Answer:
2.0 × 10⁻³ g
Explanation:
Step 1: Given data
Mass of solution: 1000. g (1.000 kg)Concentration of Br₂: 2.0 ppmStep 2: Calculate the mass of Br₂ required to prepare the solution
The concentration of Br₂ is 2.0 ppm, that is, there are 2.0 mg of Br₂ per kilogram of solution. The mass of Br₂ required to prepare 1.000 kg of solution is:
1.000 kg Solution × 2.0 mg Br₂/1 kg Solution = 2.0 mg
Step 3: Convert the mass to grams
We will use the conversion factor 1 g = 1000 mg.
2.0 mg × 1 g/1000 mg = 2.0 × 10⁻³ g
Which of the following has had the most negative effect on Earth's ecosystems?
A. establishment of air pollution standards.
B. increase in human population
C. recycling glass, plastic, and metals
D. use of natural predators to control pest insects.
Answer:
B
Explanation:
humans are evil, done a lot of negative effects on ecosystem.
Which of the following correctly shows a synthesis reaction involving potassium?
A. Br2 + 2KI → I2 + 2KBr
B. 4K + O2 → 2K2O
C. 2KClO3 → 2KCl + 3O22KClO3 → 2KCl + 3O2
D. 2K2O → 4K + O22K2O → 4K + O2
Answer:
B. 4 K + O₂ → 2 K₂O
Explanation:
Which of the following correctly shows a synthesis reaction involving potassium?
A. Br₂ + 2 KI → I₂ + 2 KBr
No, this is a single displacement reaction, in which Br displaces I from its salt.
B. 4 K + O₂ → 2 K₂O
Yes, this is a synthesis reaction, in which 2 elements combine to form a compound.
C. 2 KClO₃ → 2 KCl + 3 O₂
No, this is a decomposition reaction, in which a big substance decomposes into smaller ones.
D. 2 K₂O → 4K + O₂
No, this is a decomposition reaction, in which a big substance decomposes into smaller ones.
For each of the environments below: (1) identify your system and surroundings and (2) predict whether it would be endothermic or exothermic.a.Wood burningSystem:Surroundings:Enthalpy Change:b.Water freezingSystem:Surroundings:Enthalpy Change:c.Sweat evaporatingSystem:Surroundings:Enthalpy Change:d.Chemical hand-warmerSystem:Surroundings:Enthalpy Change:
Answer:
A) Wood burning
system : Wood.
surroundings : atmosphere
Enthalpy : Exothermic
B) Water Freezing system
System : Refrigerator
surroundings : water in the refrigerator
enthalpy change : Endothermic
C) Sweat evaporating
System : Human being
surroundings : Air nearby
Enthalpy change : exothermic
D) Chemical Hand-warmer
system : Hand warmer pack
Surroundings : human palms
Enthalpy Change : Exothermic
Explanation:
A) Wood burning
system : Wood
surroundings : atmosphere
Enthalpy : Exothermic
This system give away energy to its surroundings hence its enthalpy change is exothermic
B) Water Freezing system
System : Refrigerator
surroundings : water in the refrigerator
enthalpy change : Endothermic
The system absorbs heat from what is put inside(surroundings ) of it hence this is na endothermic system
C) Sweat evaporating
System : Human being
surroundings : Air nearby
Enthalpy change : exothermic
This is an exothermic reaction ( enthalpy change ) because the system gives out heat to the surrounding
D) Chemical Hand-warmer
system : Hand warmer pack
Surroundings : human palms
Enthalpy Change : Exothermic
There is movement of heat from the system to the surrounding hence it is an exothermic reaction
Basic Stoichiometry
Part 1: Mole ←→ Mass Conversions
Choose 2: Convert the following number of moles of chemical into its mass in grams.
1. 0.436 moles of (NH4)Cl = ______g
2. 0.50 moles of Ca(NO3)2 = ______g
Choose 2: Convert the following masses into their corresponding number of moles.
3. 23.5 g of NaCl = ______moles
4. 79.9 g of KMnO4 =______moles
5) The combustion of a sample of butane, C4H10 (lighter fluid), produced 2.46 grams of water.
Answer:
1. 23.3 g
2. 82 g
3. 0.402 mol
4. 0.506 mol
Explanation:
We can convert moles (n) to mass (m) using the following expressions that include the molar mass (M).
n = m/M
m = n × M
1. The molar mass of NH₄Cl is 53.49 g/mol.
m = 0.436 mol × 53.49 g/mol = 23.3 g
2. The molar mass of Ca(NO₃)₂ is 164.09 g/mol.
m = 0.50 mol × 164.09 g/mol = 82 g
3. The molar mass of NaCl is 58.44 g/mol.
n = 23.5 g/(58.44 g/mol) = 0.402 mol
4. The molar mass of KMnO₄ is 158.03 g/mol.
n = 79.9 g/(158.03 g/mol) = 0.506 mol
what statement is the best description of a chemical bond
Answer:
A chemical bond holds atoms together.
Plz help me I am timed!!
Answer:
What do you need help with
Explanation:
Explanation:
okay I'll help but whats the question
Please help with yes or no
At which point on the roller coaster will the car have the greatest amount of Kinetic energy?
Tam a highly reactive alkali metal in period 3 with only one valence electron
O Sodium (Na)
Beryllium (Be)
Magnesium (Mg)
Answer:
Sodium (Na)
Helium
Magnesium (Mg).
Explanation:
From the periodic table, we will understand that the group 1 metals are the alkali metal. However, the period runs from left to right on the periodic table while the group runs from up to down in the periodic table. In period 3, the alkali metal present there with one valence electron in its outermost shell is sodium (Na).
The only noble gas exists in the last group, group zero of the periodic table. However, the only noble gas with two electrons in its outermost shell is called Helium
The ALkaline earth metals are group 2 metals. They are usually shiny metals and the ability to lose 2 electrons in their outermost electron shell. The alkaline earth metal located in period 3 is Magnesium (Mg).
how is acid different from base
What are the two types of bonding we have studied?
a. Metallic and covalent
b. Covalent and ionic
c. lonic and metallic
d. Molecular and metallic
Which expression represents the concentration of OH– in solution?
a. 10–14 / [H3O+]
b. [OH–] / 10–14
c. 10–14 – [H3O+]
d. 10–14 x [H3O+]
The acceleration of a baseball after it is hit by a bat depends on the mass of the ball and the net force on the ball. This example best illustrates which law?
a
Newton's law of universal gravitation.
b
Newton's first law of motion.
c
Newton's third law of motion.
d
Newton's second law of motion.
plz, help me it's urgent
Answer:
Explanation:
A is solid, b is melting, c is freezing, d is liquid, e is evaporating, g is gas, and f is condensation.
Hello Mikaela!
Let's start from the top, letter G. Letter G should be gas. Letter F should be condensation. Letter E should be evaporation. Letter D should be liquid. Letter C should be freezing. Letter B should be melting. And letter A should be solid.
I really hope this helps!!
Determine how many molecules are in 86L of carbon dioxide at STP?
Answer:How can you tell how much gas is in these containers?
Small gas tanks are often used to supply gases for chemistry reactions. A gas gauge will give some information about how much is in the tank, but quantitative estimates are needed so the reaction will be able to proceed to completion. Knowing how to calculate needed parameters for gases is very helpful to avoid running out too early.
Conversions Between Moles and Gas Volume
Molar volume at STP can be used to convert from moles to gas volume and from gas volume to moles. The equality of 1 mole = 22.4 L is the basis for the conversion factor.
Sample Problem One: Converting Gas Volume to Moles
Many metals react with acids to produce hydrogen gas. A certain reaction produces 86.5 L of hydrogen gas at STP. How many moles of hydrogen were produced?
Step 1: List the known quantities and plan the problem.
Known
86.5 L H2
1 mol = 22.4 L
Unknown
moles of H2
Apply a conversion factor to convert from liters to moles.
Step 2: Calculate.
Explanation:
Select the correct answer.
For Al, its atomic number is 13 and its mass number is 27. How many neutrons does it have?
Ο Α. .
13
ОВ.
14
26
OD
27
O E
40
Answer:
B.) 14
Explanation:
27-13=14 neutrons
In the process of photosynthesis, plants take in carbon dioxide (CO2) from the atmosphere and water (H2O) from the soil. Using the energy of sunlight, plants build molecules of glucose (C6H12O6) and oxygen (O2).
Select one:
a.
Plants absorb Carbon Dioxide which increases the amount of carbon in the atmosphere.
b.
Plants produce Carbon Dioxide which increases the amount of carbon in the atmosphere.
c.
Plants absorb Carbon Dioxide which reduces the amount of carbon in the atmosphere.
d.
Plants produce Carbon Dioxide which reduces the amount of carbon in the atmosphere.
Answer:
C
Explanation:
thts the right answwer im sure
Answer:
C
Explanation:
They take in carbon dioxide and make an oxygen. That's why they are encouraging people to plant. Less CO2 more oxygen
Cars are the leading cause of____
1. carbon dioxide
2. nitrogen oxide
3.carbon monoxide
pollution
Answer:
nitrogen oxide
Explanation:
When you work out your cells need
Answer:
Waterrrr
Explanation:
H2O
Answer:
Muscle contraction
Explanation:
According to the new study, exercise improves muscle health by renewing its cellular powerhouse: the mitochondria. Mitochondria are crucial to the good functioning of our bodies, as well as to our overall health and longevity. These tiny parts of the cell turn the food we eat into energy.
Ethanol is a common laboratory solvent and has a density of 0.789 g/mL. What is the mass, in grams, of 133 mL of ethanol?
[tex]V = \text{133 mL}[/tex]
[tex]\rho = \text{0.789 g/mL}[/tex]
Required:[tex]m[/tex]
Solution:[tex]\rho = \frac{m}{V}[/tex]
[tex]m = \rho V[/tex]
[tex]m = (\text{0.789 g/mL})(\text{133 mL})[/tex]
[tex]\boxed{m = \text{105 g}}[/tex]
Ethanol is a common laboratory solvent and has a density of 0.789 g/mL. 105g is the mass, in grams, of 133 mL of ethanol.
What is mass?In physics, mass is a quantitative measurement of inertia, a basic characteristic of all matter. It essentially refers to a body of matter's resistance to changing its speed or location in response to the force that is applied. The change caused by a force applied is smaller the more mass a body has.
The kilogram, which would be specified as equivalent to 6.62× 10³⁴ joule second in terms of Planck's constant, is the unit of mass inside the International Units System (SI).
density = mass / volume
mass =density× volume
= 0.78× 1.33
=105g
Therefore, 105g is the mass.
To know more about mass, here:
https://brainly.com/question/28704035
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The tablets were crushed, and 4.9993 g of the powder was transferred to a beaker and reacted with HCl. After filtration, the filtrate was transferred to a 100-mL volumetric flask and diluted with water. 20.00 mL of this stock solution were combined with 0.2 M Na3PO4. The resulting precipitate weighed 0.3451 g after drying. Calculate the moles of BiPO4 precipitated, the moles of Bi3 in the stock solution, and the mass of BSS per tablet.
Answer:
Explanation:
From the information given:
Mass of BiPO₄ = 0.3451 g
Number of moles of BiPO₄ = [tex]0.3451 \ g \ BiPO_4 \times \dfrac{1 \ mol \ BiPO_4}{303.95 \ g \ BiPO_4}[/tex]
[tex]= 0.001135 \ mol[/tex]
The number of moles of Bi³⁺ in 20.00 mL is:[tex]= 0.001135 \ mol \ BiPO_4 \times \dfrac{1 \ mol \ of \ Bi^{3+}}{1 \ mol \ BiPO_4}[/tex]
= 0.001135 mol of Bi³⁺
The number of moles of Bi³⁺ in 100 mL stock solution
[tex]= 0.001135 \ mol \ Bi^{3+} \times \dfrac{100 \ mL}{20.0 \ mL}[/tex]
[tex]= 0.005675 \ mol[/tex]
Mass of BSS in 4.9993 g tablets
[tex]m = 0.005675 \ mol \ Bi^{3+} \times \dfrac{1 \ mol \ BSS}{1 \ mol \Bi^{3+}} \times \dfrac{362.1 \ g \ BSS}{1 \ mol \ BSS}[/tex]
m = 2.055 g BSS
Mass of BSS in 5.0103 g (5 tables)
[tex]m = 2.055 g \ BSS \times \dfrac{5.0103 \ g}{4.9993 \ g}[/tex]
= 2.06 g
∴
The mass of BSS per tablet is [tex]=\dfrac{2.06 \ g}{5 \ tablet}[/tex]
= 0.412 g BSS/ tablet
what is the most important part of solution preparation
Answer:
id k exactly what your asking
Explanation:
A percent composition analysis yields
22.6% phosphorus (P) and 77.4%
chlorine (CI). What is the empirical
formula for the compound?
А
B
P2C17
PCI:
Answer:
PCl₃
Explanation:
To determine the empirical formula of a compound, we need to follow a series of steps.
Step 1: Divide each percent composition by the atomic mass of the element
P: 22.6/30.97 = 0.729
Cl: 77.4/35.45 = 2.18
Step 2: Divide all the numbers by the smallest one, i.e. 0.729
P: 0.729/0.729 = 1
Cl: 2.18/0.729 ≈ 3
The empirical formula of the compound is PCl₃.
LEVEL 3
Write the correct order
of letters to the finish line.
A E B E C
Example:
ABCGH
G
H
N
eza
Not correct
7th grade science lol help
Answer:
The process you are referrring to is erosion.
Explanation:
Weathering would be the breaking down of rock/other land debris. Its more active counterpart would be erosion, wherein the process transports the bits of rock and minerals away. Hope it helps!
cosity a letter to our mother
who is in lagos Nigeria telling
her about the
the problem you are
facing
in the school and at
home and suggest solution to
you pproblem
Which of the following are diatomic elements? Select all that apply.
A.Hydrogen
B.Boron
C.Bromine
D.Iodine
Answer:
C
Explanation:
A diatomic element in that list is Bromine
How do you decrease the amount of energy storage molecules there are in an ecosystem?
a) increase sunlight
b) decrease sunlight
c) burn dead matter
d) bury dead matter
e) trap carbon dioxide
Decreasing sunlight will decrease the amount of energy storage molecules in an ecosystem.
What is Photosynthesis?This is the process in which green plants manufacture food in the presence of sunlight. Primary producers are involved in this process of providing energy to the ecosystem.
This therefore means that a decrease in sunlight means a decrease in photosynthesis and energy production.
Read more about Photosynthesis here https://brainly.com/question/19160081
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Methane and sulfur react to produce carbon disulfide (CS₂), a liquid often used in the production of cellophane.
2CH₄ + S₈ --> 2CS₂ + 4H₂S
Calculate the moles of H₂S produced when 2.25 mol S₈ is used.
Answer:
9 moles
Explanation:
The balanced chemical equation provided in this question is as follows:
2CH₄ + S₈ → 2CS₂ + 4H₂S
In accordance to the above balanced equation, 1 mole of sulphur (S8) produces 4 moles of hydrogen sulfide (H2S).
Therefore, if 2.25mol of S8 is used, 2.25 × 4 = 9 mol
9 moles of H2S is produced.
Please help me l don’t understand please !!!!!!
Answer: C
Explanation:
he never had evidence in the first place that was nearly enough.
