STEM 11 1.How many moles of carbon dioxide does 250 grams of the substance have? How many molecules of CO2 are there?
2. Determine the percent composition of each element in the compound in tartaric acid (C4H6O6)
3. What are the empirical and molecular formula of a compound that is 40.27% potassium, 26.78%
chromium, and 32.95% oxygen?
4. Balance the following equations
1. _ C + _ O2 → ___ CO
2. _ Mg + _ O2 → _ MgO
3. _ H2O2 → _ H2O + _ O2
4. _ CH4 + O2 → _ CO2 + _ H2O
5. _ N2O5 → _ N2O4 + _ O2

What was bohr’s contribution to the planetary model

Amixture that has two or more substances that are spread out evenly is called a. compound b. heterogeneous c. substance d. homogeneous

1. an experiment in your science class lists the materials needed for the lab. it is your job, as a lab partner, to measure out 25 ml of distilled water and 2.5 grams of magnesium. what lab measuring tools would you choose to measure each substance and how would you use each tool to get the correct amounts? be sure to describe the process you would follow step-by-step. (5 points) 2.which of the following is an si base unit for measuring mass? (2 points) ampere gram meter pound 3.which of the following is an si base unit for time? (2 points) decades hours minutes seconds 4.which of the following tools should a scientist use to measure an object in milligrams? (2 points) graduated cylinder pan balance tape measure thermometer 4.which of the following tools should a scientist use to measure an object in milligrams? (2 points) graduated cylinder pan balance tape measure thermometer. 5.a pencil beside a metric ruler. the ruler is scaled from 1 centimeter to 10 centimeters, with markings for millimeters between each number. one end of the pencil is beside the 0 on the ruler, and the pencil point is beside the 5. which of the following measurements is accurate but not precise? (2 points) 5 mm 5 cm 50 mm 50 cm 6. which of the following prefixes represents the largest value? (2 points) giga hector kilo milli 7. which of the following types of graphs is best for plotting the percentages of a whole value in a data set? (2 points) bar graph circle graph histogram line graph