulated foam cup. The metal and the water both end at 24.4 °C. Assume all the heat lost by the metal is gained by the water. The specific heat capacity of water is 4.18 J/(g·°C). Using the table, which metal is the sample most likely to be?
Question 4
| Deicer | Melts ice at low temperature (weight 3) | Low cost (weight 2) | Low corrosion (weight 2) | Low harm to plants (weight 1) |
|---|---|---|---|---|
| rock salt (NaCl) | 3 | 5 | 1 | 1 |
| calcium chloride (CaCl2) | 5 | 3 | 2 | 2 |
| calcium magnesium acetate | 2 | 1 | 5 | 5 |
The county scores three deicers from 1 (poor) to 5 (excellent) on four criteria and gives each criterion a weight (table). Each score is multiplied by its weight and the products are added. Which deicer has the best weighted total?
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Are these past Regents questions?
No. Every question here is original, written for the current standards and checked by independent solvers.