Students in a chemistry class added 5 g of Zinc (Zn) to 50 g of hydrochloric acid (HCl). A chemical reaction occurred that produced zinc chloride (ZnCl2) and 6 g of hydrogen gas (H2).
Zn+ 2HCl → ZnCl2+H2
What is the mass of the zinc chloride?
Answer: 11 g
Explanation:
Zn + 2HCl → ZnCl₂ + H₂
Number of moles of Zn:
Number of moles = 5 g / 65.38 g/mol
Number of moles = 0.08 mol
Number of moles of HCl :
Number of moles = 50 g / 36.5 g/mol
Number of moles = 1.4 mol
Compare the moles of both reactant with zinc chloride:
Zn : ZnCl₂
1 : 1
0.08 : 0.08
HCl : ZnCl₂
2 : 1
1.4 : 1/2×1.4 =0.7 mol
The number of moles of zinc chloride produced by Zn are less so it will limit reactants.
Mass of zinc chloride:
Mass = 0.08 mol × 136.3 g/mol
Mass = 11 g
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A glowstick works when two chemicals in the glowstick mix and have a chemical reaction that produces certain products and light.
1.Explain how you know that a chemical reaction is occurring within the glowstick.
2.Explain, on the molecular level, why a warm glowstick glows brighter than a cold glowstick.
3.Explain how this demonstrated the conservation of energy in chemical reactions.
Joey is conducting an experiment in which he measures how far a rubber ball flies when launched at different angles.
Which of the following lab tools will allow Joey to record his results?
A.
a lab journal
B.
a meter stick
C.
a spring scale
D.
a stopwatch
Answer:
A; lab journal
Explanation:
i just did it
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Which of the following is true of a balanced equation?
1.The kinds of atoms remain the same.
2.The number of atoms per molecule remains the same.
3.The total number of molecules remains the same.
4.The number of atoms of each element remains the same
Answer:
3
Explanation:
b/c a balanced chemical equation is
Answer:The number of products should be equal to the number of reactants. The properties of products should be the same as the properties of reactants. There must be as equal number of compounds on both sides of the equation. There must be as equal number of atoms of each element on both sides of the equation.
Explanation:
question #5: corals are sensitive to temperature . if temperatures are raised , it will cause the coral to bleach . what does bleach mean ? And can corals recover ?
Answer:
coral bleaching is when the temperature of the water changes (even slight changes in temperature effect coral) and the coral reacts negatively to it causing it to die. unfortunately corals cannot recover once they have been bleached.
Scientists often repeat experiments multiple times.
Why is this important?
A.
Repeating an experiment helps to verify the results.
B.
Repeating an experiment turns a hypothesis into a theory.
C.
Repeating an experiment gives scientists something to do while they think of new hypotheses.
D.
Repeating an experiment allows scientists to test different variables.
Answer:
The answer is A.
Explanation:
Scientists repeat the same experiments because they wanna try to see if they keep getting the same result. When a scientific investigation is repeated, this is called replication. Replication is important in science so scientists can “check their work.” The result of an experiment is not likely to be well accepted unless the investigation is repeated many times and the same result is always obtained.
Soda Caffeine Experiment
Scientists at a soft drink company want to test the effect of caffeine on heart rates,
They set up 3 groups of 50 people each.
All 150 people have their heart rates recorded before beginning the experiment,
Group 1 is given a non-caffeinated soda to drink.
Group 2 is given a regular caffeinated soda to drink,
Group 3 is given a highly caffeinated soda to drink,
The heart rate is recorded after each group has drank their soda,
What is the independent (or manipulated) variable in this experiment?
A. Amount of caffeine in soda
B. Change in heart rate
C. Amount of sugar in soda
D. Amount of movement by people before heart rate is recorded
plz helppppppppp meeeeeeeeeeeeeeee
4. Obsidian - rapid cooling when lava flows into water.
Granite - very slow cooling such as what occurs when magma is trapped beneath Earth's surface.
Basalt - cooling when lava flows over land
5. They are slightly simplistic and rock formation is not limited to only these methods.
6. They give a general overview of how a certain type of rock may be formed and how to identify them from a basic level based on their location.
please help!
a b c or d
Answer:
A glass pane / A.
Explanation:
Examples of insulators include plastics, Styrofoam, paper, rubber, glass and dry air. The division of materials into the categories of conductors and insulators is a somewhat artificial division.
Answer:
the answer is A
Explanation:
Are the orbits of the planets could you pls help!!!! Pls don't send scam links !! in the solar system as they revolve around the Sun perfectly
circular?
Explain.
Answer: Orbits are elliptical, Sun is in focal point of the ellipse.
Explanation:
Orbits are not perfect circles. Distance of Earth from Sun is between
147 million kilometres - 152 million kilometres. When Earth is in closest point of the Sun it moves faster tant in the point which is most far away from Sun.
Kepler´s Laws give more information.
Order the following from smallest to largest. Place the smallest value at the top of your list.
0.1km
10cm
10,000mm
1m
According to unit conversion, the values from smallest to largest are 10 cm, 1m,10,000mm,0.1 km.
What is unit conversion?Unit conversion is defined as a multi-step process which involves multiplication or a division operation by a numerical factor.The process of unit conversion requires selection of appropriate number of significant figures and the rounding off procedure.
It involves a conversion factor which is an expression for expressing the relationship between the two units.A conversion ratio always has value which equals to one which indicates that numerator and denominator have values which are expressed in different units.
It is an easy process which involves unit conversion between the different conversion systems. While unit conversion care needs to be taken regarding accuracy and precision.
As 0.1 km=100 m, 10 cm=0.1 m,10,000 mm=10 m and 1 m. Therefore the values from smallest to largest are 10 cm, 1 m,10,000 mm,0.1 km.
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Please help urgent !!! How does an instant cold pack get cold so quickly?
Answer:
When the inner bag of water is broken by squeezing the package, it dissolves the solid in an endothermic reaction. This reaction absorbs heat from the surroundings, quickly lowering the pack's temperature.
Explanation:
Uh, yea.
Have a good day!
Choose any electromagnetic wave we have discussed and write ONE PARAGRAPH telling me about the uses/benefits of that electromagnetic wave.
Which human body system creates the force that allows the body to move?
A.
musculoskeletal system
B.
nervous system
C.
respiratory system
D.
circulatory system
Low-pressure air is associated with which of the following?
a. Cold, Dry, High Density, Good Weather
b. Warm, Moist, Humid, Low Density, Good Weather
c. Cold, Dry, High Density, Bad Weather
d. Warm, Moist, Humid, Low Density, Bad Weather
IF YOU GIVE A LINK OR DON"T ACTUALLY ANSWER THIS QUESTION RIGHT JUST FOR POINTS I WILL REPORT YOUR ANSWER AND YOU
On the way to school, Ellie sat on a bench waiting for her friend. She noticed snow all around her. Later that day, Ellie and her friend walked home and passed the same bench. Ellie's friend said, “There is a puddle in front of the bench. It must have rained while we were in school, creating this puddle.”
Ellie disagreed. She had a different claim about how the puddle formed based on the evidence from her observations. Ellie's evidence was as follows:
The park was covered in snow that morning but not in the afternoon.
Ellie didn’t need her jacket on the way home because it was so warm.
It was sunny all day.
Do you think the puddle was formed from rain? Why or why not?
Answer:
No, the puddle was formed because of the sun, because if there was snow and it rained then it would have turned slippery or icy
Scientists can use many strategies during investigations, including heldwork, surveys,
models, and experiments. Which of these phrases best describes an experiment?
A mathematical analysis of data
B. observation of animals in their natural world
Ci collection of data from an uncontrolled environment for comparative purposes
D. procedure with controlled conditions and test and outcome variables
Answer:
D
Explanation:
Question: Scientists can use many strategies during investigations, including heldwork, surveys,
models, and experiments. Which of these phrases best describes an experiment?
A mathematical analysis of data
B. observation of animals in their natural world
Ci collection of data from an uncontrolled environment for comparative purposes
D. procedure with controlled conditions and test and outcome variables
Answer the question below pls
Answer:
The answer would be at 120°C
HELPPP this is a k12 so any links or false with be blocked or banned
Answer:
Sea level rise is caused by several different processes, including melting ice. But one big contributor to sea level rise is increasing global temperatures, which heat seas and cause something called thermal expansion of water. Thermal expansion happens when water gets warmer, which causes the volume of the water to increase. About half of the measured global sea level rise on Earth is from warming waters and thermal expansion.
Explanation:
I hope this helps
_Au2S3 + _H2---> _Au + _H2S
Question 3 options:
A- 1, 3, 2, 3
B- 1, 2, 4, 2
C- 1,3,1,2
D- 2, 1, 1, 3
Create a 10 question test to assess important topics on weathering, erosion and deposition. you may make multiple choice, fill in the blank and open ended questions. provide the right answers to assist you.
Answer:
Sorry i dont know the answers :(
Explanation:
Pls dont report me
Identify all the examples that support the Law of Conservation of Mass through chemical changes.
A. Steam rising off a pot of boiling water
B. Carbon Dioxide being produced by mixing Baking Soda and Vinegar
C. Carbon Monoxide released when the engine of a car burns fuel
D. Adding food coloring to frosting
E. Bread dough rising in a baker's oven
PLZ HURRY WILL MARK BRAINLIEST
Answer:
B
C
Explanation:
NNNOOOOOOOOOO LLLIIIINNNKKKKKKKKSSSSSSS Plastic takes more than ________ years to degrade.
A. 450 years
B. 300 years
C. 350 years
D. 400 years
Explanation:
The right option should be a
science homework help !!
1. list 2 objects that produce gamma rays in space
2. list 2 ways gamma rays are produced on earth
3. how do scientists use gamma rays?
correct answer gets brainliest !! :D
Answer:
1. They are produced by the hottest and most energetic objects in the universe, such as neutron stars and pulsars, supernova explosions, and regions around black holes.
2. On Earth, gamma waves are generated by nuclear explosions, lightning, and the less dramatic activity of radioactive decay.
3. Scientists can use gamma rays to determine the elements on other planets.
Explanation:
the explanation is above lol
The arrangement of things in the order that they occurred.
A. Extinction
B. chronological order
Science (Ignore chemistry subject pls)
Use the chart to answer the following question. I Nuclear energy does not produce dangerous waste products. Nuclear energy is significantly cheaper then production of energy from fossil II fuels. Nuclear energy does not produce greenhouse gases that contribute to global III warming Nuclear energy generates radioactive waste products that can be safely, IV cheaply, and easily stored, Which statements are claims that are supported by accurate evidence related to nuclear power O A. I, II, and III O B. I, III, and IV O C. II, III, and IV O D. I, II, and IV
Answer:
Nuclear energy is significantly cheaper then production of energy from fossil II fuels
Explanation:
The noble gases are unreactive and stable. Which of the following explains why this is true?
They have 8 electrons in their outer shell (except for Helium).
They exist on their own without other elements.
They have more electrons than other elements.
They each have no electrons.
EXPLAIN
Answer:
The answer is A. They have 8 electrons in their outer shell (except for Helium).
Explanation: This is because of the number of valence electrons( the amount of electrons in their outer shell). For a reaction to take place, a transfer of electrons must take place. If their outer shell is already full, they don't have any tendencies to react.
Noble gases are unreactive gases and are stable. This is because they have complete octet or eight electrons in their outer shells. Thus, option A is accurate.
What are noble gases?Noble gases are the gases of the periodic table that do not show any reaction with other elements and have great stability and low reaction rates.
They are special as their outermost orbit is completely filled to complete their octet rule so they lack any free electron to take part in a chemical reaction.
Therefore, option A. noble gases have eight electrons in their outermost shell.
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Create a 10 question test to acess the improrant topics on deposition, weathering and erosion. you may use multi choice, open ended questions, and fill in the blanks. Put the answers in the question as a resourse to help you.
Answer:
What is deposition?How does acid rain erode rocks?Fill in the blanks: The very strong _______ would burn if they contacted the skin and can also destroy ______, but _______ rain is much weaker and could never burn the skin.What is the cause of acid rain?Acid rain is rain that is usually _______What is the most important source of acid rain?What can rocks exposed to acid rain do?Explain the difference between weathering and erosion?What can deposition create?State some types of erosion?Explanation:
Deposition was the opposite of sublimation.It infiltrates the cracks below the groundThe very strong acids would burn if they contacted the skin and can also destroy metals, but acid rain is much weaker and could never burn the skin.Acid rain is caused by a chemical reaction that begins when compounds like sulfur dioxide and nitrogen oxides are released into the air.acidicvolcanoesPoison ecosystemsWhen the smaller rock pieces (now pebbles, sand or soil) are moved by these natural forces, it is called erosion. So, if a rock is changed or broken but stays where it is, it is called weathering. Deposition creates many types of landforms on earth. Gravity and weight create rockslides on the sides of hills and mountains, depositing rocks at the bottom.It consists of different types like water, wind, ice, thermal and gravity erosionStars in the sky appear to be moving. What do we call this conclusion that is based on observations, clues, or evidence?(2 points)
A.Hypothesis
B.Inference
C.Procedure
D.Report
Answer:
B. Inference
Explanation:
I dont have one but when i took a quiz it said it was right
Stars in the sky appear to be moving. We call this conclusion that is based on observations, clues, or evidence is Inference.
What is inference?An inference is a conclusion that we can make when we have seen evidences of some particular situations and according to that we give statements.
For example-
1. If someone made a bad face just after taking a bite of food then we can infer that the person didn't like the food.
2. If someone is going away from a place after another person arrived then we can infer that the first person doesn't like the second person.
3. If someone is very lazy from the beginning of the day then we can infer that the person didn't take proper rest.
Given options are-
A. Hypothesis
B. Inference
C. Procedure
D. Report
Therefore, Stars in the sky appear to be moving. We call this conclusion that is based on observations, clues, or evidence is Inference.
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Soda pop is carbonated with CO2. Mark puts one bottle of soda pop in the refrigerator and leaves the other out in the hot sunlight. After one hour, he opens both bottles. Which bottle will likely have more fizzing and bubbles? Why?