Answer:
A
A pulley changes the direction of your force, but requires a greater input force.
Explanation:
A pulley changes the direction of your force, but requires a greater input force when machine does work. so option A is correct.
What is machine ?Any tool that makes work easier is a machine. We can complete tasks with the aid of machines by using less force and energy.
By using a simple machine, you can move anything with less effort, but you have to move it farther to do the same amount of labor.
Our bodies function like machinery. For instance, our arms can be compared to a machine that can be utilized to quickly lift objects.
By using a machine to perform work, either the force or the distance across which the force is delivered may rise, but not both at once. In other words, as one grows, either force or distance, the other must decrease. The force-distance trade off is what is meant by this.
Thus, option A is correct.
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5. Where are red blood cells produced?
10 points
a. in the heart
b. in the blood vessels
c. in bone marrow
d. in the plasma
Answer:
C
Explanation:
In the bone marrow, red blood cells are produced
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.
One isotope of a nonmetallic element has mass num- ber 127 and 74 neutrons in the nucleus. The anion derived from the isotope has 54 electrons. Write the symbol for this anion.
Answer:
I⁻
Explanation:
The identity of the element is obtained when the proton number is known.
Mass Number = 127
Neutrons = 74
Number of protons is obtained from;
Protons = Mass Number - Number of Neutrons
Protons = 127 - 74 = 53
The element is Iodine and it's symbol is I.
However, The anion derived from the isotope has 54 electrons
A neutral Iodine should have 53 electrons. This means it has gained a single electron. The symbol is now written as;
I⁻
The SI unit for length is?
Answer:
Metre
Explanation:
the SI unit of length is Metre
Answer:
The SI unit for length is Meter
How many moles are there in 1.68 * 10 ^ 24 molecules of nitrogen dioxide?
Answer:
2.79 molesExplanation:
To find the number of moles in a substance given it's number of entities we use the formula
[tex]n = \frac{N}{L} \\[/tex]
where n is the number of moles
N is the number of entities
L is the Avogadro's constant which is
6.02 × 10²³ entities
From the question we have
[tex]n = \frac{1.68 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 2.790697 ...[/tex]
We have the final answer as
2.79 molesHope this helps you
Explain why PCI5 can be formed whereas
PI5 cannot be formed.
Answer:
highly unstable
Explanation:
also, due to repulsion of lone pairs and instability it breaks and can't form PI5
hope that helps....
what is it called when a substance that is dissolved in liquid
why is newtons first law of motion important to science plsss help :(
Explanation:
every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force
Answer: Newton's 1st law of motion explains how things move and how forces work on their movement, which makes it an extremely important discovery.
Explanation: If we were to place an object into space, we could observe how it behaves without any external influences.
3. What do platelets do?
10 points
O a. help build the number of white blood cells
O b. help build the number of red blood cells
O c. help stop bleeding
O d. gives blood its color
Answer:
C help stop bleeding
Explanation:
Platelets stop bleeding by clumping and forming plugs in blood vessel injuries
Of the elements Pt, V, Li, and Kr, which is a nonmetal?
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
look.............................................
Answer:
Your answer is correct.
Explanation:
The steel paper clip would only move because it has steel in it, which is a magnetized material, plastic on the other side, is made up of polymers which are not attracted to the magnetic force, causing it not to move.
Which value indicate the strongest base
A. pH of 2
B. pH of 5
C. ph of 12
D. pH of 8
Explanation:
The highest number is the strongest base. Therefore the pH of 12 is the strongest base here (C).
Select the item with the highest embodied energy for a typical American. A. Organically grown oranges transported 500 miles by truck B. Pineapple imported by air from Costa Rica C. Sweet corn produced locally using synthetic fertilizer D. Green beans grown in the backyard garden
Answer:
B: Pineapple imported by air from Costa Rica
Explanation:
Embodied energy is the total energy that is required for the extraction, processing, manufacture and transportation of materials to its intended usage destination.
This means highest embodied energy will be the work that demands the most energy for extraction, processing, manufacture and transportation of materials to its intended usage destination.
Looking at the options given, the one with the highest embodied energy will be "Pineapple imported by air from Costa Rica". This is because other options are done locally and thus will consume lesser energy and processing time unlike the pineapple that is coming from another country and by air.
The temperature of a 9.0 g sample of glass changed from 20 to 50 when it absorbed 680 J of heat. What is the specific heat of this glass sample?
Answer:2518.5J/kg/K
Explanation:
A 500 mL sample of drinking water contains 0.001 mg of mercury. How many ppb is this?
Answer:
The value is [tex]k = 2 \ ppb[/tex]
Explanation:
From the question we are told that
The volume of the drinking water is [tex]V = 500 \ mL = 500 *10^{-3} \ L = 500 *10^{-6} \ m^3[/tex]
The mass of mercury it contains [tex]m_c = 0.001 \ mg = 0.001 *10^{-3} \ g = 0.001 *10^{-6}\ kg[/tex]
Generally the mass of water is mathematically represented as
[tex]m = V * \rho[/tex]
Here [tex]\rho[/tex] is the density of water with value [tex]\rho = 1000 \ kg/m^3[/tex]
So
[tex]m = 500 *10^{-6 }* 1000[/tex]
=> [tex]m = 0.5 \ kg[/tex]
Generally ppb mean part per billon , and 1 billon is 100,000,000
So the part per billon which this represents is mathematically represented as
[tex]k = \frac{0.001 *10^{-6}}{ 0.5} * 100 000 000[/tex]
=> [tex]k = 2 \ ppb[/tex]
Answer:
2 ppb
Explanation:
I got it right in class!
Hope this Helps!! :))
Identify the source of energy in a chemical reaction.
(0)A mixture of dihydrogen and dioxygen at one bar pressure contains 70% by weight of dioxygen. Calculate the partial pressure of dioxygen.
a (ii)Calculate the volume occupied by 8.8 g of CO2 at 31.1°C and 1 bar pressure. R = 0.083 bar L K-1 mol-1
Answer:
a) 0.13 bar
b) 5.05 L
Explanation:
Let us take the mass of the mixture to be 100 g. Hence, 70% by weight of dioxygen corresponds to 70 g
Mass of dihydrogen = 100g - 70 g = 30g
Number of moles of dioxygen = 70g/32 g/mol = 2.2 moles of dioxygen
Number of moles of dihydrogen = 30g/2g/mol = 15 moles of dihydrogen
Total number of moles = 2.2 + 15 = 17.2 moles
Mole fraction of dioxygen = 2.2/17.2 = 0.13
Partial pressure = mole fraction * total pressure
Partial pressure of dioxygen = 0.13 * 1 = 0.13 bar
ii) number of moles in 8.8 g of CO2 = 8.8g/44g/mol = 0.2 moles
T = 31.1 + 273 = 304.1 K
P = 1 bar
V= ?
R = 0.083 bar L K-1 mol-1
From
PV=nRT
V = nRT/P
V= 0.2 * 0.083 * 304.1/1
V= 5.05 L
living things
O cell wall
O chloroplasts
O Organelle
O organisms
Which of the following statements about energy is NOT TRUE?
O Energy is the ability to do work or cause change.
Energy can neither be created nor destroyed.
When you use energy, the total amount of energy decreases.
Energy can be changed from one form to another.
Answer:
when you use energy , the total amount of energy decreases.
The temperature of an object is directly related to
A.
the mass of the object.
B.
the motion of its particles.
C.
the potential energy of its chemical bonds.
D.
the volume of the object.
Answer:B
Explanation:Because when the object heats up the particles move faster and it will turn into a liquid or gas but if it is being cooled then the particles will slow down and either make a liquid or solid.
which statements are wrong about atoms
Answer: Atoms are not able to exist independently
Explanation:
Can someone help me on this? (The second one has the same options as the first one)
Answer:
EASY ITS BUILT DIFERENT
Explanation:
Which statement describes a property that is unique to metalloids?
Answer:
Posses both metal and non metal property
This question most likely has answer choices. The answer choices are as follows:
Metalloids are shiny.Metalloids are semiconductive.Metalloids are solid.Metalloids are brittle.The answer is Metalloids are semiconductive (2nd option).
One characteristic that salt water and sugar-water have in common is, at room temperature, they are
a)gases
b)solids
c)mixtures
d)elements
Answer:
The one thing they have in common is that They are mixtures
Answer:
they are both mixtures
Explanation:
2. How many moles are found in 3.2 x 1023 atoms of NaCl?
Answer:
0.53 mol NaCl
General Formulas and Concepts:
Chemistry - Atomic Structure
Using Dimensional AnalysisAvogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.Explanation:
Step 1: Define
3.2 × 10²³ atoms NaCl
Step 2: Identify Conversions
Avogadro's number
Step 3: Convert
[tex]3.2 \cdot 10^{23} \ atoms \ NaCl(\frac{1 \ mol \ NaCl}{6.022 \cdot 10^{23} \ atoms \ NaCl} )[/tex] = 0.531385 mol NaCl
Step 4: Check
We are given 2 sig figs. Follow sig fig rules and round.
0.531385 mol NaCl ≈ 0.53 mol NaCl
What is the volume of 2 moles of He at STP?
Answer:
STP conditions imply a temperature of 273.15 K and a pressure of 100 kPa. When tose conditions are met, 1 mole of any ideal gas will have a volume of 22.7 L. So, if 1 mole occupies a volume of 22.7 L, 2 moles will occupy a volume twice as big. Likewise, 0.5 moles will occupy half the volume 1 mole occupies. Assuming that the gas is at standard temperature and pressure (STP), one mole of any gas occupies 22.4 L . This means the number of moles of O2 is 222.4=0.089 mol .
Explanation:
Select the correct answer from each drop-down menu
The rock cycle
Answer:
The picture?
Explanation:
Please the picture
This makes no sence. Please put the picture up for us to answer. Thanks!
Consider the following balanced equation:
P4(s) + 6F2(e)
4PF3(g)
If 1.25 moles of P4(s) is reacted with 6 moles of F2(g), How many moles of PF3(e) are
produced?
O 5 moles
4 moles
O 6 moles
O 3 moles
Moles of PF₃ : 4
Further explanationA reaction coefficient is a number in the chemical formula of a substance involved in the reaction equation. The reaction coefficient is useful for equalizing reagents and products.
Reaction
[tex]\tt P_4(s)+6F_2(g)\rightarrow 4PF_3(g)[/tex]
1.25 moles of P₄(s) is reacted with 6 moles of F₂(g)
Limiting reactant : the smallest ratio (mol divide by coefficient)
P₄ : F₂ =
[tex]\tt \dfrac{1.25}{1}\div \dfrac{6}{6}=1.25\div 1\rightarrow F_2~limiting~reactant(smallest~ratio)[/tex]
mol PF₃ based on mol of limiting reactant(F₂), so mol PF₃ :
[tex]\tt \dfrac{4}{6}\times 6~moles=4~moles[/tex]
How many moles of sodium cyanide (NaCN) would be needed to
produce 4.2 moles of sodium sulfate (Na2SO4)? (4 points)
H2SO4 + 2NaCN → 2HCN + Na2SO4
O 2.1 mol NaCN
O 4.2 mol NaCN
O 8.4 mol NaCN
O 12.0 mol NaCN
Answer:
c
Explanation:
8.4
For the reaction H₂SO₄ + 2NaC≡N → 2HC≡N + Na₂SO₄, we have that 8.4 moles of sodium cyanide are needed to produce 4.2 moles of sodium sulfate (option C).
The reaction between sodium cyanide and sulfuric acid is:
H₂SO₄ + 2NaC≡N → 2HC≡N + Na₂SO₄
We can find the number of moles of sodium cyanide, assuming that it is the limiting reactant and knowing that 2 moles of it produce 1 mol of sodium sulfate, as follows:
[tex] n_{NaC\equiv N} = \frac{2\: moles\: NaC\equiv N}{1 \: mol\: Na_{2}SO_{4}}*4.2 \: moles\: Na_{2}SO_{4} = 8.4 \: moles [/tex]
Therefore, 8.4 moles of sodium cyanide are needed to produce 4.2 moles of sodium sulfate (option C).
Learn more about limiting reactants here:
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I hope it helps you!