HELP PLEASE I BEG YOU
Which element is located in period 4?
Silicon (SI)
Iron (Fe)
Beryllium (Be) Zirconium (Zr)
Answer:
i beleive iron
Explanation:
2) You start with 3.8 x 1021 gold atoms, how many moles is this?
Answer:
0.0063mol
Explanation:
Number of moles (n) in a substance can be calculated by dividing the number of atoms (nA) of that substance by Avagadro's number i.e. 6.02 × 10^23. That is; n = nA ÷ 6.02 × 10^23
1 mol of Gold = 6.02 × 10^23 atoms
Therefore, 3.8 x 10^21 atoms of Gold will be;
3.8 x 10^21 ÷ 6.02 × 10^23
= 3.8 ÷ 6.02 × 10^ (21 - 23)
= 0.6312 × 10^-2
= 0.0063mol of Gold
The primary role of ATP is to _______ by transferring a phosphate group to a molecule and forming ADP.
A
provide energy for cellular work
B)
produce heat energy
C)
reduce the activation energy of a reaction
D)
take energy from cellular work
Answer:
A) provide energy for cellular work
Explanation:
The Adenosine triphosphate (ATP) molecule is the nucleotide known in biochemistry as the "molecular currency" of intracellular energy transfer; that is, ATP is able to store and transport chemical energy within cells. ATP also plays an important role in the synthesis of nucleic acids.
ATP always GIVES ENERGY
Which of the following masses is the greatest?
Answer:
4.2 gigagrams
Explanation:
kilo = 1,000
giga = 1,000,000,000
milli = .001
Hockey is a sport in which players use hockey sticks to push a puck across smooth ice. At practice one day, three different-colored hockey pucks were sliding on the ice. The green hockey puck has less mass than the black and purple hockey pucks, which have the same mass. A player hit each hockey puck with a stick, but not from the same direction. Use the information in the diagram to answer.
Which puck(s) experienced the strongest force when hit? How do you know?
Answer:
The purple hockey puck; it takes a stronger force to slow down a more massive object than to speed it up.
Explanation:
Hope this helps! :) Plz mark as brainliest if u can!
The formula for photosynthesis is shown.
64,0 + 600, → CH2+ 60,
What are the reactants of photosynthesis? (7.5A)
A.water and carbon dioxide
B.
oxygen and water
C.
glucose and oxygen
D.carbon dioxide and glucose
5. Keratin and collagen are examples of *
li
Answer:
Structural proteins
Explanation:
Glad I could Help Pls Brainliest
Number 2 plssssssssssssssssssssssssssssssss
Answer:
Its located on North America
TRUE OR FALSE?
Solvents are the component in solutions with highest percent composition
Answer:
True
Explanation:
I think this is a helpful for you
What type of reaction occurs when potassium iodide is combined with lead (II) nitrate?
A. single replacement
b. double replacement
c. synthesis
d. combustion
Answer:
double replacement occurs
22
Which of the following statements about acids and alkalis is TRUE?
(1 Point)
ammonium hydroxide is alkaline due to the presence of OH+ ions
hydroxide ions make sodium hydroxide solution alkaline
O hydrochloric acid solution is acidic because it contains hydride ions
Answer:
''hydroxide ions make sodium hydroxide solution alkaline'' is true.
Explanation:
In the first sentence, OH+ ions is incorrect. It has to be OH- ions.
In the last sentence, hydride ions(H-ions) is incorrect. It has to be hydrogen ions(H+ ions).
true or false. a less reactive halogen will displace a more reactive halogen from an aqueous solution of its salt.
Answer:
I think the answer is false
What is the pH of a buffer solution prepared by mixing 20.0 mL of 0.0800 molL−1NaOH with 20.0 mL of 0.130 molL−1 cacodylic acid?
Answer:
pH = 6.20
Explanation:
The pKa of cacodylic acid is 6.
To solve this question we must use Henderson-Hasselbalch equation:
pH = pKa +log [A⁻] / [HA]
Where pKa is the pKa of the weak acid = 6
And [] could be taken as the moles of A⁻ the conjugate base, and HA, the weak acid.
The moles of the NaOH added to the solution of the weak acid are = Moles A⁻
And moles HA = Initial moles HA - Moles NaOH added
Initial moles HA:
0.0200L * (0.130mol / L) = 0.00260 moles
Moles NaOH:
0.0200L * (0.0800mol / L) = 0.00160 moles = [A⁻]
Moles HA =
0.00260 moles - 0.00160 moles = 0.00100 moles = [HA]
pH = 6 +log [0.00160 moles] / [0.00100 moles]
pH = 6.20The pH of the resulting solution is 1.6.
Let cacodylic acid be HA, mixing cacodylic acid and NaOH, the following occurs;
HA(aq) + NaOH(aq) ------> NaA(aq) + H2O(l)
Number of moles of NaOH = 0.0800 molL−1 × 20.0/1000 = 0.0016 moles
Number of moles of HA = 20.0/1000 × 0.130 = 0.0026 moles
We can see that the HA is in excess, Number of moles of excess acid =
0.0026 - 0.0016 = 0.001 moles
Total volume of solution = 20.0 mL + 20.0 mL = 40 mL or 0.004 L
Molarity of excess acid = 0.001 moles/0.004 L = 0.025 M
pH = -log[H^+]
pH = -log[0.025 M]
pH = 1.6
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How many moles of steam are produced when 5.74 moles of octane (C8H18) react?
Chemical equations consist of the chemical formulas of the reactants on the right
and the chemical formulas of the products on the left.
True
False
_Al + _Fe(NO3)2 -->_Fe + __Al(NO3)3
What is the answer?
Answer:
Option A
Explanation:
The atomic number is the number of protons in the nucleus of an atom.
how do I find lattice energy with the overall heat of dissolution of aluminum sulfate?
Al2(SO4)3=> 2Al³(aq)+ + 3SO4²- (aq) + 318kJ
Explanation:
you can use Born-Lande equation,
U=-(A×e^2×Z+ ×Z- ×N)\r ×(1-1/n)
here,U=lattice energy
A=madelung constant
n=Born exponent(depends on repulsion between ion)
e=charge of electron
Z+,Z-=charge of cation and anion
r=distance between cation and its neighbour anion in
space lattice
Calculate the change in heat (Q) that occurs when 38.68grams of steam at 304°C cools to liquid water at 197°C. (cp = 4.184 J/g°C)
Answer:
Change in heat (Q) = -1.7316 x 10⁴
Explanation:
Given:
Mass m = 38.68 g
Change in temperature Δt = (197-304) = -107°C
Specific heat C = 4.184 J/g°C
Find:
Change in heat (Q)
Computation:
Change in heat (Q) = (C)(m)(Δt)
Change in heat (Q) = (4.184)(38.68)(-107)
Change in heat (Q) = -1.7316 x 10⁴
HELPPPP!!!
Which element has the greatest atomic size?
a) Francium
b) Hydrogen
c) Rubidium
d) Sodium
Answer:
A. Francium
Explanation:
I'm not for sure but I believe this is correct. Hope it helps:)
Calculate the volume which 1.00 mole of a gas occupies at STP.
Answer:
22.4 L
Explanation:
A gas at STP will possess the following;
Pressure (P) = 1 atm
Temperature (T) = 273K
General gas constant (R) = 0.0821 Latm/molK
Using the general gas law formula to calculate the volume a gas of 1 mol will contain;
PV = nRT
V = nRT/P
V = 1 × 0.0821 × 273 ÷ 1
V = 22.41/1
V = 22.4 litres
NEED HELP ASAP!!! 20 POINTS!!
Which of the following is an exothermic reaction?
A) N2(g) + 2O2(g) → 2NO2(g) ∆H = +66.4 kJ
B) 2C(s) + H2(g) +227.4 → C2H2(g)
C) 4Al(s) + 3O2(g) → 2Al2O3(s) + 3351 kJ
D) N2(g) + O2(g) → 2NO(g) ∆H = +182.6
Answer:
exo means energy is released when delta h is + it is endo and when energy is on the reactants side that is energy introduced so endo as well so when energy shows up on the product side that is the exo one
so it is C as that E is listed as a product therefore released
Explanation:
Identify the product(s) in the reaction below. 2H20 - 2H2 + O2 O
A. H₂O O
B. H20 and H2 O
C. H20 and 02 O
D. H2 and 02
H2 and 02 are the products of this chemical reaction because of the splitting of water molecule.
What are the products of this reaction?The products of this chemical reaction are H2 and 02 because when the water molecule dissociates or splits hydrogen and oxygen molecules are formed. We know that water is produced from the combination of hydrogen and oxygen.
So we can conclude that H2 and 02 are the products of this chemical reaction because of the splitting of water molecule.
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4. Salt and water are stirred together in a beaker. The solid salt particles seem to disappear
in the water. Which is the best explanation for the product that is formed?
A) A homogenous mixture has been created C) A compound has been created.
B) A heterogenous mixture has been created D) A new element has been
Answer:
I think C. A compound has been created
HELP PLEASE ||Suppose you add water to a 6 g of sugar to make a solution with a concentration of 3 g/L. What is the total volume of the solution?
Answer:
2 L
Explanation:
Divide the mass by the concentration to find the volume.
(6 g)/(3g/L) = 2 L
According to the concept of solubility, in order to make solution of sugar the total volume of solution is 2 g/L.
What is solubility?Solubility is defined as the ability of a substance which is basically solute to form a solution with another substance. There is an extent to which a substance is soluble in a particular solvent. This is generally measured as the concentration of a solute present in a saturated solution.
The solubility mainly depends on the composition of solute and solvent ,its pH and presence of other dissolved substance. It is also dependent on temperature and pressure which is maintained.Concept of solubility is not valid for chemical reactions which are irreversible. The dependency of solubility on various factors is due to interactions between the particles, molecule or ions.
In order to calculate total volume of solution divide mass/ concentration that is 6/3=2 g/L.
Thus, the total volume of the solution is 2 g/L.
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what is change in science
Answer:
Scientific change is: "Any change in the scientific mosaic, i.e. a transition from one accepted theory to another or from one employed method to another. "
Explanation:
What is the name for Fe2(CO3)3?
Answer:
thing
Explanation:
always
4. Calculate the mass of each element:
a) 3.25 mol of He
b) 0.0455 mol of Ni
c) 1.33 mol of K
Name two chemical used to disinfect water
Answer:
chlorine and I think maybe sulphur. but check the internet
Answer:
chlorine I think so . sorry if it ain't the right answer