The heat required : 840 J
Further explanationGiven
mass of water = 20 g
Temperature : 30°C to 40°C
Required
Heat to raise the temperature
Solution
Heat can be calculated using the formula:
Q = mc∆T
Q = heat, J
m = mass, g
c = specific heat, joules / g ° C (for water= 4.18 J/g° C)
∆T = temperature difference, ° C / K
The heat :
[tex]\tt Q=20\times 4.2\times (40-30)\\\\Q=\boxed{\bold{840~J}}[/tex]
Question 11 of 32
When do scientists form a hypothesis?
A. Before they form a theory
B. After they form a theory
O C. Before they perform an experiment
D. After they perform an experiment
SUBMIT
Answer:
C
Explanation:
a hypothesis always comes first
Answer:
C
Explanation:
They form hypothesis first, then perform the experiment to test the hypothesis. After multiple experiments, they form a theory.
Thus C is correct
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What did the Curies conclude about radioactivity based on their studies?
A. The amount of radioactivity is an extensive property because it varies as the amount of material varies.
B. The amount of radioactivity is an extensive property because it remains constant as the amount of material varies.
C. The amount of radioactivity is an intensive property because it varies as the amount of material varies.
D. The amount of radioactivity is an intensive property because it remains constant as the amount of material varies.
Answer:
c
Explanation:
Both the esophagus and the small intestine are involved in the digestion of food. The esophagus squeezes food into the stomach by wave-like muscle contractions. Peptidase enzymes in the small intestine break food molecules into smaller molecules.
Which statement best describes changes to food during digestion?
A. The muscle contractions result in physical changes, while the action of the peptidase results in chemical changes.
B. The muscle contractions result in chemical changes, while the peptidase results in physical changes.
C. The muscle contractions and the action of the peptidase both result only in physical changes.
D. The muscle contractions and the action in the peptidase both result only in chemical changes.
Answer:
The answer is: A
Explanation:
The wave-like contractions are to be considered a physical change as they do not take part in the breaking-down of the food. The peptidase is a chemical change because it is used to chemically break down the food to retrieve nutrients and such.
Dan wants to test the effects of different amounts of antibiotic on bacteria. While setting up his experiment he makes sure to use the same type of antibiotic, the same type of bacteria, and the same type of incubator for each trial. Which phrase below best describes this part of the experiment?
Answer:
C
Explanation:
A. analyzing results
B. collecting data
C. choosing controlled variables
D. making a prediction
The correct answer would be choosing controlled variables.
The controlled variables are factors that are kept constant among the different groups of subjects during the course of an experiment so as to be able to isolate the effects of a single factor - the independent variable.
There are basically 3 types of variables in a scientific experiment;
1. The independent variable
2. The dependent variable
3. The controlled variable
The independent variables are the variables whose effects are to be determined in the course of experiments. The dependent variables are the variables that are actually measured during the course of experiments and whose values vary along with that of the independent variables. The controlled variables are other variables required for the experiment but which must be kept constant among subjects in order to be able to isolate the effects of the independent variable.
The correct option is C.
1. Does elevation play a factor? If so, can the elevation be changed to protect the homes? 2. Could the residents build a structure that would prevent a tsunami from reaching the community? What would this structure look like? How would the residents build it? 3. What could limit the erosion of the beach?
Answer:
Yes.
Explanation:
Yes, elevation play a great role and has the ability to protect homes from natural disasters such as flood and tsunami etc. The residents build a hard structure of wall along the beach that would prevent a tsunami from reaching the community and also built homes at higher elevation. The residence built it with the help of government and this wall is also effective in reducing the erosion of the beach.
Answer:
1. Yes elevation does play a factor if the house was higher i feel like it wouldnt get as damaged
2. Yes they could build a high enough wall that it would take most of the impact away from the houses, you would build it with the thickest peice of wood that you could find and use long screws and cement the wood into the ground.
3. The wall will also help from erosion
Explanation: i got it right on my project.
For questions 14-16 pick out the variables that will be needed to answer the following question: Do trees grow faster if it is wetter in the summer?
14) What is the independent variable?
a.) amount of rain
b.) no rainfall
c.) amount of growth
15) What is the dependent variable?
a.) amount of rain
b.) no rainfall
c.) amount of growth
16) What is the control?
a.) amount of rain
b.) no rainfall
c.) amount of growth
Answer:
14) A. amount of rain
15) C. amount of growth
16) B. no rainfall
Explanation:
6e7eyehdjjdueebbevdvdvebe
Help with this question
Answer:
So the number of protons equals the number of electrons.
Explanation:
Ionic bond, also called an electrovalent bond, type of linkage formed from the electrostatic attraction between oppositely charged ions in a chemical compound. Such a bond forms when the valence (outermost) electrons of one atom are transferred permanently to another atom.
A 0.85% saline solution is: a.8.5 mL of saline added to 91.5 mL of water b.85 g of NaCl made up to 1,000 mL of water c.0.85 g NaCl made up to 100 mL of water d.8.5 g NaCl in 100 mL of water
Answer:
c
Explanation:
A 0.85% saline solution would consist of 0.85 g NaCl made up to 100 mL of water.
A 0.85% saline solution contains 0.85% by weight of NaCl. Hence, in order to prepare such a solution, 0.85 g of NaCl is weighed out into a beaker or cylinder and distilled water is added up to the 100 mL mark. On the other hand, 8.5 g of the NaCl can be weighed out and then distilled water added to 1000 mL mark.
The correct option is, therefore, c.
The curved upper surface of a liquid in a column of liquid?
Answer:
The answer would be meniscus.
What object do you think will take up
more space? Why do you think this?
Answer:
solids
Explanation:
BC they r heavier than liquid and gas
X-rays had a frequency of about 3x10^18 determine it's wavelength (in nm) and energy per photon
Answer:
λ = 0.1 nm
E = 2 × 10⁻¹⁵ J
Explanation:
Step 1: Given data
Frequency of X-rays (ν): 3 × 10¹⁸ s⁻¹
Step 2: Calculate the wavelength (λ) of a photon of X-rays
We will use the following expression.
c = λ × ν
where,
c: speed of light
λ = c / ν
λ = (3.00 × 10⁸ m/s) / 3 × 10¹⁸ s⁻¹
λ = 1 × 10⁻¹⁰ m × (10⁹ nm/1 m) = 0.1 nm
Step 3: Calculate the energy (E) of a photon of X-rays
We will use the following expression.
E = h × ν
where,
h: Planck's constant
E = 6.63 × 10⁻³⁴ J.s × 3 × 10¹⁸ s⁻¹
E = 2 × 10⁻¹⁵ J
What are the needs & advantages of career planning?
in the blanks using the options given below:
Career is a sequence of related jobs arranged in a .........order.
Wrong choice of career may lead to.................
Agriculture, veterinary and nursing provide better........ ... to
young people.
Poor health and safety condition in an organization
causes.................effect on the choice of career.
The essence of career planning is the................ of individual goal
with organizational goal.
gative, hirarchical, frustration, bridging, lucrative, attraction
Answer:
The correct options are;
1) Hierarchical
2) Frustration
3) Attraction
4) Gative
5) Bridging
Explanation:
A career can be defined as a person's trade or occupation, which he or she engages and progresses in for a considerable portion of his or her life
When a person is engaged in a career that is not best suited to them can therefore lead to frustration, due to the length of time required in building a career
Agriculture, veterinary and nursing are mainly hands on or time input (for agriculture) careers, that seek to attract young people
The existence of poor health and safety conditions in an organization limits the advancement of individuals in their chosen career within the organization
Therefore, we have;
Career is a sequence of related jobs arranged in a hierarchical order
Wrong choice of career may lead to frustration
Agriculture, veterinary, and nursing provide better attraction to young people
Poor health and safety conditions in an organization causes gative effect on the choice of career
The essence of career planning is the bridging of individual with organizational goal.
What is the bond angle that corresponds to the
geometry associated with C1 in the structure?
A. 120° B. 90O
C. 1800
D. 109.5o
7. Between which bonded elements in the above
structure is there the strongest dipole moment?
A. Carbon to Carbon B. Hydrogen to Carbon
C. Oxygen to Carbon D. Oxygen to Hydrogen
8. What is the geometry associated with the C2 molecule in the structure?
A. linear B. trigonal planar C.bent D. tetrahedral
9. Among the choices below, which correctly describes the bonding taking place in the above structure?
A. 6 sigma bonds, 1 pi bond C. 6 sigma bonds, 2 pi bonds
B. 7 sigma bonds, 1 pi bond D. 7 sigma bonds, 2 pi bonds
3 The weight of an atom is determined primarily by —
A) the total number of protons plus neutrons
B) the total number of protons plus electrons
C) the total number of neutrons plus electrons
D) the total number of electrons, protons, and neutrons
Answer:
A)The total number of protons plus neutrons= Weight of an atom
What is the approximate energy of a photon having a frequency of 4 x 10^7 Hz? (h = 6.6 x 10^-34 J . s)
Answer:
2.64 ×[tex]10^{-26}[/tex] J
Explanation:
I think you should mark it a physics question instead but anyway.
---------------------------------------------------------------------------
The Planck equation should be applied:
E = hv , while E is energy of proton; h is Planck constant; and v is frequency.
E = 6.6 × [tex]10^{-34}[/tex] × 4 × [tex]10^{7}[/tex]
= 6.6 × 4 × [tex]10^{-27}[/tex]
= 2.64 ×[tex]10^{-26}[/tex] J
If 56 grams of nitrogen is mixed with 56 grams of oxygen, what is the pressure of each gas if the total
pressure is 1320 Torrs?
Answer:
pN₂ = 695 torr; pO₂ = 625 torr
Explanation:
Step 1: Calculate the moles of each gas
The molar mass of N₂ is 28.01 g/mol.
56 g × 1 mol/28.01 g = 2.0 mol
The molar mass of O₂ is 32.00 g/mol.
56 g × 1 mol/32.00 g = 1.8 mol
Step 2: Calculate the total number of moles
n = nO₂ + nN₂ = 1.8 mol + 2.0 mol = 3.8 mol
Step 3: Calculate the partial pressure of each gas
We will use the following expressions.
pN₂ = P × X(N₂)
pN₂ = 1320 torr × (2.0 mol/3.8 mol)
pN₂ = 695 torr
pO₂ = P × X(O₂)
pO₂ = 1320 torr × (1.8 mol/3.8 mol)
pO₂ = 625 torr
How does the atomic radius of an element is related to its metallic character
Answer:
The large the atomic radius the more the metallic character of elements
Explanation:
The atomic radius is related to the metallic character in a way that the larger the atomic radius, the more metallic a body becomes.
Therefore, as we go down a group, metallic character increases.
Metallic character relies on the ability and willingness of an atom to share its valence electrons. As the size of an atom becomes large, the more metallic it is and the more its metallic character. In some other cases this character is known as electropositivity.Write True/False against the following statements and also correct the false statement.
Greater the calorific value better is the fuel.
Answer:
I think it is true you should go for true
Write the name of the covalent compound ON.
Answer:
the answer is oxygen mononitride
Which of the following is NOT needed for photosynthesis to take place?
A. glucose
B. chlorophyll
C. water
D. light energy
Diffraction is a wave property that electrons possess
- true
- false
Answer:
The given statement is "True". A further explanation is provided below.
Explanation:
Diffraction occurs mostly with general noise, with electro-magnetic radioactive material, such as visible region, x-ray, but mostly gamma rays, and with very small moving molecules, such as atomic nuclei, as well as electrons, that also have wavelike characteristics. Yet another side effect of diffraction is because there are no dramatic or rapid shadows.Therefore this obvious response is the right one.
please help im stuckkkk
Answer:
Just in case you want confirmation yes, its mid ocean ridge
Hi! Can you help me with this?
Is a hydrogen gas a element, compound, or mixture?
Answer:
Hydrogen gas (H2) is a molecule, but not a compound because it is made of only one element. Water (H2O) can be called a molecule or a compound because it is made of hydrogen (H) and oxygen (O) atoms.
Explanation:
Hope this helped!!!
-BB
please mark me brainly
Answer:
It's an element. :)
Explanation:
Because of this, railroads use the reaction to provide molten steel to weld steel rails together when laying track. When 23.00g of iron(III) oxide reacts with aluminum metal, how many moles of molten iron (Fe) are formed
Answer:
0.288 mole of Fe.
Explanation:
We'll begin by calculating the number of mole present in 23.00g of iron(III) oxide (Fe2O3). This can be obtained as follow:
Mass of Fe2O3 = 23 g
Molar mass of Fe2O3 = (56×2) + (16×3)
= 112 + 48
= 160 g/mol
Mole of Fe2O3 =?
Mole = mass /Molar mass
Mole of Fe2O3 = 23 / 160
Mole of Fe2O3 = 0.144 mole
Next, we shall write the balanced equation for the reaction. This is given below:
2Al + Fe2O3 —> Al2O3 + 2Fe
From the balanced equation above,
1 mole of Fe2O3 reacted to produce 2 moles of Fe.
Finally, we shall determine the number of mole of Fe produced by the reaction of 23 g (i.e 0.144 mole) of Fe2O3. This can be obtained as illustrated below:
From the balanced equation above,
1 mole of Fe2O3 reacted to produce 2 moles of Fe.
Therefore, 0.144 mole of Fe2O3 will react to produce = 0.144 × 2 = 0.288 mole of Fe.
Thus, 0.288 mole of Fe is obtained from the reaction.
what does ǵene of interest¨ mean ?
Help me plz I don’t know what it’s mean
Answer:
1 has the highest density because it has the most amount of circles in the least amount of space- it is the most densely filled with circles; it is the most dense.
Answer:
image 1 would have the highest density
Explanation:
the closer the molecules are the more solid an object is. if the molecules are far apart and rarely bump into eachother, it is more gaseous. the object in the middle (2) is a liquid
There is a photon with an energy of 4.51 x 10^-34 J. What is the wavelength of
this light? in nm
Answer:
4.4045358859215327e-17 nm
Explanation:
Hope this helped!
Which statement best describes what would happen to an ecosystem once the sun is removed?
A. The functions within the ecosystem will eventually stop & everything will die off.
B. The ecosystem will continue to thrive; it does not need the sun's energy to work.
C. The ecosystem will look for a different source of energy to use.
D. The ecosystem will instantly stop working.
Answer:
A. The functions within the ecosystem will eventually stop & everything will die off.
Explanation:
Everything is dependent on the sun --starting from the bottom of the food chain, the producers. However, we wouldn't die instantly because "Earth retains heat fairly well, so humans wouldn't freeze instantly."
The mass of radium-226 in a sample is found to have decreased from 45.00g to 5.625g in a period of 4800 years.From this information. Calculate the half life of radium-226
Answer:
Half life = 1600 years
Explanation:
Given data:
Total mass of sample = 45.00 g
Mass remain = 5.625 g
Time period = 4800 years
Half life of radium-226 = ?
Solution:
First of all we will calculate the number of half lives passes,
At time zero 45.00 g
At first half life = 45.00 g/ 2= 22.5 g
At 2nd half life = 22.5 g/ 2 = 11.25 g
At 3rd half life = 11.25 g/ 2= 5.625 g
Half life:
Half life = Time elapsed / number of half lives
Half life = 4800 years / 3
Half life = 1600 years
Question 10 of 32
Which of the following is an example of how the same chemicals used to
help people can harm the environment?
O A. Phosphates are removed from detergents so they don't end up in
drinking water.
B. Hillsides erode after plants are removed to clear a space for crops.
C. Plants grow back after toxic chemicals are removed from the
surrounding soil.
D. Excess fertilizers run off into rivers and create a dead zone.
SUBMIT
Answer:
D
Explanation:
The correct answer that gives a good example of how the same chemical used to help people can harm the environment would be when excess fertilizers run off into rivers and create a dead zone.
Fertilizers are usually applied to crops as an agricultural practice by farmers to enhance the yield of the crops and boost food or raw materials production. However, excess fertilizer gets washed into nearby water bodies and ends up creating a low-oxygen zone that is incapable of supporting lives within the water body - also known as dead zones.
The correct option is, therefore, D.