Answer:
Models make some things easier to understand.
Measurements can be made only on models.
Models help scientists visualize things they can’t see.
Models are perfectly accurate representations of objects.
Scientists can analyze models to make predictions.
Explanation:
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<h3>
Answer:</h3>
1.1 × 10²² atoms Au
<h3>
General Formulas and Concepts:</h3>
<u>Chemistry</u>
<u>Atomic Structure</u>
- Reading a Periodic Table
- Using Dimensional Analysis
- Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.
<u>Math</u>
<u>Pre-Algebra</u>
Order of Operations: BPEMDAS
- Brackets
- Parenthesis
- Exponents
- Multiplication
- Division
- Addition
- Subtraction
<h3>
Explanation:</h3>
<u>Step 1: Define</u>
3.7 g Au
<u>Step 2: Identify Conversions</u>
Avogadro's Number
Molar Mass of Au - 196.97 g/mol
<u>Step 3: Convert</u>
<u />
= 1.13121 × 10²² atoms Au
<u>Step 4: Check</u>
<em>We are given 2 sig figs. Follow sig fig rules and round.</em>
1.13121 × 10²² atoms Au ≈ 1.1 × 10²² atoms Au
Answer:
Mechanical advantage = load/<u>effort</u>
Explanation:
Mechanical advantage is like a ratio of load to effort and many machines like pulleys depend on this relationship between load and effort for it to work.
Answer:
Phenolphthalein is an indicator. It is pink in alkaline solutions and turns colourless as the pH decreases.
It can be used to measure the activity of the enzyme lipase on the breakdown of lipids.
Samples of milk containing phenolphthalein were incubated with lipase at different temperatures.
The time taken for the phenolphthalein to turn colourless was recorded and used to calculate the rate of enzyme activity.
Figure 10 shows these results.
Picture
(a) (i) Explain why phenolphthalein turns colourless when lipase breaks down the lipids in milk. (2)
(ii) Describe the effect of temperature on the activity of lipase, as shown in Figure 10. (2)
(iii) Explain why the activity of lipase changes above a temperature of 40°C. (2)
(b) A student investigated the time taken for amylase to breakdown a 10% starch solution into glucose at 37°C. The student repeated the investigation five times.
After alpha decay (234,90) remain from it
