Chemistry Ch1 Lecture Practice
A patient requires an injection of 0.012 g of a painkiller available as a 15 mg/mL solution. How many mL of solution should be administered?
(0.012g) (1mg/0.001g) (1mL/15mg) = 0.80mL To determine the volume of the solution that should be administered, we can use the following equation: Volume (mL) = Mass (g) / Concentration (mg/mL) Given: Mass = 0.012 g Concentration = 15 mg/mL Let's substitute the values into the equation: Volume (mL) = 0.012 g / 15 mg/mL To ensure consistent units, we need to convert grams (g) to milligrams (mg): Volume (mL) = 12 mg / 15 mg/mL Simplifying the equation: Volume (mL) = 0.8 mL Therefore, 0.8 mL of the solution should be administered to the patient.
Convert the following values to scientific notation: (a)0.058 g (b)46,792 m (c)0.006072 cm (d)345.3 kg
(a) 0.058 g in scientific notation is 5.8 x 10^(-2) g. (b) 46,792 m in scientific notation is 4.6792 x 10^4 m. (c) 0.006072 cm in scientific notation is 6.072 x 10^(-3) cm. (d) 345.3 kg in scientific notation is 3.453 x 10^2 kg.
Identify the number of significant figures (sig figs) in each of these values. 0.010, 0.07, 0.05002, 0.550, 7.010, 725.00, 90.0
1 sigfig: 0.07 2 sigfig: 0.010 3 sigfigs: 0.550, 90.0 4 sigfigs: 7.010, 0.05002 5 sigfigs: 725.00 The rules for counting significant figures are: Nonzero digits are always significant. Leading zeros are never significant. Trailing zeros are significant if a decimal point is shown in the number, but may or may not be significant if no decimal point is shown. By convention, it is assumed that trailing zeros without a decimal point are not significant. Zeros that are between nonzero digits are always significant. Recall that leading zeros are those that come before all the nonzero digits, but not necessarily before the decimal point, and that trailing zeros are those that come after all the nonzero digits, but not necessarily after the decimal point. The number 0.07 has only one significant figure. None of the zeros are significant because they are all leading zeros, which are never significant. The number 0.010 has two significant figures. Leading zeros are never significant; however, the trailing zero is significant because a decimal point is shown in the number. The number 0.550 has three significant figures. Leading zeros are never significant; however, the trailing zero is significant because a decimal point is shown in the number. The number 90.0 has three significant figures. The trailing zeros are significant because a decimal point is shown in the number. The number 7.010 has four significant figures. All of the zeros are significant. The trailing zero is significant because a decimal point is shown in the number, and the remaining zero is significant because it is between nonzero digits. The number 0.05002 has four significant figures. Zeros between nonzero digits are always significant and leading zeros are never significant. The number 725.00 has five significant figures. All of the zeros are significant. The trailing zeros are significant because a decimal point is shown in the number.
Ex) Classify each of the following matter. (Element, compound, homo mixture, hetero mixture) 1.Coffee solution 2.Glucose 3.A lead weight 4.Water 5.Ethanol 6.Air 7.Olive oil 8.Blood sample 9.Neon gas 10.Table salt
1. Homogeneous mixture 2. Compound 3. Element 4. Compound (Water is not an element; it is a compound. A compound is a substance composed of two or more different elements chemically bonded together. Water, chemically represented as H2O, consists of two hydrogen (H) atoms bonded to one oxygen (O) atom. In contrast, an element is a pure substance composed of identical atoms. Each element on the periodic table is made up of only one type of atom. For example, oxygen (O) and hydrogen (H) are elements, but water (H2O) is a compound formed by the combination of these elements.) 5. Compound 6. Homogeneous mixture ( same composition of components throughout mixture » 7. Homogeneous mixture ( because you cannot visibly distinguish between carbon and chainlengths) 8. Heterogeneous mixture because the blood cells are physically separate from the blood plasma.) 9. Element 10. Compound unless dissolved in any appropriate solventlikewater then its homogeneous)
Steve races to the nearest taco stand at lunchtime and sees that his pedometer recorded his peak speed at 109.9 cm/s. What was Steve's peak speed in kilometers per hour?
3.96 km/h To convert Steve's peak speed from centimeters per second (cm/s) to kilometers per hour (km/h), we need to perform the following conversions: 1 kilometer = 1000 meters 1 hour = 3600 seconds First, we'll convert centimeters to kilometers: 109.9 cm/s * (1 m / 100 cm) * (1 km / 1000 m) = 0.001099 km/s Next, we'll convert seconds to hours: 0.001099 km/s * (3600 s / 1 hour) = 3.9564 km/h Therefore, Steve's peak speed is approximately 3.96 km/h (rounded to two decimal places). Certainly! Speed is a measure of how quickly an object moves. It is defined as the distance traveled per unit of time. In this case, we are converting Steve's peak speed from centimeters per second to kilometers per hour. To perform the conversion, we use conversion factors to convert the units. In the metric system, there are relationships between various units that allow us to convert from one unit to another. In this conversion, we start with Steve's peak speed of 109.9 cm/s. We first convert centimeters to meters by multiplying by the conversion factor of 1 m/100 cm. This gives us the speed in meters per second. Next, we convert meters per second to kilometers per second by multiplying by the conversion factor of 1 km/1000 m. This gives us the speed in kilometers per second. Finally, we convert seconds to hours by multiplying by the conversion factor of 3600 s/1 hour. This converts the speed from kilometers per second to kilometers per hour, which is a more commonly used unit for measuring speed in everyday situations. The final result of approximately 3.96 km/h means that Steve's peak speed, as recorded by his pedometer, was approximately 3.96 kilometers per hour. This tells us how fast he was moving relative to distance and time. Four conversion factors are needed to convert 109.9 cm/s to the equivalent speed in kilometers per hour. Recall that 1 m=100 cm and 1 km=1000 m. Also there are 60 s in 1 min and 60 min in 1 h. Use the conversion factors to simultaneously convert centimeters per second to kilometers per hour. Arrange the conversion factors so that all units besides kilometers and hours cancel out. 109.9cms×1 m100 cm×1 km1000 m×60 s1 min×60 min1 h=3.956kmh
To how many significant figures should each answer be rounded? equation A: (6.626× 10−34 J⋅s)(2.9979× 108 m/s)4.550×10−7 m=4.365733054945×10−19 J(unrounded) After rounding, the answer to equation A should have
4 sig figs because 6.626 has 4 sigfigs, 2.9979 has 5, and 4.550 has 4 sigfigs. For dividing and multiplying you round to the smallest number of sigfigs in the equation: for this one it's 4 and not 5.
Suppose that you weigh 74 kg before dinner. How much will you weigh after dinner if you eat 1.56 kg of food?
74. kg + 1.56 kg =. 75.56 kg 3sigfigs so... =. 75.6 kg
You just competed in a track meet and you ran the 1500 m race in 417 s. What was your average speed in miles per hour?
8.057 miles per hour. To calculate your average speed in miles per hour (mph) based on the distance of 1500 meters and the time of 417 seconds, we need to perform the following conversions: 1 mile = 1609.34 meters 1 hour = 3600 seconds First, we'll convert meters to miles: 1500 m * (1 mile / 1609.34 m) = 0.9321 miles Next, we'll convert seconds to hours: 417 s * (1 hour / 3600 s) = 0.1158 hours Finally, we'll calculate the average speed in miles per hour: 0.9321 miles / 0.1158 hours = 8.057 mph Therefore, your average speed in the 1500 m race was approximately 8.057 miles per hour. Use 1 mi=1.609 km for the English to metric conversion. Other helpful conversion factors include 1 hr=60 min=3600 s and 1 km=1000 m. Use the conversion factors to simultaneously convert meters per second to miles per hour. Be sure that all units other than miles and hours cancel out. 1500m417s×1km1000m×1mi1.609km×60s1min×60min1hr=8.05 mph.
Compound properties
A compound is made up of multiple types of elements that are chemically bonded to each other. In the diagram, this is represented by groups of differently colored spheres that are "stuck together." Since all the groups are the same, it is a pure substance, rather than a mixture.
Heterogeneous mixture properties
A mixture can be either homogeneous or heterogeneous. A homogeneous mixture is one in which the components are evenly distributed. Any region within the mixture is chemically the same as another region. In a heterogeneous mixture, the composition varies from one region to another because the components are not evenly distributed. Cereal in milk, ice in soda, physically possible to separate due to its non uniform composition
Homogeneous mixture properties
A mixture is a physical combination of two or more elements and compounds. Examples of mixtures include an element and a compound, two different compounds, or two different elements that are not chemically bonded to each other. In the diagram, this is represented by differently colored spheres, or differently colored groups of spheres. Cannot be seen with the naked eye or even under a microscope - salt dissolved in water
Element Properties
A pure substance is composed of one type of atom or molecule. Both elements and compounds are classified as pure substances. An element is made up of only one type of atom. In the diagram, this is represented by showing only one color of sphere.
Accuracy...
Accuracy describes how close groups of measurements is/are to an accepted value.
Which of the following are mixtures? A. water (H2O) B. salt water C. air (mostly N2 and O2) D. salt (NaCl)
B and C. Pure substances can be represented by a single chemical formula. In contrast, mixtures require multiple chemical formulas to represent their composition. Salt is a pure substance because it can be represented by a single chemical formula, NaCl. Water is a pure substance because it can be represented by a single chemical formula, H2O. Salt water would need more than one chemical formula to describe its compositon, NaCl and H2O, so it is a mixture. Air, rather than being a compound of nitrogen and oxygen, is a mixture of nitrogen and oxygen as indicated by its two distinct chemical formulas, N2 and O2. Examples of compounds of nitrogen and oxygen include NO and NO2.
You are conducting a study on the effects of carrot consumption on blood pressure. You will be giving carrots to participants in your study and monitoring their blood pressure over several months. Which of the following variable would be the simplest parameter to control (independent variable)? a) The participant's heart rate. b) The amount of carrots consumed by the participant. c) The participant's blood pressure. d) The participant's exposure to stress. e) The participant's age.
B. Amount of carrots. In this study, the simplest parameter to control (independent variable) would be the dosage or amount of carrots given to the participants. By keeping the dosage consistent and controlled, you can observe the effects of carrot consumption on blood pressure more accurately. Controlling the dosage ensures that any changes in blood pressure can be attributed to the carrot consumption and not to varying amounts of carrot intake. Other variables such as the participants' age, gender, lifestyle, or pre-existing health conditions may be more challenging to control, but by maintaining a consistent carrot dosage, you can isolate the impact of carrot consumption on blood pressure.
Which of these mixtures are heterogeneous? A. salt and water B. brass (an alloy of copper and zinc) C. granite (a type of rock with multicolor spots) D. oil and water
C and D. A homogeneous mixture is a physical combination of two or more subtances that has a uniform composition throughout. A heterogeneous mixture is a physical combination of two or more substances that has a nonuniform composition. When oil and water are mixed in a cup, two distinct layers form. The liquid at the top of the cup will look distinctly different than the liquid at the bottom of the cup. Therefore a mixture of oil and water is a heterogeneous mixture. When salt and water are mixed, the salt completely dissolves in the water to form a solution. The liquid in any area of the cup will look exactly the same as the liquid in any other area of the cup. Therefore a mixture of salt and water is a homogeneous mixture. Brass, an alloy of copper and zinc, is a mixture of metals that looks completely uniform to the human eye because the two components are well mixed down to the molecular level. Brass is therefore a homogeneous mixture. The different minerals that make up granite are visible as different colored spots in the rock. Granite is therefore an example of a heterogeneous mixture.
Which of the changes are chemical changes? A. Sugar is dissolved in water. B. A warm soda bottle fizzes when opened. C. The copper roof turns green over time. D. Baking soda is dissolved in vinegar and bubbles form. E. A fog appears on the windshield in cold weather.
C and D. Copper turning green and bubbles being formed when baking soda dissolves in vinegar are examples of chemical changes. The green coating on a copper roof, called the patina, is copper carbonate and other copper compounds formed from the copper. The bubbles formed when baking soda is dissolved in vinegar is carbon dioxide. The carbon dioxide was not a dissolved gas but was formed from the reaction of baking soda, sodium bicarbonate, with vinegar, acetic acid. Dissolving sugar in water forms a sugar solution. The chemical nature of the sugar and water do not change, and the sugar can be recovered by evaporating away the water. This is a physical change. A warm soda fizzes when opened because it contains dissolved carbon dioxide under pressure, and when the pressure is released the carbon dioxide bubbles form. This is a physical change. Fog appearing on the windshield is from the moisture in the air, which is water in a gaseous form, condensing to a liquid. A new substance has not formed, so this is a physical change.
chemical change
Combine or separate the elements
Electrical
Energy derived from moving charged particles
Chemical
Energy derived from substances reacting and bonds being made or broken
Mechanical
Energy derived from the position and movement of an object
Radiant
Energy derived from the visible and invisible electromagnetic spectrum
Put the steps in order to describe an experiment that follows the scientific method.
First Make initial observation Form initial hypothesis Test initial hypothesis Testing discredits the initial hypothesis Revise hypothesis Test revised hypothesis Testing confirms the revised hypothesis The revised hypothesis may eventually become a theory Last
If the density of an element/gas is less than the density of the fluid, it will...
Float
Classify each property as intensive or extensive. Boiling point , density, mass, temperature, volume, length, color, hardness
Intensive - boiling point, density, temp, color, hardness Extensive - mass, volume, length An intensive property is independent of the amount of substance present. An extensive property depends on the amount of substance present. Weight (mass), length, and volume are all extensive properties because they depend on the amount of substance present. For example, a large sample of salt would weigh more than a small sample of salt. Boiling point, melting point, density, temperature, color, and hardness are all intensive properties because they do not depend on the amount of substance present. For example, a large sample of salt is the same color as a small sample of salt.
If the density of an element/gas is the same as the density of the fluid, it will...
Not float or sink.
Will it float or sink? Object 1: 0.4g/mL Object 2: 2.7g/mL - both objects in water
Object 1 will float because it is less dense than water (1.00g/mL density) compared to object 2 which will sink because it is more dense than water If an object is more dense than water it will sink when placed in water, and if it is less dense than water it will float. If the density of the object is greater than the density of the fluid, the object's buoyant force will be less than the force of gravity and will sink. If the density of the object is less than the density of the fluid, the object's buoyant force will be greater than the force of gravity and will float.
Objects A and B have the same volume, but A has a greater mass. Which is denser?
Object A. Why? The object with the smaller volume will be more dense than the one with the larger volume. Density is defined as mass per unit volume, so if two objects have the same mass but different volumes, the one with the smaller volume will have a higher density because its mass is concentrated in a smaller space. So, if two objects have the same volume but different masses, the one that has a greater mass will have a higher density.
Objects C and D have the same mass, but C is larger. Which is denser?
Object D. Why? Density is defined as the mass of an object divided by its volume. Mathematically, density (ρ) is represented as: ρ = mass / volume If two objects have the same mass but different volumes, the object with the smaller volume will have a higher density. This is because density is inversely proportional to volume. When the mass is constant and the volume decreases, the density increases. Similarly, when the volume increases, the density decreases. So, in your scenario, the object with the smaller volume will be more dense than the one with the larger volume.
Classify each property as physical or chemical. Melting point, flammability, color, conductivity, susceptibility to rust, boiling point
Pp- melting point, color, conductivity, boiling point Cp-flammability, susceptibility to rust Physical properties can be measured without the composition of the substance changing. The color, melting point, conductivity, and boiling point of a substance are all physical properties because they can be tested without changing the chemical composition (i.e., without a chemical reaction occurring). When a substance melts or boils, it undergoes a phase change, not a chemical change. It still has the same chemical composition whether it is a solid, liquid, or gas. Measuring chemical properties requires creating new chemical substances through a chemical reaction. Iron in the presence of oxygen and water reacts to form iron oxide, or rust; therefore, susceptibility to rust is a chemical property. Methane, CH4, when burned in the presence of oxygen, reacts to form carbon dioxide and water; therefore, flammability is also a chemical property.
Precision...
Precision describes how close groups of measurements is/are to each other.
Both objects have different volumes but the same mass, which is more dense, Object A or B? Object A: A solid cube with a side length of 2 cm Object B: A solid cube with a side length of 4 cm
Since both objects have the same mass, we can assume that they are made of the same material. To calculate the volume of a cube, we use the formula: Volume = side length x side length x side length For Object A: Volume = 2 cm x 2 cm x 2 cm = 8 cm³ For Object B: Volume = 4 cm x 4 cm x 4 cm = 64 cm³ Now let's calculate the density. We'll assume a mass of 100 grams for both objects for simplicity. For Object A: Density = mass / volume = 100 g / 8 cm³ = 12.5 g/cm³ For Object B: Density = mass / volume = 100 g / 64 cm³ = 1.56 g/cm³ As you can see, even though Object A has a smaller volume, it has a higher density (12.5 g/cm³) compared to Object B (1.56 g/cm³). This example demonstrates that when two objects have the same mass but different volumes, the object with the smaller volume will have a higher density.
If the density of an element/gas is greater than the density of the fluid, it will...
Sink
physical change
Solid, liquid, air, separate the layers
Mercury, also known as quicksilver, is a metallic element and a liquid at room temperature. Calculate mercury's density if a sample of mercury is found to have a mass of 505.0 g and a volume of 37.05 mL.
To calculate the density of mercury, we use the formula: Density = Mass / Volume Given that the mass of the mercury sample is 505.0 g and the volume is 37.05 mL, we can substitute these values into the formula: Density = 505.0 g / 37.05 mL To ensure consistent units, we need to convert the volume from milliliters (mL) to grams (g) since 1 mL of water is equivalent to 1 gram. Density = 505.0 g / 37.05 g = 13.63 g/mL Therefore, the density of mercury is approximately 13.63 g/mL.
Ethanol is a common laboratory solvent and has a density of 0.789 g/mL. What is the mass, in grams, of 127 mL of ethanol?
To calculate the mass of ethanol, we can use the formula: Mass = Density * Volume Given that the density of ethanol is 0.789 g/mL and the volume is 127 mL, we can substitute these values into the formula: Mass = 0.789 g/mL * 127 mL Mass = 100.203 g Therefore, the mass of 127 mL of ethanol is 100.203 grams.
The mass of fuel in a jet must be calculated before each flight to ensure that the jet is not too heavy to fly. A Boeing 747 is fueled with 173,231 L of jet fuel. If the density of the fuel is 0.768 g/ml, what is the mass of the fuel in kilograms?
To calculate the mass of the fuel, we can use the formula: Mass (g) = Volume (L) x Density (g/mL) Given: Volume = 173,231 L Density = 0.768 g/mL First, we need to convert the volume from liters (L) to milliliters (mL) since the density is given in grams per milliliter: Volume (mL) = 173,231 L x 1000 mL/L = 173,231,000 mL Now, we can substitute the values into the formula: Mass (g) = 173,231,000 mL x 0.768 g/mL Calculating the result: Mass (g) = 133,045,008 g Finally, to convert the mass from grams (g) to kilograms (kg): Mass (kg) = 133,045,008 g / 1000 = 133,045.008 kg Therefore, the mass of the fuel in the Boeing 747 is approximately 133,045.008 kilograms.
What is 98.6°F (normal body temperature) on the Celsius scale?
To convert 98.6°F to Celsius, you can use the following formula: °C = (°F - 32) / 1.8 Let's substitute 98.6°F into the formula: °C = (98.6 - 32) / 1.8 Simplifying the equation: °C = 66.6 / 1.8 Calculating the result: °C ≈ 37°C Therefore, 98.6°F is approximately equal to 37°C, which is considered the normal body temperature on the Celsius scale.
The surface temperature on Venus may approach 745 K. What is this temperature in degrees Celsius?
To convert a temperature from Kelvin (K) to degrees Celsius (°C), you can use the following formula: °C = K - 273.15 Given that the surface temperature on Venus is approximately 745 K, we can substitute this value into the formula: °C = 745 K - 273.15 °C = 471.85°C Therefore, the temperature on Venus, which is approximately 745 K, is equivalent to approximately 471.85 degrees Celsius.
Convert 187.9 ∘F to kelvins.
To convert a temperature from degrees Fahrenheit (°F) to Kelvin (K), you can use the following formula: K = (°F + 459.67) × 5/9 Given that the temperature is 187.9 °F, we can substitute this value into the formula: K = (187.9 + 459.67) × 5/9 K = (647.57) × 5/9 K ≈ 359.76 K Therefore, the temperature of 187.9 °F is equivalent to approximately 359.76 Kelvin.
The temperature on Mercury may drop to −265 °F at night. What is this temperature in degrees Celsius?
To convert a temperature from degrees Fahrenheit (°F) to degrees Celsius (°C), you can use the following formula: °C = (°F - 32) × 5/9 Given that the temperature on Mercury may drop to -265 °F at night, we can substitute this value into the formula: °C = (-265 - 32) × 5/9 °C = (-297) × 5/9 °C ≈ 165 Therefore, the temperature on Mercury, which can drop to approximately -265 °F at night, is equivalent to approximately -147.22 degrees Celsius.
A liquid has a volume of 0.0031 L. Convert this volume to cubic centimeters.
To convert the volume of a liquid from liters (L) to cubic centimeters (cm³), we need to use the conversion factor: 1 liter (L) = 1000 cubic centimeters (cm³) Given that the liquid has a volume of 0.0031 L, we can multiply this value by the conversion factor to obtain the volume in cubic centimeters: 0.0031 L * 1000 cm³/L = 3.1 cm³ Therefore, the volume of the liquid is 3.1 cubic centimeters.
When added to water, octane will form an upper layer on the surface of the water. Iron wil sink when added to water. Rank the densities of these substances from lowest to highest.
When comparing the densities of substances, we can rank them from lowest to highest. In this case, we have: 1. Water: Water has a density of approximately 1 g/cm³ at standard conditions. 2. Octane: Octane, a hydrocarbon, has a lower density than water. It has a density of approximately 0.7 g/cm³, making it less dense than water. Therefore, octane would float on the surface of water, forming an upper layer. 3. Iron: Iron is a metal and has a higher density than both water and octane. The density of iron is approximately 7.9 g/cm³, making it significantly denser than both water and octane. When added to water, iron would sink due to its higher density. So, the ranking of densities from lowest to highest would be: Octane < Water < Iron.
