Answer:
C a chemical has become a different color
Explanation:
is it a chemical change when water turns to ice? or to water vapor? no because it can easily change back.
it's not A obviously
I just explained why it's not B
and again it's obviously not D
It's C because once you change the color of something you can most likely not change it back (cake batter, stained glass) making it a chemical change
Answer:
3.10 × 10⁻⁴ mg
Explanation:
<em>In the Minnesota Department of Health set a health risk limit for benzene in groundwater of 10.0 μg/L. Suppose an analytical chemist receives a sample of groundwater with a measured volume of 31.0 mL. Calculate the maximum mass in milligrams of benzene which the chemist could measure in this sample and still certify that the groundwater from which it came met Minnesota Department of Health standards. Be sure your answer has the correct number of significant digits.</em>
Step 1: Given data
- Concentration limit (C): 10.0 μg/L
- Volume of the sample (V): 31.0 mL
Step 2: Convert "V" to L
We will use the conversion factor 1 L = 1000 mL.
31.0 mL × 1 L/1000 mL = 0.0310 L
Step 3: Calculate the maximum mass of benzene (m)
We will use the following expression.
m = C × V = 10.0 μg/L × 0.0310 L = 0.310 μg.
Step 4: Convert "m" to mg
We will use the conversion factor 1 mg = 1000 μg.
0.310 μg × 1 mg/1000 μg = 3.10 × 10⁻⁴ mg
First find the names of the acids end in “acid”. Acid formulas have one of these forms: HX(aq) or HaXbOc then find the Ionic compounds that contain hydroxide. (OH-) , carbonate (CO32-) , or hydrogen carbonate (HCO3-) anions are basic.